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Re: [hreg] Solar Attic Fans OPPS

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  • Environment Associates Architects
    John: See my comments in green below. Also, what most people may not realize is that I don t sell any construction products, building equipment, solar,
    Message 1 of 17 , Dec 12, 2004
      John:
       
      See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 
       
      LaVerne A. Williams, AIA, LEED AP
      architect & building ecologist
      LaVerne@...
      ENVIRONMENT ASSOCIATES, Architects & Consultants
      5828 Langfield Road
      Houston, TX 77092-1429
      713.528.0000
      866.815.2527 toll free
      www.environmentassoc.com
      30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
      Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
      ----- Original Message -----
      Sent: Sunday, December 12, 2004 5:30 PM
      Subject: Re: [hreg] Solar Attic Fans OPPS

      Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)
       
       It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)
      I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
       
       Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 
      I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
       
       
      Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston, as there were tens of thousands, if not more, installed.)
       
      We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)
       
      regards
       
       
      John Miggins
      Harvest Solar & Wind Power
      "renewable solutions to everyday needs"
      www.harvest-energy.com
      Phone/Fax 918-743-2299
      Cell: 918-521-6223
      ----- Original Message -----
      Sent: Sunday, December 12, 2004 1:06 PM
      Subject: Re: [hreg] Solar Attic Fans OPPS

      Opps.    Please see my correction/comments below in GREEN to my original email.
       
      LaVerne
      ----- Original Message -----
      Sent: Sunday, December 12, 2004 12:29 PM
      Subject: Re: [hreg] Solar Attic Fans

      Mike:
       
      Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
       
      (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
       
      Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
       
      If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
       
      Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
       
      Hope this helps. 
       
      LaVerne A. Williams, AIA, LEED AP
      architect & building ecologist
      LaVerne@...
      ENVIRONMENT ASSOCIATES, Architects & Consultants
      5828 Langfield Road
      Houston, TX 77092-1429
      713.528.0000
      866.815.2527 toll free
      www.environmentassoc.com
      30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
      Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
       
      **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
       
       
       
      ----- Original Message -----
      Sent: Saturday, December 11, 2004 7:20 PM
      Subject: [hreg] Solar Attic Fans

      Hello,

       

      I guess I have to start somewhere..So I will start with attic fans.

       

      I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

       

      Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

       

      Some questions I have are:

       

      1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
      2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
      3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
      4. Anything else I’m missing?

       

      Thanks in advance for your time!!!

       

      Mike Schmitt

       

       

       

       



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    • Paul Archer
      ... FWIW, some of us read our mail in text-only (no HTML) formats, and others may be vision impaired and have text-to-speech or braile readers. The point is
      Message 2 of 17 , Dec 12, 2004
        10:25pm, Environment Associates Architects wrote:

        >
        > See my comments in green below.

        FWIW, some of us read our mail in text-only (no HTML) formats, and others
        may be vision impaired and have text-to-speech or braile readers.
        The point is that putting your comments in color makes them impossible to
        pick out for some people. The most universal way (and the only way
        guaranteed to be understood by any reader (human or machine)) to make
        comments in an email is to put the comments on separate lines below the
        line(s) you are commenting on.

        I'd like to know what your comments are, but I can't pick them out from the
        other text...

        Paul Archer


        >
        > LaVerne A. Williams, AIA, LEED AP
        > architect & building ecologist
        > LaVerne@...
        > ENVIRONMENT ASSOCIATES, Architects & Consultants
        > 5828 Langfield Road
        > Houston, TX 77092-1429
        > 713.528.0000
        > 866.815.2527 toll free
        > www.environmentassoc.com
        > 30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
        > Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
      • John Miggins
        Laverne, I am not an architect and I am sure that with proper design, passive ventillation can work. Your house is a great example of this, your attic is cool
        Message 3 of 17 , Dec 12, 2004
          Laverne, I am not an architect and I am sure that with proper design, passive ventillation can work.  Your house is a great example of this, your attic is cool because it was designed to be so.What I have experienced is that most homes do not have enough or proper attic ventillation. Since they are already built one remedy is to use positive attic ventillation (some sort of fan)
           
           
          My experience is contrary to your original conclusion.  You mentioned a study in the 70's, could not remember who did it but concluded that attic fans have no economic benefit above their cost.  (what kind of attic fans, living space or crawl space) This is general and out of date information in my opinion, solar attic fans were not around in the 70's to be studied.
           
          We have hands on experience with this product in hundreds of houses with different attics, siting, wind , shading etc...and yes marketing fluff that may not always be 100% correct but here is the basics of what I would argue is the benefit of attic ventillation, no matter how it is achieved. Let me know if these conclusions are wrong.
           
          Hot attics are bad(in summer anyway). transfers heat to living space, heats up cold air in air ducts making AC work harder. Also deteriates your roof considerably, most roofs deteriate from heat and heat from the bottom.  I have seen roofs that are only 1 year old and they are brittle due to being too hot in the attic.
           
          Air movement cools attics- bringing in air to change out the attic air cools the attic, may bring in moisture as well, personally the moisture claims of the product are not that much of a concern to me, probably marketing fluff.   Texas does have some mold problems though.
           
          Solar attic fans cost comparable to AC models when you consider installation, wiring etc.. not to mention operating costs.  DC Fans run cooler, last longer and are much quieter than AC fans, also less fire hazard to DC power,  Solar panels have 10 year warranty, most are made by major mfg and have proven to last many years, motor has 5 year warranty.  Much sturdier frame than the $89.00 AC models which only carry a 3 to 5 year warranty.  How long do they last?  I have seen plenty of dead ones.
           
          Look at my first response more closely, I said they cool the attic 20 to 30 degrees which transfers to cooler air coming out of the vents that run through the attic, ie ac vents by 2 to 3 degrees.  This illustrates the thermal effect of hot attics on your AC system.
           
           
          Fairly simple, Hot attics bad,  Ventillation good.
          (Most )Passive ventillation - slow- attics still hot, hot is bad, cost more money to cool.
          Active ventillation - faster- attic much cooler, cooler is good. cost less money to cool house.  Buy more solar!
           
          Solar good for environment, good for attics, good for everyone and yes good for me but this does not diminish the benefits of the product or the service.  Solar Attic fans were rated as one of the 10 best investments under $500 that homeowners can make for energy efficiency.    I have tried them and stand behind them, they work.
           
          Easy way to start on solar power.  Make a statement.
           
          If you want I will install one for you to try for two months this summer and you can measure the difference in attic temperature and electric bill, perhaps on another house, yours does not need one, an older house would be more representative of what this product is designed to resolve.
           
          We have models from 32 CFM to 850 CFM.
          Regards,
           
          John Miggins
          Harvest Solar & Wind Power
          "renewable solutions to everyday needs"
          www.harvest-energy.com
          Phone/Fax 918-743-2299
          Cell: 918-521-6223
          ----- Original Message -----
          Sent: Sunday, December 12, 2004 10:25 PM
          Subject: Re: [hreg] Solar Attic Fans OPPS

          John:
           
          See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 
           
          LaVerne A. Williams, AIA, LEED AP
          architect & building ecologist
          LaVerne@...
          ENVIRONMENT ASSOCIATES, Architects & Consultants
          5828 Langfield Road
          Houston, TX 77092-1429
          713.528.0000
          866.815.2527 toll free
          www.environmentassoc.com
          30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
          Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
          ----- Original Message -----
          Sent: Sunday, December 12, 2004 5:30 PM
          Subject: Re: [hreg] Solar Attic Fans OPPS

          Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)
           
           It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)
          I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
           
           Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 
          I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
           
           
          Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston, as there were tens of thousands, if not more, installed.)
           
          We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)
           
          regards
           
           
          John Miggins
          Harvest Solar & Wind Power
          "renewable solutions to everyday needs"
          www.harvest-energy.com
          Phone/Fax 918-743-2299
          Cell: 918-521-6223
          ----- Original Message -----
          Sent: Sunday, December 12, 2004 1:06 PM
          Subject: Re: [hreg] Solar Attic Fans OPPS

          Opps.    Please see my correction/comments below in GREEN to my original email.
           
          LaVerne
          ----- Original Message -----
          Sent: Sunday, December 12, 2004 12:29 PM
          Subject: Re: [hreg] Solar Attic Fans

          Mike:
           
          Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
           
          (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
           
          Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
           
          If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
           
          Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
           
          Hope this helps. 
           
          LaVerne A. Williams, AIA, LEED AP
          architect & building ecologist
          LaVerne@...
          ENVIRONMENT ASSOCIATES, Architects & Consultants
          5828 Langfield Road
          Houston, TX 77092-1429
          713.528.0000
          866.815.2527 toll free
          www.environmentassoc.com
          30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
          Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
           
          **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
           
           
           
          ----- Original Message -----
          Sent: Saturday, December 11, 2004 7:20 PM
          Subject: [hreg] Solar Attic Fans

          Hello,

           

          I guess I have to start somewhere..So I will start with attic fans.

           

          I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

           

          Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

           

          Some questions I have are:

           

          1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
          2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
          3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
          4. Anything else I’m missing?

           

          Thanks in advance for your time!!!

