Going on the bizarre theory that houses are easier to cool if the heat is kept out of them to begin with, I finally got around to installing a radiant barrier on our garage door. I got the idea last year when looking at solutions for our attic heat. A lot of university cooperative sites were steering people away from powered cooling (gable fans, for instance) in favor of passive solutions, like radiant barriers. Radiant barriers reflect heat back into space, before it can seep into the conditioned part of your house. I’d like to do the whole attic, but a test was needed first. The garage door is a good candidate for a radiant barrier, as it faces due west and gets cooked by the afternoon sun.

Applying the barrier wasn’t hard at all. It’s essentially bubble wrap covered by aluminum foil. All I had to do was cut it to fit the panels of my door. The barrier fit so snugly into the door panels that they didn’t even need to be fastened.

The results were immediately obvious. As I insulated panel after panel, I could feel the source of heat – the hot door – disappearing. An hour later, I had 95% of the door covered in foil. The windows are the only remaining problem, the sun’s rays still burn right through them.

Radiant barriers aren’t cheap. The 2′ x 25′ roll I used for the door cost around $23. Still, but the radiant barrier seems like a good candidate for the attic, especially considering our air conditioner can’t keep our house cool on hot summer days. If a barrier can cut the attic temperature from 140 degrees to 100, it will make a world of difference in our summertime comfort.