[spookthesunset]

> A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.

I wouldn't want to live in a house where I couldn't open the windows all the way. Near-perfect energy efficiency is something to strive for but there is something to be said for being able to open the window and get a nice breeze blowing through the house. Even if it isn't the most energy efficient it's okay with me.