> It would be so easy to make every building comfortable.
Every time there's a thread on air conditioning, we get smug comments like this, usually from places where the climate is so comfortable to begin with that air conditioners are the least necessary. Okay, Los Angeles needs them two or three months a year. Anyone from San Francisco, on the other hand, forfeits the right to talk about air conditioners in my opinion.
I'm sitting in a major metropolitan area in Asia. The temperature right now is 39'C (102'F), and can easily go over 45'C (113'F) in the sun. The humidity fluctuates between 50% at midday and 90% at night, and the temperature remains above 30'C (86'C) through most of the night, too. I would love it if you could make every building comfortable under these constraints. Hint: increased ventilation only brings in more heat. Any cooling solution that relies on evaporating H2O does not work, either, so don't bother bringing those Kickstarter gadgets here. Most of the old world is in the same boat. Coastal California is the exception, not the norm.