           

          Mike Schmitt

           

           

           

           



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        • David Power
          John do you have a vent designed for tile roofs? Everything I ve run across seems to be designed for a composite roof. I know that I can build a box for the
          Message 4 of 17 , Dec 13, 2004
            John do you have a vent designed for tile roofs? Everything I've run across seems to be designed for a composite roof. I know that I can build a box for the fan to sit on top of and have the tile cut to fit around it but the cost of the install exceeds the cost of the fan by quite a bit and I worry about leaks.
             
            David
             
            ----- Original Message -----
            Sent: Sunday, December 12, 2004 5:30 PM
            Subject: Re: [hreg] Solar Attic Fans OPPS

            Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.  I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good.  Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.
             
             It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.
            I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
             
             Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge.
             
            I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
             
             
            Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.
             
            We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.
             
            regards
             
             
            John Miggins
            Harvest Solar & Wind Power
            "renewable solutions to everyday needs"
            www.harvest-energy.com
            Phone/Fax 918-743-2299
            Cell: 918-521-6223
            ----- Original Message -----
            Sent: Sunday, December 12, 2004 1:06 PM
            Subject: Re: [hreg] Solar Attic Fans OPPS

            Opps.    Please see my correction/comments below in GREEN to my original email.
             
            LaVerne
            ----- Original Message -----
            Sent: Sunday, December 12, 2004 12:29 PM
            Subject: Re: [hreg] Solar Attic Fans

            Mike:
             
            Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
             
            (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
             
            Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
             
            If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
             
            Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
             
            Hope this helps. 
             
            LaVerne A. Williams, AIA, LEED AP
            architect & building ecologist
            LaVerne@...
            ENVIRONMENT ASSOCIATES, Architects & Consultants
            5828 Langfield Road
            Houston, TX 77092-1429
            713.528.0000
            866.815.2527 toll free
            www.environmentassoc.com
            30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
            Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
             
            **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
             
             
             
            ----- Original Message -----
            Sent: Saturday, December 11, 2004 7:20 PM
            Subject: [hreg] Solar Attic Fans

            Hello,

             

            I guess I have to start somewhere..So I will start with attic fans.

             

            I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

             

            Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

             

            Some questions I have are:

             

            1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
            2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
            3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
            4. Anything else I’m missing?

             

            Thanks in advance for your time!!!

             

            Mike Schmitt

             

             

             

             



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            Checked by AVG anti-virus system (http://www.grisoft.com).
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          • SBT Designs
            Laverne, Considering the power source for any solar product is Sun energy that we don t pay for, how can you say the return on investment does not exist for
            Message 5 of 17 , Dec 13, 2004
              Laverne,
               
              Considering the power source for any solar product is Sun energy that we don't pay for, how can you say the return on investment does not exist for using a solar product in this application or any application?  It seems to me that if a solar fan runs for five, ten, fifteen years then the return of investment would be realized several times.
               
              SBT Designs
              25581 IH-10 West
              San Antonio, Texas 78257
              (210) 698-7109
              www.sbtdesigns.com
              ----- Original Message -----
              Sent: Sunday, December 12, 2004 10:25 PM
              Subject: Re: [hreg] Solar Attic Fans OPPS

              John:
               
              See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 
               
              LaVerne A. Williams, AIA, LEED AP
              architect & building ecologist
              LaVerne@...
              ENVIRONMENT ASSOCIATES, Architects & Consultants
              5828 Langfield Road
              Houston, TX 77092-1429
              713.528.0000
              866.815.2527 toll free
              www.environmentassoc.com
              30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
              Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
              ----- Original Message -----
              Sent: Sunday, December 12, 2004 5:30 PM
              Subject: Re: [hreg] Solar Attic Fans OPPS

              Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)
               
               It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)
              I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
               
               Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 
              I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
               
               
              Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston, as there were tens of thousands, if not more, installed.)
               
              We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)
               
              regards
               
               
              John Miggins
              Harvest Solar & Wind Power
              "renewable solutions to everyday needs"
              www.harvest-energy.com
              Phone/Fax 918-743-2299
              Cell: 918-521-6223
              ----- Original Message -----
              Sent: Sunday, December 12, 2004 1:06 PM
              Subject: Re: [hreg] Solar Attic Fans OPPS

              Opps.    Please see my correction/comments below in GREEN to my original email.
               
              LaVerne
              ----- Original Message -----
              Sent: Sunday, December 12, 2004 12:29 PM
              Subject: Re: [hreg] Solar Attic Fans

              Mike:
               
              Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
               
              (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
               
              Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
               
              If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
               
              Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
               
              Hope this helps. 
               
              LaVerne A. Williams, AIA, LEED AP
              architect & building ecologist
              LaVerne@...
              ENVIRONMENT ASSOCIATES, Architects & Consultants
              5828 Langfield Road
              Houston, TX 77092-1429
              713.528.0000
              866.815.2527 toll free
              www.environmentassoc.com
              30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
              Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
               
              **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
               
               
               
              ----- Original Message -----
              Sent: Saturday, December 11, 2004 7:20 PM
              Subject: [hreg] Solar Attic Fans

              Hello,

               

              I guess I have to start somewhere..So I will start with attic fans.

               

              I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

               

              Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

               

              Some questions I have are:

               

              1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
              2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
              3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
              4. Anything else I’m missing?

               

              Thanks in advance for your time!!!

               

              Mike Schmitt

               

               

               

               



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              Outgoing mail is certified Virus Free.
              Checked by AVG anti-virus system (http://www.grisoft.com).
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            • SBT Designs
              For tile roofs or any roofs you want to avoid making penetrations into you might consider the solar gable fan kits. They are much easier to install. SBT
              Message 6 of 17 , Dec 13, 2004
                For tile roofs or any roofs you want to avoid making penetrations into you might consider the solar gable fan kits.  They are much easier to install.
                 
                SBT Designs
                25581 IH-10 West
                San Antonio, Texas 78257
                (210) 698-7109
                www.sbtdesigns.com
                ----- Original Message -----
                Sent: Monday, December 13, 2004 10:50 AM
                Subject: Re: [hreg] Solar Attic Fans OPPS

                John do you have a vent designed for tile roofs? Everything I've run across seems to be designed for a composite roof. I know that I can build a box for the fan to sit on top of and have the tile cut to fit around it but the cost of the install exceeds the cost of the fan by quite a bit and I worry about leaks.
                 
                David
                 
                ----- Original Message -----
                Sent: Sunday, December 12, 2004 5:30 PM
                Subject: Re: [hreg] Solar Attic Fans OPPS

                Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.  I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good.  Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.
                 
                 It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.
                I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
                 
                 Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge.
                 
                I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
                 
                 
                Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.
                 
                We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.
                 
                regards
                 
                 
                John Miggins
                Harvest Solar & Wind Power
                "renewable solutions to everyday needs"
                www.harvest-energy.com
                Phone/Fax 918-743-2299
                Cell: 918-521-6223
                ----- Original Message -----
                Sent: Sunday, December 12, 2004 1:06 PM
                Subject: Re: [hreg] Solar Attic Fans OPPS

                Opps.    Please see my correction/comments below in GREEN to my original email.
                 
                LaVerne
                ----- Original Message -----
                Sent: Sunday, December 12, 2004 12:29 PM
                Subject: Re: [hreg] Solar Attic Fans

                Mike:
                 
                Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
                 
                (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
                 
                Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
                 
                If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
                 
                Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
                 
                Hope this helps. 
                 
                LaVerne A. Williams, AIA, LEED AP
                architect & building ecologist
                LaVerne@...
                ENVIRONMENT ASSOCIATES, Architects & Consultants
                5828 Langfield Road
                Houston, TX 77092-1429
                713.528.0000
                866.815.2527 toll free
                www.environmentassoc.com
                30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                 
                **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
                 
                 
                 
                ----- Original Message -----
                Sent: Saturday, December 11, 2004 7:20 PM
                Subject: [hreg] Solar Attic Fans

                Hello,

                 

                I guess I have to start somewhere..So I will start with attic fans.

                 

                I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                 

                Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                 

                Some questions I have are:

                 

                1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
                3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                4. Anything else I’m missing?

                 

                Thanks in advance for your time!!!

                 

                Mike Schmitt

                 

                 

                 

                 



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                Outgoing mail is certified Virus Free.
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              • Mike Schmitt
                I did see some that fit on tiles when I searched on the web for attic fans. I will see if I still have the link in my history. The flashing molded around the
                Message 7 of 17 , Dec 13, 2004

                  I did see some that fit on tiles when I searched on the web for attic fans. I will see if I still have the link in my history. The flashing molded around the tiles.

                   

                  Mike

                   

                   


                  From: David Power [mailto:dpower@...]
                  Sent: Monday, December 13, 2004 10:51 AM
                  To: hreg@yahoogroups.com
                  Subject: Re: [hreg] Solar Attic Fans OPPS

                   

                  John do you have a vent designed for tile roofs? Everything I've run across seems to be designed for a composite roof. I know that I can build a box for the fan to sit on top of and have the tile cut to fit around it but the cost of the install exceeds the cost of the fan by quite a bit and I worry about leaks.

