I won a house in Tucson, AZ with a crawlspace attic. I had alwaysthought the attic should be vented, so that the heated air from the day's sun would get out fast, and I wouldn't have a pocket of ~150 degree air on the other side of the attic insulation. The insulation is loose fill between the cewiling joists.I just had an energy evaluation from a licensed company, and they recommend replacing and upgrading gthe insulation (which I knew already), but in discussing the venting issue they recommend against it, on thegrounds that their tests should venting or not venting has essentially no efect on cooling costs, when (a) the attic is well insulated, and (b) the living space is very well sealed (so as to prevent air draw into the attic).I should say it will be a LOT easier if I don't need to install additional air flow in the attic -- soffit vents would be difficult to install, and I have read very mixed reviews on e.g., attic fans (fire hazard, noiuse, effectiveness).So: Experience? Advice?ThanksAndy Barss

Insulate first. It sounds like you're already convinced thecurrent insulation needs an upgrade. I'd likely pass on the attic vents since you say that willbe difficult/expensive to address. However, it's somethingyou could re-evaluate later if you feel the need.

Venting Attics for Heat Control, or Not?

Jul 16, 2011 21 Replies

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John Gilmer 15 years ago

Interesting.

I find myself trying to make "engineering sense" out of that.

The best I can come up with is that when the sun starts to go down, the roof will cool (via radiation) a lot faster than will the air.

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LouB 15 years ago

All they were saying is that it may not be cost effective to install venying IF the other two conditions are met. Note: That is a big if.

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