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Old 11-17-13, 12:31 AM   #17
Exeric
Apprentice EcoRenovator
 
Join Date: Aug 2012
Location: California
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So the obvious answer to what I just said is add more insulation at those heat stress points. That's what I did and I used duct board rather than foam board, mostly because it was my preference, even though it is more expensive. Total cost was about 350 bucks for the duct board but its been worth it. The temperature near the roof but below the radiant barrier does not get over about 3 degrees of the rest of the open uninsulated part of the house. My house is under major construction as later photos will show but the one and only advantage is that it pretty much eliminates heated or conditioned air from the living space (except my bedroom) leaking into areas that I don't want and affecting the temperature results. Its basically one big unconditioned space except right above the radiant barrier at the roof.

It seems to have worked. The dramatic spiral in lower heat rises as we approach the winter solstice has been arrested. I'm getting consistant heat rises at or near 30 degrees above outside ambient. I think that's pretty good for having a foot diameter vent wide open at the top of the roof!



That 60 degree temperature reading is in that large unconditioned space. So you can see that even at mid-afternoon while the outside temperature was 63, bedroom temp around 70ish, and roof temperature was 93 degrees, there is surprisingly little leakage of heat from the roof to the unconditioned space. There is no ceiling drywall in the house yet.
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Last edited by Exeric; 11-17-13 at 12:59 AM..
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