                   

                  David

                   

                  ----- Original Message -----

                  Sent: Sunday, December 12, 2004 5:30 PM

                  Subject: Re: [hreg] Solar Attic Fans OPPS

                   

                  Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.  I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good.  Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.

                   

                   It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.

                  I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.

                   

                   Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge.

                   

                  I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 

                   

                   

                  Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.

                   

                  We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.

                   

                  regards

                   

                   

                  John Miggins
                  Harvest Solar & Wind Power
                  "renewable solutions to everyday needs"
                  www.harvest-energy.com
                  Phone/Fax 918-743-2299
                  Cell: 918-521-6223

                  ----- Original Message -----

                  Sent: Sunday, December 12, 2004 1:06 PM

                  Subject: Re: [hreg] Solar Attic Fans OPPS

                   

                  Opps.    Please see my correction/comments below in GREEN to my original email.

                   

                  LaVerne

                  ----- Original Message -----

                  Sent: Sunday, December 12, 2004 12:29 PM

                  Subject: Re: [hreg] Solar Attic Fans

                   

                  Mike:

                   

                  Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston , continuous ridge and soffit ventilation performed best.

                   

                  (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 

                   

                  Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.

                   

                  If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  

                   

                  Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.

                   

                  Hope this helps. 

                   

                  LaVerne A. Williams, AIA, LEED AP
                  architect & building ecologist
                  LaVerne@...
                  ENVIRONMENT ASSOCIATES, Architects & Consultants
                  5828 Langfield Road
                  Houston , TX 77092-1429
                  713.528.0000
                  866.815.2527 toll free
                  www.environmentassoc.com
                  30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                  Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                   

                  **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.

                   

                   

                   

                  ----- Original Message -----

                  Sent: Saturday, December 11, 2004 7:20 PM

                  Subject: [hreg] Solar Attic Fans

                   

                  Hello,

                   

                  I guess I have to start somewhere..So I will start with attic fans.

                   

                  I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                   

                  Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                   

                  Some questions I have are:

                   

                  1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                  2. Where can I get some quality attic fans? What CFM is a good flow to have here in Houston ?
                  3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                  4. Anything else I’m missing?

                   

                  Thanks in advance for your time!!!

                   

                  Mike Schmitt

                   

                   

                   

                   

                   

                  ---
                  Outgoing mail is certified Virus Free.
                  Checked by AVG anti-virus system (http://www.grisoft.com).
                  Version: 6.0.778 / Virus Database: 525 - Release Date: 10/15/2004

                   





                  ---
                  Incoming mail is certified Virus Free.
                  Checked by AVG anti-virus system (http://www.grisoft.com).
                  Version: 6.0.778 / Virus Database: 525 - Release Date: 10/15/2004


                  ---
                  Outgoing mail is certified Virus Free.
                  Checked by AVG anti-virus system (http://www.grisoft.com).
                  Version: 6.0.778 / Virus Database: 525 - Release Date: 10/15/2004

                • John Miggins
                  yes we have a model that includes a flashing that goes under the tiles to prevent leaks. Tiles have to be removed, this flashing installed then the tiles put
                  Message 8 of 17 , Dec 13, 2004
                    yes we have a model that includes a flashing that goes under the tiles to prevent leaks.  Tiles have to be removed, this flashing installed then the tiles put back on cut out over the flashing.  A bit more work but it is doable.  flashing is maleable type of metal that can be formed to correspond to your roof features.
                     
                    The gable mount is also an option to do if you have that, in this case the fan and solar panel are seperate so the panel can be up to 20' away from the fan to optimize the sun.
                     
                    Not sure on the thermal impacts of tile roofs, does your attic get hot?  I would imagine that they are more of an insulator than composition shingles. 
                     
                    regards
                     
                     
                     
                    John Miggins
                    Harvest Solar & Wind Power
                    "renewable solutions to everyday needs"
                    www.harvest-energy.com
                    Phone/Fax 918-743-2299
                    Cell: 918-521-6223
                    ----- Original Message -----
                    Sent: Monday, December 13, 2004 10:50 AM
                    Subject: Re: [hreg] Solar Attic Fans OPPS

                    John do you have a vent designed for tile roofs? Everything I've run across seems to be designed for a composite roof. I know that I can build a box for the fan to sit on top of and have the tile cut to fit around it but the cost of the install exceeds the cost of the fan by quite a bit and I worry about leaks.
                     
                    David
                     
                    ----- Original Message -----
                    Sent: Sunday, December 12, 2004 5:30 PM
                    Subject: Re: [hreg] Solar Attic Fans OPPS

                    Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.  I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good.  Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.
                     
                     It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.
                    I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
                     
                     Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge.
                     
                    I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
                     
                     
                    Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.
                     
                    We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.
                     
                    regards
                     
                     
                    John Miggins
                    Harvest Solar & Wind Power
                    "renewable solutions to everyday needs"
                    www.harvest-energy.com
                    Phone/Fax 918-743-2299
                    Cell: 918-521-6223
                    ----- Original Message -----
                    Sent: Sunday, December 12, 2004 1:06 PM
                    Subject: Re: [hreg] Solar Attic Fans OPPS

                    Opps.    Please see my correction/comments below in GREEN to my original email.
                     
                    LaVerne
                    ----- Original Message -----
                    Sent: Sunday, December 12, 2004 12:29 PM
                    Subject: Re: [hreg] Solar Attic Fans

                    Mike:
                     
                    Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
                     
                    (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
                     
                    Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
                     
                    If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
                     
                    Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
                     
                    Hope this helps. 
                     
                    LaVerne A. Williams, AIA, LEED AP
                    architect & building ecologist
                    LaVerne@...
                    ENVIRONMENT ASSOCIATES, Architects & Consultants
                    5828 Langfield Road
                    Houston, TX 77092-1429
                    713.528.0000
                    866.815.2527 toll free
                    www.environmentassoc.com
                    30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                    Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                     
                    **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
                     
                     
                     
                    ----- Original Message -----
                    Sent: Saturday, December 11, 2004 7:20 PM
                    Subject: [hreg] Solar Attic Fans

                    Hello,

                     

                    I guess I have to start somewhere..So I will start with attic fans.

                     

                    I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                     

                    Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                     

                    Some questions I have are:

                     

                    1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                    2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
                    3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                    4. Anything else I’m missing?

                     

                    Thanks in advance for your time!!!

                     

                    Mike Schmitt

                     

                     

                     

                     



                    ---
                    Outgoing mail is certified Virus Free.
                    Checked by AVG anti-virus system (http://www.grisoft.com).
                    Version: 6.0.778 / Virus Database: 525 - Release Date: 10/15/2004





                  • Naturallighting.com
                    Free building energy simulation program, modeling, heating, cooling,lighting, ventilation, etc. http://www.eere.energy.gov/buildings/energyplus/ Larry Weber
                    Message 9 of 17 , Dec 13, 2004
                      Energy Program Modeling - energyplus simulation solftware

                      Free building energy simulation program, modeling, heating, cooling,lighting, ventilation, etc.

                      http://www.eere.energy.gov/buildings/energyplus/

                      Larry Weber




                      Naturallighting.com
                      1939 Richvale
                      Houston, Texas  77062

                      Toll Free  1.888.900.6830
                      FAX        281.488.0823

                      email:  larry@...
                      http://www.naturallighting.com

                    • David Power
                      The attic doesn t get extremely hot but I would like to keep as close to ambient as possible. The roof was built with cool ply (radiant barrier) but I wasn t
                      Message 10 of 17 , Dec 13, 2004
                        The attic doesn't get extremely hot but I would like to keep as close to ambient as possible. The roof was built with cool ply (radiant barrier) but I wasn't able to find a roofer that would put the roofing membrane that I wanted to use on and warranty the roof. I ended up with one layer of 15# felt and two layers of 30# on top of that with ice and water guard installed in the valley's and on the perimeter. This is not a breathable surface so I want to make sure that the roof stays well ventilated. I have a 2" soffit vent around the perimeter and low profile roof vents scattered around the roof. I had an additional 8 vents installed last summer but still can feel a noticeable difference in the afternoon during the summer heat. The radiant barrier reflects the heat back into the roof surface under the tile so I want to make sure that everything stays nice and cool.
                         
                        David
                         
                         
                        ----- Original Message -----
                        Sent: Monday, December 13, 2004 7:47 PM
                        Subject: Re: [hreg] Solar Attic Fans OPPS

                        yes we have a model that includes a flashing that goes under the tiles to prevent leaks.  Tiles have to be removed, this flashing installed then the tiles put back on cut out over the flashing.  A bit more work but it is doable.  flashing is maleable type of metal that can be formed to correspond to your roof features.
                         
                        The gable mount is also an option to do if you have that, in this case the fan and solar panel are seperate so the panel can be up to 20' away from the fan to optimize the sun.
                         
                        Not sure on the thermal impacts of tile roofs, does your attic get hot?  I would imagine that they are more of an insulator than composition shingles. 
                         
