BERLIN — After moving to Berlin from Honolulu, Wyatt Gordon was surprised when his new German roommate marched into his bedroom at 8 a.m. and threw open the windows.

It turned out that his cohabitant, Laura, maintained a strict ventilation regime. Three times a day, at precise times, all the windows in the apartment needed to be opened. It didn’t matter whether it was the dead of winter or a weekend morning, or if Gordon had company — rules were rules.