> The hot air flowing from outside through your windows could be compressed making it cool. Compressing air actually makes it hotter, but that's not what's hap

> The hot air flowing from outside through your windows could be compressed making it cool. Compressing air actually makes it hotter, but that's not what's happening. Forcing air through a smaller space makes it flow faster, which ironically makes it less dense -- and hence colder. It's the same effect that people claim holds airplanes up. (But doesn't. That's mostly the angle of attack.)