                        regards
                         
                         
                         
                        John Miggins
                        Harvest Solar & Wind Power
                        "renewable solutions to everyday needs"
                        www.harvest-energy.com
                        Phone/Fax 918-743-2299
                        Cell: 918-521-6223
                        ----- Original Message -----
                        Sent: Monday, December 13, 2004 10:50 AM
                        Subject: Re: [hreg] Solar Attic Fans OPPS

                        John do you have a vent designed for tile roofs? Everything I've run across seems to be designed for a composite roof. I know that I can build a box for the fan to sit on top of and have the tile cut to fit around it but the cost of the install exceeds the cost of the fan by quite a bit and I worry about leaks.
                         
                        David
                         
                        ----- Original Message -----
                        Sent: Sunday, December 12, 2004 5:30 PM
                        Subject: Re: [hreg] Solar Attic Fans OPPS

                        Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.  I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good.  Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.
                         
                         It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.
                        I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
                         
                         Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge.
                         
                        I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
                         
                         
                        Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.
                         
                        We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.
                         
                        regards
                         
                         
                        John Miggins
                        Harvest Solar & Wind Power
                        "renewable solutions to everyday needs"
                        www.harvest-energy.com
                        Phone/Fax 918-743-2299
                        Cell: 918-521-6223
                        ----- Original Message -----
                        Sent: Sunday, December 12, 2004 1:06 PM
                        Subject: Re: [hreg] Solar Attic Fans OPPS

                        Opps.    Please see my correction/comments below in GREEN to my original email.
                         
                        LaVerne
                        ----- Original Message -----
                        Sent: Sunday, December 12, 2004 12:29 PM
                        Subject: Re: [hreg] Solar Attic Fans

                        Mike:
                         
                        Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
                         
                        (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
                         
                        Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
                         
                        If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
                         
                        Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
                         
                        Hope this helps. 
                         
                        LaVerne A. Williams, AIA, LEED AP
                        architect & building ecologist
                        LaVerne@...
                        ENVIRONMENT ASSOCIATES, Architects & Consultants
                        5828 Langfield Road
                        Houston, TX 77092-1429
                        713.528.0000
                        866.815.2527 toll free
                        www.environmentassoc.com
                        30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                        Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                         
                        **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
                         
                         
                         
                        ----- Original Message -----
                        Sent: Saturday, December 11, 2004 7:20 PM
                        Subject: [hreg] Solar Attic Fans

                        Hello,

                         

                        I guess I have to start somewhere..So I will start with attic fans.

                         

                        I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                         

                        Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                         

                        Some questions I have are:

                         

                        1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                        2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
                        3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                        4. Anything else I’m missing?

                         

                        Thanks in advance for your time!!!

                         

                        Mike Schmitt

                         

                         

                         

                         



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                      • Environment Associates Architects
                        Hi Steven: UhOh. I see that there is a misunderstanding about what I said in my email. Where you got that I said or even implied that a return on investment
                        Message 11 of 17 , Dec 13, 2004
                          Hi Steven:
                           
                          UhOh.  I see that there is a misunderstanding about what I said in my email.  Where you got that I said or even implied that a return on investment did not exist for solar power is beyond me. 
                           
                          I stand behind everything I said.  All I am asking for is proof verifying what is being claimed.  Actual studies that verify that solar powered attic fans work better and are a better investment than passive solar ventilation systems like continuous ridge vents with balanced soffit venting.  As I stated in my email, provide the proof and I will be an advocate of the technology.  So far I haven't seen or heard any proof, just what seems like sales talk and literature by manufacturers and resellers that sounds convincing on the surface.  I know the PV cells will outlast the life of a composition shingle roof, but what about the fan?  How long will the fans actually last in an environment having elevated temperatures?  Can replacement fans be easily purchased?  What is the cost to remove and replace the fans? 
                           
                          I am sure there are lots of applications where solar attic fans may be a good solution.  One of these may be where it may not be cost effective to install continuous ridge vents is on a ten year old composition shingle roof, because the ridge vents will have to be ripped off in 5 years or so (Houston climate conditions) and replaced because the roof will need to be replaced.  Another application may be very complicated roof shapes.
                           
                          Everything has its application.  As an advocate for solar energy applications since the 70's (along with being a founding member of TXSES & TREIA, I was one of the founders of another non-profit solar energy society that predated both TXSES & TREIA), I want to see solar power shine as much as anyone else does.  But I need verification of the claims that are being made.  I think it is best for the long term interest of Complimentary Energy Systems.  (UhOh, I'm sure to get comments on this!!!!!)
                           
                          Here are a couple of web sites that may be of interest to those following this discourse:
                           
                          http://www.fsec.ucf.edu/bldg/pubs/pvfan/  This is the kind of documentation I like.....an actual study on the viability of PV powered attic ventilators.  By the way, FSEC also advocates white roofs that may work well in Florida but most will mildew here (Houston) (It's that grayish black stuff that covers composition shingle roofs of all colors here, but shows up most on those that are the lighter colored.  If you can find composition shingle roofing having lots of zinc granules, the leaching out of the zinc will kill mold spores before they can grow like below most vent pipes and turbine ventilators where they poke through composition shingle roofs here.  Manufacturers' make such roofs, but in the past no one was willing to order a box car load (minimum order) of them to sell in Houston.) 
                           
                           
                           
                          LaVerne A. Williams, AIA, LEED AP
                          architect & building ecologist
                          LaVerne@...
                          ENVIRONMENT ASSOCIATES, Architects & Consultants
                          5828 Langfield Road
                          Houston, TX 77092-1429
                          713.528.0000
                          866.815.2527 toll free
                          www.environmentassoc.com
                          30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                          Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                           
                           
                           
                           
                          ----- Original Message -----
                          Sent: Monday, December 13, 2004 12:15 PM
                          Subject: Re: [hreg] Solar Attic Fans OPPS

                          Laverne,
                           
                          Considering the power source for any solar product is Sun energy that we don't pay for, how can you say the return on investment does not exist for using a solar product in this application or any application?  It seems to me that if a solar fan runs for five, ten, fifteen years then the return of investment would be realized several times.
                           
                          SBT Designs
                          25581 IH-10 West
                          San Antonio, Texas 78257
                          (210) 698-7109
                          www.sbtdesigns.com
                          ----- Original Message -----
                          Sent: Sunday, December 12, 2004 10:25 PM
                          Subject: Re: [hreg] Solar Attic Fans OPPS

                          John:
                           
                          See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 
                           
                          LaVerne A. Williams, AIA, LEED AP
                          architect & building ecologist
                          LaVerne@...
                          ENVIRONMENT ASSOCIATES, Architects & Consultants
                          5828 Langfield Road
                          Houston, TX 77092-1429
                          713.528.0000
                          866.815.2527 toll free
                          www.environmentassoc.com
                          30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                          Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                          ----- Original Message -----
                          Sent: Sunday, December 12, 2004 5:30 PM
                          Subject: Re: [hreg] Solar Attic Fans OPPS

                          Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)
                           
                           It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)
                          I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.
                           
                           Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 
                          I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 
                           
                           
                          Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston, as there were tens of thousands, if not more, installed.)
                           
                          We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)
                           
                          regards
                           
                           
                          John Miggins
                          Harvest Solar & Wind Power
                          "renewable solutions to everyday needs"
                          www.harvest-energy.com
                          Phone/Fax 918-743-2299
                          Cell: 918-521-6223
                          ----- Original Message -----
                          Sent: Sunday, December 12, 2004 1:06 PM
                          Subject: Re: [hreg] Solar Attic Fans OPPS

                          Opps.    Please see my correction/comments below in GREEN to my original email.
                           
                          LaVerne
                          ----- Original Message -----
                          Sent: Sunday, December 12, 2004 12:29 PM
                          Subject: Re: [hreg] Solar Attic Fans

                          Mike:
                           
                          Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston, continuous ridge and soffit ventilation performed best.
                           
                          (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 
                           
                          Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.
                           
                          If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  
                           
                          Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.
                           
                          Hope this helps. 
                           
                          LaVerne A. Williams, AIA, LEED AP
                          architect & building ecologist
                          LaVerne@...
                          ENVIRONMENT ASSOCIATES, Architects & Consultants
                          5828 Langfield Road
                          Houston, TX 77092-1429
                          713.528.0000
                          866.815.2527 toll free
                          www.environmentassoc.com
                          30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                          Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services
                           
                          **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.
                           
                           
                           
                          ----- Original Message -----
                          Sent: Saturday, December 11, 2004 7:20 PM
                          Subject: [hreg] Solar Attic Fans

                          Hello,

                           

                          I guess I have to start somewhere..So I will start with attic fans.

                           

                          I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                           

                          Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                           

                          Some questions I have are:

                           

                          1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                          2. Where can I get some quality attic fans? What CFM is a good flow to have here inHouston ?
                          3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                          4. Anything else I’m missing?

                           

                          Thanks in advance for your time!!!

                           

                          Mike Schmitt

                           

                           

                           

                           



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                        • Environment Associates Architects
                          Paul: I have put my comments where they are within the body of John Miggins text in HTML and in paranthesis so they will stand apart from the rest. Hope this
                          Message 12 of 17 , Dec 13, 2004
                            Paul:

                            I have put my comments where they are within the body of John Miggins text
                            in HTML and in paranthesis so they will stand apart from the rest.

                            Hope this helps. I wasn't aware of your situation.

