I've found many houses I've been in to be extremely stuffy and stale inside...I think most American homes fall into a bad middle ground for indoor air quality:

I've found many houses I've been in to be extremely stuffy and stale inside...I think most American homes fall into a bad middle ground for indoor air quality: well enough sealed to trap indoor pollutants, but lacking the more sophisticated HVAC systems that can efficiently exchange fresh air. Additionally, it seems that many Americans also really hate opening their windows (and indeed the climate often doesn't really lend itself to opening the windows, in some places ever). I grew up in a drafty old house with no A/C, and even as a kid felt other people's–newer, not drafty, air conditioned–homes had an airless feeling. It's been interesting to follow the recent studies on indoor CO2 and other air pollution...I don't feel quite so crazy for wanting to open the windows all the time when visiting family.