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Re: [hreg] Solar Attic Fans

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  • Environment Associates Architects
    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
    Message 1 of 13 , Dec 12, 2004
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      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 used 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.
       
      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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    • Roxanne Boyer
      I added an electric fan with a thermal switch in the attic of a house I had and it made an incredible difference. The house had screen vents in the corners of
      Message 2 of 13 , Dec 12, 2004
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        I added an electric fan with a thermal switch in the attic of a house I had and it made an incredible difference.  The house had screen vents in the corners of (not sofit & ridgevents) the east and south side; by putting the fan blowing out on the west side there was a marked improvement - the attic was bearable in the summer.  If I had to do it over, I would put a solar powered fan on that house.  Mike, since you have the sofit & ridge vent system, that may be a different situation.
         
        I am also thinking of adding PV as a hobby.  I plan on using PV electricity from solar panels and make up additional power as needed from the grid.  I may start with a 1 or 0.5 kW system and build from there. 
         
        My hot water is in the middle of the first floor of my 2 story house as well.  I looked into how to install a solar hot water heater.  There is a vertical shaft running up the middle of the house which supplies air from the attic to the gas heater; I could put all the piping there without having to make any structural modification or cutting into any walls.  Maybe you could do the same.
         
        Regards,
        Chris
         
        ----- 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

         

         

         

      • Gary Beck
        I would work this project on the basis of biggest benefit for lowest cost. Make a list and then start with finding all the air leaks and close them by what
        Message 3 of 13 , Dec 13, 2004
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          I would work this project on the basis of biggest benefit for lowest cost.

           

          Make a list and then start with finding all the air leaks and close them by what ever means. Talk and Caulk is cheap. Then make sure you have adequate (open & uncovered) soffit and ridge or gable end vents.  If you have double pane windows these are far from worthless. Single pane leaking steel casements are worthless. Replacing my casements with vinyl double glass low E made a huge difference, but you will not see much improvement over what you already have. Just make sure that they all close properly and every opening (windows and doors) has good functional weather stripping and are neatly caulk at the frames. At $134 month in the summer your AC unit sounds okay.  But if your AC is more than 8 or 10 years old and you plan on staying in the house consider replacing it with the highest SEER that you can find - BUT be sure that the AC company does not sell you an oversized system.  Shorts runs by an oversized system quickly lowers the effective SEER.  A new unit can make a huge difference on operating cost (you sound okay though) and comfort. My payout was in less than 3 years over an old Carrier unit. As last resort consider adding more insulation the attic by blowing in cellulose. Rent an insulation blower from Home Depot making this go fast and you can easily make an extension wand that let you get back into tight spaces.

           

          My only experience with a solar powered fan is on sailboats - a $150 solar vent does not move much CFM of air at all.  On a house, even the several units like this you will need would have no effect before and especially AFTER you have done all the other inexpensive above items. But then I have never seen a bigger home version - which could have a much big PV so a bigger motor pulling more CFMs - but I assume this will also cost much more. I would do all the other stuff and then spend money on a solar powered water fountain next to a solar reflective BBQ.

           

          -----Original Message-----
          From: Mike Schmitt [mailto:1954lincoln@...]
          Sent: Saturday, December 11, 2004 7:21 PM
          To: hreg@yahoogroups.com
          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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        • Paul Archer
          ... This is something I need to do at my house. I can t afford to do the whole house, but we ve got two south-facing windows that are about 4 x7 each, and the
          Message 4 of 13 , Dec 13, 2004
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            1:18pm, Gary Beck wrote:

            > I would work this project on the basis of biggest benefit for lowest cost.
            >
            >
            >
            > If you have double
            > pane windows these are far from worthless. Single pane leaking steel
            > casements are worthless. Replacing my casements with vinyl double glass low
            > E made a huge difference, but you will not see much improvement over what
            > you already have. Just make sure that they all close properly and every
            > opening (windows and doors) has good functional weather stripping and are
            > neatly caulk at the frames.

            This is something I need to do at my house. I can't afford to do the whole
            house, but we've got two south-facing windows that are about 4'x7' each, and
            the rooms those windows are in are the hottest in the house by a huge
            margin.
            Can anyone recommend any brands/models/businesses for replacement windows
            where there's a good balance between efficient and inexpensive?

            Thanks,

            Paul
          • David Power
            Paul, I d take a look at Showcase Enviroshield windows. They are made in Houston, I put them on my house and have been very pleased so far. They use a low-E
            Message 5 of 13 , Dec 13, 2004
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              Paul,
               I'd take a look at Showcase Enviroshield windows. They are made in Houston, I put them on my house and have been very pleased so far. They use a low-E that's designed for our latitude U-value of .30 and an R value of 3.33 , light transmission of 78% and a solar heat gain of .33 . Sealed welded vinyl construction .
               