                            LaVerne


                            ----- Original Message -----
                            From: Environment Associates Architects
                            To: hreg@yahoogroups.com
                            Sent: Sunday, December 12, 2004 10:25 PM
                            Subject: Re: [hreg] Solar Attic Fans OPPS


                            John:

                            See my comments in (paranthesis) below. Also, what most people may not
                            realize is that I don't sell any construction products, building equipment,
                            solar, alternative or conventional energy products, so there is no vested
                            interest in the recommendations I make. In other words, I don't make any
                            profit from the sale of the stuff I recommend. Nor do I accept any
                            "referral fee" compensation from those who do manufacturer or sell the
                            products I make in my recommendations. I do this because I want all of my
                            clients to know I am looking out for their best interests, not how much
                            money I might pocket from what I recommend for their particular situation.
                            If for some reason you don't think I am up to date with what is available
                            out there, please educate me, as I would want my clients (and subsequently
                            you) to benefit from superior technology and design.

                            LaVerne A. Williams, AIA, LEED AP
                            architect & building ecologist
                            LaVerne@...
                            ENVIRONMENT ASSOCIATES, Architects & Consultants
                            5828 Langfield Road
                            Houston, TX 77092-1429
                            713.528.0000
                            866.815.2527 toll free
                            www.environmentassoc.com
                            30 Years of Leadership in Healthy, High Performance Homes / Green
                            Architecture
                            Design Counseling / Consulting / Architectural Design / Construction
                            Documents / Construction Administration Services
                            ----- Original Message -----
                            From: John Miggins
                            To: hreg@yahoogroups.com
                            Sent: Sunday, December 12, 2004 5:30 PM
                            Subject: Re: [hreg] Solar Attic Fans OPPS


                            Mike, we install lots of solar powered attic fans and I can tell you that
                            they do save you money because they have no ongoing cost to run and reduce
                            the attic temperature of homes from 20 to 30 degrees.

                            (But there is initial cost and lifecycle cost issues. What is their life
                            span?) Show me the tests that prove this much temperature drop along with
                            acceptable life cycle costs and I will become an advocate of solar powered
                            attic ventilation fans.)

                            I don't see how this cannot save you money on cooling your home in the
                            summer. It also helps reduce moisture in the attic which can cause other
                            problems.

                            (Let's think about this. Generally, let's hope the air outside the attic is
                            more humid than the air already in the attic, (an exception perhaps being
                            after a dry cold front comes through) otherwise there is a basic
                            construction or operation problem here. So I don't see how bringing in more
                            humid outside air is going to make the attic less humid.)

                            Soffit vents to create bottom to top air flow are essential. My experience
                            with ridge vents and soffet vents is that if there is not a suction or motor
                            pulling the air out they do very little good.

                            (That's the beauty of passive ventilation systems. They work by creating a
                            laminar-like flow below the roof deck that is spread out over a large area.
                            Plus it is removing the hottest air....the air right below the roof deck.
                            It's not like measuring the concentrated flow of air near a fan. Passive
                            ridge vents don't require any generated energy to run them, solar or
                            otherwise, other than the heat of the sun on the roof to create a thermal
                            chimney effect, i.e., hot air rises to create a draft. This draft is
                            enhanced when there is a breeze and the flow of the breeze over the ridges
                            creates a suction throught the Venturi effect.)

                            Take a cigarette in the attic and check air flow before and after attic
                            fans, it is a good way to test real world conditions.

                            (When I did smoke a long time ago, I could always show my clients how the
                            draft was working with ridge & soffit vents. The only time it didn't was
                            when the ridge and soffit vents were not installed properly.......or it was
                            nighttime.)


                            It is common sense and I don't know if they were talking about attic fans
                            that ventillate from the living space or from the attic in the mentioned
                            study but if you have a 130 degree oven (your unventillated attic) over your
                            living space and most homes have their AC vents running through this hot
                            space that this heat transfers to your living space and to your AC. I
                            personally have measured the temp of the air coming out of AC vents in
                            attics and have seen a 2 to 3 degree difference within hours of installing
                            solar attic fans.

                            (2 or 3 degrees? You said 20 to 30 degrees in your 1st sentence. Which is
                            it?)


                            I have also had customers tell me that they used to keep thermostats at 74
                            and now, with attic fans and a cooler attic can keep their thermostat at 77.
                            Several repeat sales.
                            Not sure that solar attic (crawl space) ventillation units were around in
                            the 70's so not sure what was included in the aforementioned study 35 years
                            ago but I have hundreds of customers that will testify that they are a good
                            investment and have reduced their electric bill, especially in the summer.

                            (They weren't available then. Especially if there is a moisture problem with
                            a crawl space, this is a good application. However, the source of the
                            moisture should be addressed and eliminated if possible due to health
                            concerns)

                            We put thermostats on the solar attic fans to cut on at 80 degrees and cut
                            off at 70 to save heat in the winter. You be the judge.
                            I agree that radiant barrier is a good investment as well, keep the heat out
                            in the first place and keeps your heat in.
                            Solar hot water can interface with existing water heaters by adding a
                            preheat tank that captures the hot solution from the roof panels (located in
                            the sun) and preheats the cold water going into your existing water heater.
                            It is better to add a new tank as well but that is not necessary.

                            (I concur. I especially like passive solar water heating systems that
                            include the storage tank. No freeze concerns as long as the solar collector
                            has a drain down provision. They do present some structural concerns and may
                            require some additional support. I do not, however, recommend mounting any
                            type of solar system on a composition shingle roof, because of the roof will
                            have to be replaced long before the solar system and removing and
                            reinstalling a solar system is too costly for most folks. This is the main
                            reason why you don't see any solar systems from the 70's & 80's still on
                            rooftops in Houston, as there were tens of thousands, if not more,
                            installed.)


                            We have units in stock if you are interested contact me offline they are
                            easy to install yourself if needed. Houston is an ideal market for this as
                            it is hot 8 months out of the year. (Did you purchase David Sawchak's
                            stock?)
                            regards
                            John Miggins
                            Harvest Solar & Wind Power
                            "renewable solutions to everyday needs"
                            www.harvest-energy.com
                            Phone/Fax 918-743-2299
                            Cell: 918-521-6223
                            ----- Original Message -----
                            From: Environment Associates Architects
                            To: hreg@yahoogroups.com
                            Sent: Sunday, December 12, 2004 1:06 PM
                            Subject: Re: [hreg] Solar Attic Fans OPPS
                            Opps. Please see my correction/comments below in ALL CAPS to my original
                            email.
                            LaVerne
                            ----- Original Message -----
                            From: Environment Associates Architects
                            To: hreg@yahoogroups.com
                            Sent: Sunday, December 12, 2004 12:29 PM
                            Subject: Re: [hreg] Solar Attic Fans
                            Mike:
                            Back in the 70's, a study was done in Houston by HUD (I think) regarding
                            attic fans versus other types of attic ventilation and the results came back
                            showing the

                            energy saved

                            (in air conditioned homes) by attic ventilation fans for removing heat
                            didn't offset the amount of energy they used. So this study showed there was
                            no advantage to powered attic ventilation. This would also apply to PV
                            powered attic ventilation fans. It clearly showed that when it came to
                            ventilating attics in Houston, continuous ridge and soffit ventilation
                            performed best.
                            (Assuming you are using gas for heating** and that your furnace is located
                            in the attic where it needs combustion air supply from outside), continuous
                            ridge vents balanced with soffit ventilation proportionally located around
                            the entire perimeter of your house is your best option. If you have hip
                            roofs, you will have to run the ridge vents down the hips. I would use
                            Cor-A-Vent for the ridge and hip vents, following details you can get from
                            their website. The soffits vents can be any kind (even galvanized hardware
                            cloth). They must can be sized to balance the air admittance into the attic
                            so that the free inflow air flow area is equal to or greater than the free
                            exit area of the ridge vent area. In other words, don't put twice as much
                            soffit venting on the west side versus the east side of your roof. It has to
                            be evenly balanced around the house. Otherwise, you can get water intrusion
                            into your attic during blowing rains, not matter whose ridge vent system is
                            used.
                            Also, be sure to include insulation baffles in your plans so that the air
                            path from the soffit vents to the ridge vents isn't blocked by insulation.
                            If your house is all electric, you may want to consider insulating at the
                            roof and eliminating attic ventilation all together, as a lot of moisture is
                            added to the interior of your house from having ventilated attics. In this
                            area of the country, approx. half of your air-conditioning bill comes from
                            just removing the moisture for the air. While all this moisture obviously
                            doesn't just come through your ceilings, sheet rock and insulation are not
                            going to stop attic moisture from diffusing down into the interior space. So
                            eliminating the moisture from this source will not only help reduce your
                            energy bill, but can also provide a healthier indoor environment. Since dust
                            mites and molds thrive in high humidity environments, eliminating as many
                            possible sources for humidity intrusion into the interior of our homes is
                            prudent. However, insulating at the underside of the roof will cost more
                            initially.
                            Should you follow the ventilated attic path, if you haven't already stapled
                            a radiant barrier to the underside of your rafters or considered some other
                            means for adding a radiant barrier to the underside of your roof, it should
                            be considered a major component in your strategy to improve your home's
                            performance. If you decide to insulate with spray-in foam insulation on the
                            underside of the roof deck, then disregard the use of the radiant barrier.
                            Hope this helps.
                            LaVerne A. Williams, AIA, LEED AP
                            architect & building ecologist
                            LaVerne@...
                            ENVIRONMENT ASSOCIATES, Architects & Consultants
                            5828 Langfield Road
                            Houston, TX 77092-1429
                            713.528.0000
                            866.815.2527 toll free
                            www.environmentassoc.com
                            30 Years of Leadership in Healthy, High Performance Homes / Green
                            Architecture
                            Design Counseling / Consulting / Architectural Design / Construction
                            Documents / Construction Administration Services

                            **If the water heater is gas, make sure you don't eliminate it's outside air
                            supply for combustion in your insulation /attic sealing efforts.

