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Re: [hreg] Solar Attic Fans OPPS

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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 1 of 17 , Dec 13, 2004
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      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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    • 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 2 of 17 , Dec 13, 2004
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        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 3 of 17 , Dec 13, 2004
        • 0 Attachment
          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.
          Checked by AVG anti-virus system (http://www.grisoft.com).
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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 4 of 17 , Dec 13, 2004
          • 0 Attachment

            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 5 of 17 , Dec 13, 2004
            • 0 Attachment
              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 6 of 17 , Dec 13, 2004
              • 0 Attachment
                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 7 of 17 , Dec 13, 2004
                • 0 Attachment
                  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 8 of 17 , Dec 13, 2004
                  • 0 Attachment
                    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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                    Checked by AVG anti-virus system (http://www.grisoft.com).
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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 9 of 17 , Dec 13, 2004
                    • 0 Attachment
                      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 10 of 17 , Dec 14, 2004
                      • 0 Attachment

                        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 11 of 17 , Dec 15, 2004
                        • 0 Attachment

                          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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                          Checked by AVG anti-virus system (http://www.grisoft.com).
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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 12 of 17 , Dec 15, 2004
                          • 0 Attachment

                             

                            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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