               
              David

              This is something I need to do at my house. I can't afford to do the whole
              house, but we've got two south-facing windows that are about 4'x7' each, and
              the rooms those windows are in are the hottest in the house by a huge
              margin.
              Can anyone recommend any brands/models/businesses for replacement windows
              where there's a good balance between efficient and inexpensive?

              Thanks,

              Paul

            • Mike Schmitt
              The double pane widows I have are the Aluminum frames and have the condensation in the middle. At my old house we replace 2 windows plus one standard size. The
              Message 6 of 13 , Dec 13, 2004
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                The double pane widows I have are the Aluminum frames and have the
                condensation in the middle.

                At my old house we replace 2 windows plus one standard size. The 2 large
                windows were 4x9 they were the largest that they could make of the vinyl
                type. You could tell a difference after they were in... a lot cooler. they
                had foam filled vinyl. They were expensive 1200 a piece installed (Window
                Guys) would I use them again? **probably not**. We tried to order some more
                windows and the different sales guy tried to stick it to me. I watched the
                installer put them in..its not hard at all. On this house im going install
                them myself. I think I can get the same quality by ordering them through
                Home depot or Lowes. But I can say from experience that the new windows made
                a heck of a difference..I will definitely change out the windows here.


                One thing that has stuck with me for a while...I was watching a show on
                older architecture and they talk about how the older designs with the big
                porches worked well because they blocked the sunlight BEFORE it made it into
                the house. I was thinking about maybe using some awnings or other structures
                to block the sun from hitting the west side of the house. The majority of
                the house has windows on the west side and these windows are located on the
                sunny side and not the shaded side of the west end. I know for a fact how
                much heat builds up here when I spent the summer staining the house..I got
                fried pretty well.


                Mike






                -----Original Message-----
                From: Paul Archer [mailto:tigger@...]
                Sent: Monday, December 13, 2004 1:35 PM
                To: hreg@yahoogroups.com
                Subject: RE: [hreg] Solar Attic Fans


                1:18pm, Gary Beck wrote:

                > I would work this project on the basis of biggest benefit for lowest cost.
                >
                >
                >
                > If you have double
                > pane windows these are far from worthless. Single pane leaking steel
                > casements are worthless. Replacing my casements with vinyl double glass
                low
                > E made a huge difference, but you will not see much improvement over what
                > you already have. Just make sure that they all close properly and every
                > opening (windows and doors) has good functional weather stripping and are
                > neatly caulk at the frames.

                This is something I need to do at my house. I can't afford to do the whole
                house, but we've got two south-facing windows that are about 4'x7' each, and
                the rooms those windows are in are the hottest in the house by a huge
                margin.
                Can anyone recommend any brands/models/businesses for replacement windows
                where there's a good balance between efficient and inexpensive?

                Thanks,

                Paul




                Yahoo! Groups Links








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              • J. P. Malone
                Is radiant barrier paint (see link below) more cost-effective than other radiant barriers or solar attic fans. HYPERLINK
                Message 7 of 13 , Dec 14, 2004
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                  Is radiant barrier paint (see link below) more cost-effective than other radiant barriers or solar attic fans.

                   

                   

                   

                  http://www.hytechsales.com/prod85.html

                   

                   

                   

                  J. Patrick Malone

                   


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                • Gary Beck
                  It sounds like snake oil but I have an experienced remodeling contractor / brother who has applied it and swears by it. ... From: J. P. Malone
                  Message 8 of 13 , Dec 14, 2004
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                    It sounds like snake oil but I have an experienced remodeling contractor / brother who has applied it and swears by it.

                     

                     

                    -----Original Message-----
                    From: J. P. Malone [mailto:JPMALONE@...]
                    Sent: Tuesday, December 14, 2004 12:07 PM
                    To: hreg@yahoogroups.com
                    Subject: [hreg] Solar Attic Fans

                     

                    Is radiant barrier paint (see link below) more cost-effective than other radiant barriers or solar attic fans.

                     

                     

                     

                    http://www.hytechsales.com/prod85.html

                     

                     

                     

                    J. Patrick Malone

                     




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                  • Roy Holder
                    the Paint works fine (practical experiance with it), but as far as more cost-effective than other radiant barriers , that could be debated forever. In a
                    Message 9 of 13 , Dec 15, 2004
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                      the Paint works fine (practical experiance with it), but as far as 'more
                      cost-effective than other radiant barriers', that could be debated forever.

                      In a remodel situation, maby, in new construction, maby not, depends mostly
                      on installation labor.