                            ----- Original Message -----
                            From: Mike Schmitt
                            To: hreg@yahoogroups.com
                            Sent: Saturday, December 11, 2004 7:20 PM
                            Subject: [hreg] Solar Attic Fans
                            Hello,
                            I guess I have to start somewhere..So I will start with attic fans.
                            I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see
                            the old style turbines spin on my roof. I have added more sofit vents and
                            still doesn’t seem to get them moving. So instead of replacing the turbins
                            with new ones, Im looking into changing them out with 2 solar powered attic
                            fans to help cool down the attic. I’m trying to find small PV projects to
                            start with and work up to the bigger ones later after I get the house better
                            insulated.
                            Right now this 2 story house is 2200 sq feet with the highest electric bill
                            was at $134.00 this summer. I have been graphing my daily power usage and
                            the highest was 82 KWh for one day. All the bulbs have been replaced with
                            the Compact FL bulbs (60w version). The attic has to have more insulation
                            added. I was able to get insulation in 30% of the attic this summer. All the
                            A/C ducts are in the way…will finish up this winter. The windows in this
                            house are a step above the aluminum frame. They have double panes but are
                            worthless….they will have to be updated soon. The good thing about this
                            house is that the previous owner paid the money to have the interior walls
                            insulated as well as the exterior but for some reason did a half rear job in
                            the attic. The 30% I put in up there was to cover the corner that didn’t
                            have any. After updating some appliances (washer/dryer, fridge and dish
                            washer) I should be able to move up to the bigger projects.
                            Some questions I have are:
                            At what point (daily KWh usage) is a good point to start adding PV systems.
                            Im thinking in terms of a hobby because off the A/C systems in Houston… you
                            can’t really go off grid or can you? How does it work with the A/C power
                            usage?
                            Where can I get some quality attic fans? What CFM is a good flow to have
                            here in Houston?
                            Any Ideas on how to hook up a solar water heater that has the water heater
                            situated on the first floor in the middle of the house? Can I use a plain
                            insulated tank in the attic or do I need to tie into another water heater?
                            Anything else I’m missing?
                            Thanks in advance for your time!!!
                            Mike Schmitt







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                          • Andrew McCalla
                            Well folks, Consider this a submission of a third party s results. In brief, it would seem that while pv vent fans can lower attic air temperatures, there are
                            Message 13 of 17 , Dec 14, 2004

                              Well folks,

                               

                              Consider this a submission of a third party’s results.

                               

                              In brief, it would seem that while pv vent fans can lower attic air temperatures, there are better ways to achieve the effects of this reduction, some of which would also have positive winter-time ramifications. 

                               

                              http://www.fsec.ucf.edu/bldg/pubs/pvfan/index.htm

                               

                              Another report which touches on this matter (although dealing specifically with AC powered vent fans, does address attic cooling in general):

                               

                              http://www.fsec.ucf.edu/Pubs/EnergyNotes/en-13.htm#attic

                               

                               

                              Andrew H. McCalla

                              Meridian Energy Systems

                              2300 S. Lamar, Ste. 107

                              Austin, TX   78704

                               

                              Voice: (512) 448-0055

                              Fax:    (512) 448-0045

                              www.meridiansolar.com

                               

                            • Andrew McCalla
                              Oops, Sorry folks. I didn t read down far enough to realize that LaVerne had already done the research...... http://www.fsec.ucf.edu/bldg/pubs/pvfan/ This
                              Message 14 of 17 , Dec 15, 2004

                                Oops,

                                 

                                Sorry folks.  I didn’t read down far enough to realize that LaVerne had already done the research…………..

                                 

                                http://www.fsec.ucf.edu/bldg/pubs/pvfan/  This is the kind of documentation I like.....

                                 

                                http://www.advancedenergy.org/buildings/knowledge_library/ventilation/solar_powered_attic_ventilation.html

                                 

                                 

                                Sorry about the repetition.

                                 

                                 

                                Andrew H. McCalla

                                Meridian Energy Systems

                                2300 S. Lamar, Ste. 107

                                Austin, TX   78704

                                 

                                Voice: (512) 448-0055

                                Fax:    (512) 448-0045

                                www.meridiansolar.com

                                 

                                 

                                 


                                From: Environment Associates Architects [mailto:laverne@...]
                                Sent: Monday, December 13, 2004 11:16 PM
                                To: hreg@yahoogroups.com
                                Subject: Re: [hreg] Solar Attic Fans OPPS

                                 

                                Hi Steven:

                                 

                                UhOh.  I see that there is a misunderstanding about what I said in my email.  Where you got that I said or even implied that a return on investment did not exist for solar power is beyond me. 

                                 

                                I stand behind everything I said.  All I am asking for is proof verifying what is being claimed.  Actual studies that verify that solar powered attic fans work better and are a better investment than passive solar ventilation systems like continuous ridge vents with balanced soffit venting.  As I stated in my email, provide the proof and I will be an advocate of the technology.  So far I haven't seen or heard any proof, just what seems like sales talk and literature by manufacturers and resellers that sounds convincing on the surface.  I know the PV cells will outlast the life of a composition shingle roof, but what about the fan?  How long will the fans actually last in an environment having elevated temperatures?  Can replacement fans be easily purchased?  What is the cost to remove and replace the fans? 

                                 

                                I am sure there are lots of applications where solar attic fans may be a good solution.  One of these may be where it may not be cost effective to install continuous ridge vents is on a ten year old composition shingle roof, because the ridge vents will have to be ripped off in 5 years or so (Houston climate conditions) and replaced because the roof will need to be replaced.  Another application may be very complicated roof shapes.

                                 

                                Everything has its application.  As an advocate for solar energy applications since the 70's (along with being a founding member of TXSES & TREIA, I was one of the founders of another non-profit solar energy society that predated both TXSES & TREIA), I want to see solar power shine as much as anyone else does.  But I need verification of the claims that are being made.  I think it is best for the long term interest of Complimentary Energy Systems.  (UhOh, I'm sure to get comments on this!!!!!)

                                 

                                Here are a couple of web sites that may be of interest to those following this discourse:

                                 

                                http://www.fsec.ucf.edu/bldg/pubs/pvfan/  This is the kind of documentation I like.....an actual study on the viability of PV powered attic ventilators.  By the way, FSEC also advocates white roofs that may work well in Florida but most will mildew here (Houston) (It's that grayish black stuff that covers composition shingle roofs of all colors here, but shows up most on those that are the lighter colored.  If you can find composition shingle roofing having lots of zinc granules, the leaching out of the zinc will kill mold spores before they can grow like below most vent pipes and turbine ventilators where they poke through composition shingle roofs here.  Manufacturers' make such roofs, but in the past no one was willing to order a box car load (minimum order) of them to sell in Houston .) 

                                 

                                 

                                 

                                LaVerne A. Williams, AIA, LEED AP
                                architect & building ecologist
                                LaVerne@...
                                ENVIRONMENT ASSOCIATES, Architects & Consultants
                                5828 Langfield Road
                                Houston , TX 77092-1429
                                713.528.0000
                                866.815.2527 toll free
                                www.environmentassoc.com
                                30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                 

                                 

                                 

                                 

                                ----- Original Message -----

                                Sent: Monday, December 13, 2004 12:15 PM

                                Subject: Re: [hreg] Solar Attic Fans OPPS

                                 

                                Laverne,

                                 

                                Considering the power source for any solar product is Sun energy that we don't pay for, how can you say the return on investment does not exist for using a solar product in this application or any application?  It seems to me that if a solar fan runs for five, ten, fifteen years then the return of investment would be realized several times.

                                 

                                SBT Designs
                                25581 IH-10 West
                                San Antonio , Texas 78257
                                (210) 698-7109
                                www.sbtdesigns.com

                                ----- Original Message -----

                                Sent: Sunday, December 12, 2004 10:25 PM

                                Subject: Re: [hreg] Solar Attic Fans OPPS

                                 

                                John:

                                 

                                See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 

                                 

                                LaVerne A. Williams, AIA, LEED AP
                                architect & building ecologist
                                LaVerne@...
                                ENVIRONMENT ASSOCIATES, Architects & Consultants
                                5828 Langfield Road
                                Houston , TX 77092-1429
                                713.528.0000
                                866.815.2527 toll free
                                www.environmentassoc.com
                                30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                ----- Original Message -----

                                Sent: Sunday, December 12, 2004 5:30 PM

                                Subject: Re: [hreg] Solar Attic Fans OPPS

                                 

                                Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)

                                 

                                 It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)

                                I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.

