Japan also had a history of homes with permanent passive air circulation; old Japanese buildings are often not much better than sleeping outside. That plus sitt

Japan also had a history of homes with permanent passive air circulation; old Japanese buildings are often not much better than sleeping outside. That plus sitting-on-the-floor lends itself to a kotatsu culture. But different cultures work differently, and as a result the same solutions don't fit other places. There are probably a bunch of different solutions that we just need to make it a little easier for local people (& contractors) to try out.