Replies

1. 
   sungod | Sep 29, 2003 07:07pm | #1

   Attics with a lots of insulation cause the interior of the house to be HOTTER in summertime.  During the day, the house is relatively cool, but come around the evening, after the sun goes down the inside of the house is HOTTER than the outside.  My theory is that insulation does not stop the movement of hot to cold.  Insulation just slows the travel and depending on the material, insulation also holds or retains the heat.  Go in an insulated attic after the sun goes down and see how hot it is.  If the evenings are cool and the outside air is clean and there is no A/C then go one step further with a whole house fan

2. 
   parrothead | Sep 29, 2003 07:08pm | #2

   Hi John, I have one in my house (southern Indiana), blown in insulation, soffit and eave vents, and don't have any problems. It actually does not get much use, the humidity here picks up very early in the year and it just doesn't do that good of a job when its humid.

   After a couple of years it does not close and seal like it use to, so I have to cover it every winter with plastic to keep the drafts out. I use the shrink plastic like you use for windows with the double stick tape.

   We are the people our parents warned us about. J. Buffett
3. 
   Bigslice | Sep 29, 2003 08:15pm | #3

   I have installed one of these fans in the gable of a bungalow and it made a significant difference. It shouldn't affect the blown in insulation in any way. I also ensured a separate shut-off switch near the attic door so that I could manually turn it off in the winter.

   Even with the a/c on the house used to get pretty warm at the end of the day, when the sun set against our west-facing kitchen, which has floor to ceiling glass on the walkout to the deck. Since I installed the gable fan it really draws a lot of the heat from the attic and I find that it works most in the late afternoon & evening.

   Keep in mind that I live in a bungalow, so I feel the difference on the main level. I'm not so sure it would make a major impact to the main level of a 2 storey home. The fact that the house has ridge and soffit venting is already a step ahead of the game.

4. 
   csnow | Sep 29, 2003 10:02pm | #4

   Hard to imagine you would get much heat radiating back from attic with all that insulation.

   How about a whole house fan.

   Cools the whole house AND blows the heat out of the attic.

   I have one of these from Tamarack Technologies.

   Probably need air conditioning half as often.

   Automatic foam doors seal tight.  Low power consumption. Easy install.  I'm very happy with it.

   http://www.tamtech.com/hv1000.htm

5. 
   rjw | Sep 29, 2003 10:03pm | #5

   A concern with attic fans is that they might concentrate air movement in one area, and leave other areas without significant ventilation with resulting condensation and possible mildew/mold growth.

   I think good natural ventilation (soffits and ridge or lotsa off ridge) is better, but I can't say I've seen a lot of houses with attic fans and "dead spots."

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