                                 

                                 Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 

                                I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 

                                 

                                 

                                Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston , as there were tens of thousands, if not more, installed.)

                                 

                                We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)

                                 

                                regards

                                 

                                 

                                John Miggins
                                Harvest Solar & Wind Power
                                "renewable solutions to everyday needs"
                                www.harvest-energy.com
                                Phone/Fax 918-743-2299
                                Cell: 918-521-6223

                                ----- Original Message -----

                                Sent: Sunday, December 12, 2004 1:06 PM

                                Subject: Re: [hreg] Solar Attic Fans OPPS

                                 

                                Opps.    Please see my correction/comments below in GREEN to my original email.

                                 

                                LaVerne

                                ----- Original Message -----

                                Sent: Sunday, December 12, 2004 12:29 PM

                                Subject: Re: [hreg] Solar Attic Fans

                                 

                                Mike:

                                 

                                Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston , continuous ridge and soffit ventilation performed best.

                                 

                                (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 

                                 

                                Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.

                                 

                                If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  

                                 

                                Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.

                                 

                                Hope this helps. 

                                 

                                LaVerne A. Williams, AIA, LEED AP
                                architect & building ecologist
                                LaVerne@...
                                ENVIRONMENT ASSOCIATES, Architects & Consultants
                                5828 Langfield Road
                                Houston , TX 77092-1429
                                713.528.0000
                                866.815.2527 toll free
                                www.environmentassoc.com
                                30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                 

                                **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.

                                 

                                 

                                 

                                ----- Original Message -----

                                Sent: Saturday, December 11, 2004 7:20 PM

                                Subject: [hreg] Solar Attic Fans

                                 

                                Hello,

                                 

                                I guess I have to start somewhere..So I will start with attic fans.

                                 

                                I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                                 

                                Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                                 

                                Some questions I have are:

                                 

                                1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                                2. Where can I get some quality attic fans? What CFM is a good flow to have here in Houston ?
                                3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                                4. Anything else I’m missing?

                                 

                                Thanks in advance for your time!!!

                                 

                                Mike Schmitt

                                 

                                 

                                 

                                 

                                 

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                              • Andrew McCalla
                                Oops, Sorry folks. I didn t read down far enough to realize that LaVerne had already done the research...... http://www.fsec.ucf.edu/bldg/pubs/pvfan/ This
                                Message 15 of 17 , Dec 15, 2004

                                   

                                  Oops,

                                   

                                  Sorry folks.  I didn’t read down far enough to realize that LaVerne had already done the research…………..

                                   

                                  http://www.fsec.ucf.edu/bldg/pubs/pvfan/  This is the kind of documentation I like.....

                                   

                                  http://www.advancedenergy.org/buildings/knowledge_library/ventilation/solar_powered_attic_ventilation.html

                                   

                                   

                                  Sorry about the repetition.

                                   

                                   

                                  Andrew H. McCalla

                                  Meridian Energy Systems

                                  2300 S. Lamar, Ste. 107

                                  Austin, TX   78704

                                   

                                  Voice: (512) 448-0055

                                  Fax:    (512) 448-0045

                                  www.meridiansolar.com

                                   

                                   

                                   


                                  From: Environment Associates Architects [mailto:laverne@...]
                                  Sent: Monday, December 13, 2004 11:16 PM
                                  To: hreg@yahoogroups.com
                                  Subject: Re: [hreg] Solar Attic Fans OPPS

                                   

                                  Hi Steven:

                                   

                                  UhOh.  I see that there is a misunderstanding about what I said in my email.  Where you got that I said or even implied that a return on investment did not exist for solar power is beyond me. 

                                   

                                  I stand behind everything I said.  All I am asking for is proof verifying what is being claimed.  Actual studies that verify that solar powered attic fans work better and are a better investment than passive solar ventilation systems like continuous ridge vents with balanced soffit venting.  As I stated in my email, provide the proof and I will be an advocate of the technology.  So far I haven't seen or heard any proof, just what seems like sales talk and literature by manufacturers and resellers that sounds convincing on the surface.  I know the PV cells will outlast the life of a composition shingle roof, but what about the fan?  How long will the fans actually last in an environment having elevated temperatures?  Can replacement fans be easily purchased?  What is the cost to remove and replace the fans? 

                                   

                                  I am sure there are lots of applications where solar attic fans may be a good solution.  One of these may be where it may not be cost effective to install continuous ridge vents is on a ten year old composition shingle roof, because the ridge vents will have to be ripped off in 5 years or so (Houston climate conditions) and replaced because the roof will need to be replaced.  Another application may be very complicated roof shapes.

                                   

                                  Everything has its application.  As an advocate for solar energy applications since the 70's (along with being a founding member of TXSES & TREIA, I was one of the founders of another non-profit solar energy society that predated both TXSES & TREIA), I want to see solar power shine as much as anyone else does.  But I need verification of the claims that are being made.  I think it is best for the long term interest of Complimentary Energy Systems.  (UhOh, I'm sure to get comments on this!!!!!)

                                   

                                  Here are a couple of web sites that may be of interest to those following this discourse:

                                   

                                  http://www.fsec.ucf.edu/bldg/pubs/pvfan/  This is the kind of documentation I like.....an actual study on the viability of PV powered attic ventilators.  By the way, FSEC also advocates white roofs that may work well in Florida but most will mildew here (Houston) (It's that grayish black stuff that covers composition shingle roofs of all colors here, but shows up most on those that are the lighter colored.  If you can find composition shingle roofing having lots of zinc granules, the leaching out of the zinc will kill mold spores before they can grow like below most vent pipes and turbine ventilators where they poke through composition shingle roofs here.  Manufacturers' make such roofs, but in the past no one was willing to order a box car load (minimum order) of them to sell in Houston .) 

                                   

                                   

                                   

                                  LaVerne A. Williams, AIA, LEED AP
                                  architect & building ecologist
                                  LaVerne@...
                                  ENVIRONMENT ASSOCIATES, Architects & Consultants
                                  5828 Langfield Road
                                  Houston , TX 77092-1429
                                  713.528.0000
                                  866.815.2527 toll free
                                  www.environmentassoc.com
                                  30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                  Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                   

                                   

                                   

                                   

                                  ----- Original Message -----

                                  Sent: Monday, December 13, 2004 12:15 PM

                                  Subject: Re: [hreg] Solar Attic Fans OPPS

                                   

                                  Laverne,

                                   

                                  Considering the power source for any solar product is Sun energy that we don't pay for, how can you say the return on investment does not exist for using a solar product in this application or any application?  It seems to me that if a solar fan runs for five, ten, fifteen years then the return of investment would be realized several times.

                                   

                                  SBT Designs
                                  25581 IH-10 West
                                  San Antonio , Texas 78257
                                  (210) 698-7109
                                  www.sbtdesigns.com

                                  ----- Original Message -----

                                  Sent: Sunday, December 12, 2004 10:25 PM

                                  Subject: Re: [hreg] Solar Attic Fans OPPS

                                   

                                  John:

                                   

                                  See my comments in green below.  Also, what most people may not realize is that I don't sell any construction products, building equipment, solar, alternative or conventional energy products, so there is no vested interest in the recommendations I make.  In other words, I don't make any profit from the sale of the stuff I recommend.  Nor do I accept any "referral fee"  compensation from those who do manufacturer or sell the products I make in my recommendations.  I do this because I want all of my clients to know I am looking out for their best interests, not how much money I might pocket from what I recommend for their particular situation.  If for some reason you don't think I am up to date with what is available out there, please educate me, as I would want my clients (and subsequently you) to benefit from superior technology and design. 

                                   

                                  LaVerne A. Williams, AIA, LEED AP
                                  architect & building ecologist
                                  LaVerne@...
                                  ENVIRONMENT ASSOCIATES, Architects & Consultants
                                  5828 Langfield Road
                                  Houston , TX 77092-1429
                                  713.528.0000
                                  866.815.2527 toll free
                                  www.environmentassoc.com
                                  30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                  Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                  ----- Original Message -----

                                  Sent: Sunday, December 12, 2004 5:30 PM

                                  Subject: Re: [hreg] Solar Attic Fans OPPS

                                   

                                  Mike, we install lots of SOLAR powered attic fans and I can tell you that they do save you money because they have no ongoing cost to run and reduce the attic temperature of homes from 20 to 30 degrees.(But there is initial cost and lifecycle cost issues.  What is their life span?)  Show me the tests that prove this much temperature drop along with acceptable life cycle costs and I will become an advocate of solar powered attic ventilation fans.)    I don't see how this cannot save you money on cooling your home in the summer.  It also helps reduce moisture in the attic which can cause other problems. (Let's think about this.  Generally, let's hope the air outside the attic is more humid than the air already in the attic, (an exception perhaps being after a dry cold front comes through) otherwise there is a basic construction or operation problem here.  So I don't see how bringing in more humid outside air is going to make the attic less humid.)  Soffit vents to create bottom to top air flow are essential.  My experience with ridge vents and soffet vents is that if there is not a suction or motor pulling the air out they do very little good. (That's the beauty of passive ventilation systems.  They work by creating a laminar-like flow below the roof deck that is spread out over a large area.  Plus it is removing the hottest air....the air right below the roof deck.  It's not like measuring the concentrated flow of air near a fan. Passive ridge vents don't require any generated energy to run them, solar or otherwise, other than the heat of the sun on the roof to create a thermal chimney effect, i.e., hot air rises to create a draft.  This draft is enhanced when there is a breeze and the flow of the breeze over the ridges creates a suction throught the Venturi effect.)   Take a cigarette in the attic and check air flow before and after attic fans, it is a good way to test real world conditions.  (When I did smoke a long time ago, I could always show my clients how the draft was working with ridge & soffit vents.  The only time it didn't was when the ridge and soffit vents were not installed properly.......or it was nighttime.)

