The most contentious issue I’ve written about since I started blogging isn’t bad Manual Js. Nor is it endorsing government intervention by raising efficiency standards or improving energy codes. Incredibly, it’s not even whether or not naked people need building science. Nope. The topic that really gets readers hyperventilating is powered attic ventilators (PAVs).
Some people swear it’s the best way to keep their attic cool and reduce air conditioning costs. Apparently they haven’t seen the research about what works better than PAVs without the drawbacks.
Do you really need to cool your attic?
First off, let’s limit the discussion in this section to homes with unconditioned attics. Conditioned attics are great, but I want to focus on all the homes out there that have the insulation and air barrier at the ceiling, not the roofline.
What about new homes? If you’re designing and building a new home, keeping an unconditioned attic cooler (in summer) is pretty much irrelevant. Just make sure the ceiling is airtight and fully insulated, and the temperature in the attic doesn’t matter much. Whether it’s 110°F or 130°F, there’s not much difference in the amount of heat flowing from the attic to the living space below.
Oh, you also have to make sure not to do something stupid, like putting your air handler and ducts up in the attic. When you’re designing and building a new home, these are choices you can and should make. If you don’t, worrying about how best to keep the attic cool is a band-aid on a self-inflicted wound.
In existing homes, the question is important. (Again, I’m assuming that you’re not considering a…