"It depends on the country and areas within it" Well, obviously it does, but I would think most houses in europe do have to be heated and were build in the las

"It depends on the country and areas within it" Well, obviously it does, but I would think most houses in europe do have to be heated and were build in the last 60-70 years and those I was refering to. And before that, yes it was something like 2 bugs cancel each other out. Leaky windows prevents mold. (And in general only rich people could afford to heat the whole house)