                                   

                                   It is common sense and I don't know if they were talking about attic fans that ventillate from the living space or from the attic in the mentioned study but if you have a 130 degree oven (your unventillated attic) over your living space and most homes have their AC vents running through this hot space that this heat transfers to your living space and to your AC.  I personally have measured the temp of the air coming out of AC vents in attics and have seen a 2 to 3 degree difference within hours of installing solar attic fans.  (2 or 3 degrees?  You said 20 to 30 degrees in your 1st sentence.  Which is it?)

                                  I have also had customers tell me that they used to keep thermostats at 74 and now, with attic fans and a cooler attic can keep their thermostat at 77.  Several repeat sales.

                                   

                                   Not sure that solar attic (crawl space) ventillation units were around in the 70's so not sure what was included in the aforementioned study 35  years ago but I have hundreds of customers that will testify that they are a good investment and have reduced their electric bill, especially in the summer. (They weren't available then.  Especially if there is a moisture problem with a crawl space, this is a good application.  However, the source of the moisture should be addressed and eliminated if possible due to health concerns)  We put thermostats on the solar attic fans to cut on at 80 degrees and cut off at 70 to save heat in the winter.   You be the judge. 

                                  I agree that radiant barrier is a good investment as well, keep the heat out in the first place and keeps your heat in. 

                                   

                                   

                                  Solar hot water can interface with existing water heaters by adding a preheat tank that captures the hot solution from the roof panels (located in the sun) and preheats the cold water going into your existing water heater.  It is better to add a new tank as well but that is not necessary.  (I concur.  I especially like passive solar water heating systems that include the storage tank.  No freeze concerns as long as the solar collector has a drain down provision.  They do present some structural concerns and may require some additional support.  I do not, however, recommend mounting any type of solar system on a composition shingle roof, because of the roof will have to be replaced long before the solar system and removing and reinstalling a solar system is too costly for most folks.  This is the main reason why you don't see any solar systems from the 70's & 80's still on rooftops in Houston , as there were tens of thousands, if not more, installed.)

                                   

                                  We have units in stock if you are interested contact me offline they are easy to install yourself if needed.  Houston is an ideal market for this as it is hot 8 months out of the year.  (Did you purchase David Sawchak's stock?)

                                   

                                  regards

                                   

                                   

                                  John Miggins
                                  Harvest Solar & Wind Power
                                  "renewable solutions to everyday needs"
                                  www.harvest-energy.com
                                  Phone/Fax 918-743-2299
                                  Cell: 918-521-6223

                                  ----- Original Message -----

                                  Sent: Sunday, December 12, 2004 1:06 PM

                                  Subject: Re: [hreg] Solar Attic Fans OPPS

                                   

                                  Opps.    Please see my correction/comments below in GREEN to my original email.

                                   

                                  LaVerne

                                  ----- Original Message -----

                                  Sent: Sunday, December 12, 2004 12:29 PM

                                  Subject: Re: [hreg] Solar Attic Fans

                                   

                                  Mike:

                                   

                                  Back in the 70's, a study was done in Houston by HUD (I think) regarding attic fans versus other types of attic ventilation and the results came back showing the energy saved (in air conditioned homes) by attic ventilation fans for removing heat didn't offset the amount of energy they used.  So this study showed there was no advantage to powered attic ventilation.  This would also apply to PV powered attic ventilation fans.  It clearly showed that when it came to ventilating attics in Houston , continuous ridge and soffit ventilation performed best.

                                   

                                  (Assuming you are using gas for heating** and that your furnace is located in the attic where it needs combustion air supply from outside), continuous ridge vents balanced with soffit ventilation proportionally located around the entire perimeter of your house is your best option.  If you have hip roofs, you will have to run the ridge vents down the hips.  I would use Cor-A-Vent for the ridge and hip vents, following details you can get from their website.  The soffits vents can be any kind (even galvanized  hardware cloth).  They must can be sized to balance the air admittance into the attic so that the free inflow air flow area is equal to or greater than the free exit area of the ridge vent area.  In other words, don't put twice as much soffit venting on the west side versus the east side of your roof.  It has to be evenly balanced around the house.  Otherwise, you can get water intrusion into your attic during blowing rains, not matter whose ridge vent system is used. 

                                   

                                  Also, be sure to include insulation baffles in your plans so that the air path from the soffit vents to the ridge vents isn't blocked by insulation.

                                   

                                  If your house is all electric, you may want to consider insulating at the roof and eliminating attic ventilation all together, as a lot of moisture is added to the interior of your house from having ventilated attics.  In this area of the country, approx. half of your air-conditioning bill comes from just removing the moisture for the air.  While all this moisture obviously doesn't just come through your ceilings, sheet rock and insulation are not going to stop attic moisture from diffusing down into the interior space.  So eliminating the moisture from this source will not only help reduce your energy bill, but can also provide a healthier indoor environment.  Since dust mites and molds thrive in high humidity environments, eliminating as many possible sources for humidity intrusion into the interior of our homes is prudent.  However, insulating at the underside of the roof will cost more initially.  

                                   

                                  Should you follow the ventilated attic path, if you haven't already stapled a radiant barrier to the underside of your rafters or considered some other means for adding a radiant barrier to the underside of your roof, it should be considered a major component in your strategy to improve your home's performance.  If you decide to insulate with spray-in foam insulation on the underside of the roof deck, then disregard the use of the radiant barrier.

                                   

                                  Hope this helps. 

                                   

                                  LaVerne A. Williams, AIA, LEED AP
                                  architect & building ecologist
                                  LaVerne@...
                                  ENVIRONMENT ASSOCIATES, Architects & Consultants
                                  5828 Langfield Road
                                  Houston , TX 77092-1429
                                  713.528.0000
                                  866.815.2527 toll free
                                  www.environmentassoc.com
                                  30 Years of Leadership in Healthy, High Performance Homes / Green Architecture
                                  Design Counseling / Consulting / Architectural Design / Construction Documents / Construction Administration Services

                                   

                                  **If the water heater is gas, make sure you don't eliminate it's outside air supply for combustion in your insulation /attic sealing efforts.

                                   

                                   

                                   

                                  ----- Original Message -----

                                  Sent: Saturday, December 11, 2004 7:20 PM

                                  Subject: [hreg] Solar Attic Fans

                                   

                                  Hello,

                                   

                                  I guess I have to start somewhere..So I will start with attic fans.

                                   

                                  I live up near Cut-n-Shoot in the woods and I don’t get enough wind to see the old style turbines spin on my roof. I have added more sofit vents and still doesn’t seem to get them moving. So instead of replacing the turbins with new ones, Im looking into changing them out with 2 solar powered attic fans to help cool down the attic. I’m trying to find small PV projects to start with and work up to the bigger ones later after I get the house better insulated.

                                   

                                  Right now this 2 story house is 2200 sq feet with the highest electric bill was at $134.00 this summer. I have been graphing my daily power usage and the highest was 82 KWh for one day. All the bulbs have been replaced with the Compact FL bulbs (60w version).  The attic has to have more insulation added. I was able to get insulation in 30% of the attic this summer. All the A/C ducts are in the way…will finish up this winter. The windows in this house are a step above the aluminum frame. They have double panes but are worthless….they will have to be updated soon. The good thing about this house is that the previous owner paid the money to have the interior walls insulated as well as the exterior but for some reason did a half rear job in the attic. The 30% I put in up there was to cover the corner that didn’t have any. After updating some appliances (washer/dryer, fridge and dish washer) I should be able to move up to the bigger projects.

                                   

                                  Some questions I have are:

                                   

                                  1. At what point (daily KWh usage) is a good point to start adding PV systems. Im thinking in terms of a hobby because off the A/C systems in Houston … you can’t really go off grid or can you? How does it work with the A/C power usage?
                                  2. Where can I get some quality attic fans? What CFM is a good flow to have here in Houston ?
                                  3. Any Ideas on how to hook up a solar water heater that has the water heater situated on the first floor in the middle of the house? Can I use a plain insulated tank in the attic or do I need to tie into another water heater?
                                  4. Anything else I’m missing?

                                   

                                  Thanks in advance for your time!!!

                                   

                                  Mike Schmitt

                                   

                                   

                                   

                                   

                                   

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