                      At 02:54 PM 12/14/2004 -0600, you wrote:
                      > It sounds like snake oil but I have an experienced remodeling
                      >contractor / brother who has applied it and swears by it.
                      >-----Original Message-----
                      > From: J. P. Malone [mailto:JPMALONE@...]
                      > Sent: Tuesday, December 14, 2004 12:07 PM
                      > To: hreg@yahoogroups.com
                      > Subject: [hreg] Solar Attic Fans Is radiant barrier paint (see link
                      >below) more cost-effective than other radiant barriers or solar attic fans.
                      > http://www.hytechsales.com/prod85.html J. Patrick
                      >Malone
                      >
                      >
                      > Yahoo! Groups Sponsor ADVERTISEMENT
                      >
                      > Yahoo! Groups Links
                      > To visit your group on the web, go to:
                      >http://groups.yahoo.com/group/hreg/
                      > To unsubscribe from this group, send an email to:
                      >hreg-unsubscribe@yahoogroups.com
                      > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
                      >
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                    • Mike Schmitt
                      Gary, What kind of sprayer did they use to to get the paint p into the corners. Mike _____ From: Gary Beck [mailto:eco@eco-holdings.com] Sent: Tuesday,
                      Message 10 of 13 , Dec 15, 2004
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                          Gary ,

                         

                        What kind of sprayer did they use to to get the paint p into the corners.

                         

                        Mike

                         

                         

                         


                        From: Gary Beck [mailto:eco@...]
                        Sent: Tuesday, December 14, 2004 2:55 PM
                        To: hreg@yahoogroups.com
                        Subject: RE: [hreg] Solar Attic Fans

                         

                        It sounds like snake oil but I have an experienced remodeling contractor / brother who has applied it and swears by it.

                         

                         

                        -----Original Message-----
                        From: J. P. Malone [mailto:JPMALONE@...]
                        Sent: Tuesday, December 14, 2004 12:07 PM
                        To: hreg@yahoogroups.com
                        Subject: [hreg] Solar Attic Fans

                         

                        Is radiant barrier paint (see link below) more cost-effective than other radiant barriers or solar attic fans.

                         

                         

                         

                        http://www.hytechsales.com/prod85.html

                         

                         

                         

                        J. Patrick Malone

                         

                         




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                      • Mike Correale
                        You can buy the E-Barrier paint at Sherwin Williams for about $41.99 a gallon which covers aprox. 200 square feet (it comes in a 5 Gal bucket).  If you have a
                        Message 11 of 13 , Dec 16, 2004
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                          You can buy the E-Barrier paint at Sherwin Williams for about $41.99 a gallon which covers aprox. 200 square feet (it comes in a 5 Gal bucket).  If you have a friend that is has an account at Sherwin Williams - have them buy it for you and save some money.  It works petty well, BUT it must be applied when the attic temp is below 80 degrees so the window for application is short.
                           
                          When it comes to Active ventilation systems, the solar power ventilators come one of two configurations - attached panel ($340+) or the detached panel ($299+).  Both work well, are very quite, reliable and can save $8-$11 a month in operating cost (depending on time of year and electric cost), over the standard 300 watt electric unit.  So their payback in really not that long.  One thing that most folks overlook is that for proper venting, there needs to be more input than output.  for example most solar fans are rated at 850CFM that means for each fan the input must be aprox. 1200 CFM (enough openings at the lowest part of the roof line to allow air flow).
                           
                          Mike
                           
                           

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                        • Mike Schmitt
                          Thanks everyone for taking the time to email the info. I have learned a lot about the attic fans and other knowledgeable things about the attic space. I will
                          Message 12 of 13 , Dec 21, 2004
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                            Thanks everyone for taking the time to email the info. I have learned a lot about the attic fans and other knowledgeable things about the attic space. I will try to record as much data as I can to have something to give back to the group.

                             

                             Again thanks…there will be more questions to follow soon

                             

                             

                             

                             

                             


                            From: Mike Correale [mailto:correale@...]
                            Sent: Thursday, December 16, 2004 2:11 PM
                            To: hreg@yahoogroups.com
                            Subject: RE: [hreg] Solar Attic Fans

                             

                            You can buy the E-Barrier paint at Sherwin Williams for about $41.99 a gallon which covers aprox. 200 square feet (it comes in a 5 Gal bucket).  If you have a friend that is has an account at Sherwin Williams - have them buy it for you and save some money.  It works petty well, BUT it must be applied when the attic temp is below 80 degrees so the window for application is short.

                             

                            When it comes to Active ventilation systems, the solar power ventilators come one of two configurations - attached panel ($340+) or the detached panel ($299+).  Both work well, are very quite, reliable and can save $8-$11 a month in operating cost (depending on time of year and electric cost), over the standard 300 watt electric unit.  So their payback in really not that long.  One thing that most folks overlook is that for proper venting, there needs to be more input than output.  for example most solar fans are rated at 850CFM that means for each fan the input must be aprox. 1200 CFM (enough openings at the lowest part of the roof line to allow air flow).

                             

                            Mike

                             

                             




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