This was actually somewhat of a weak point in the story: Chinese people do not leave the heater off out of frugality but because they think it's unhealthy to ha

This was actually somewhat of a weak point in the story: Chinese people do not leave the heater off out of frugality but because they think it's unhealthy to have a large temperature difference between the outside of a container (a house, say, or your own body) and the inside. Of course modern, wealthy Chinese are starting to eat ice cream in summer and turning on the heat in winter (and, to be fair, in places where it gets really, really cold, like in Beijing, they've always had heating in winter) so this attitude is changing, but some of it still persists. Bottled water (and beer in restaurants!) is mostly sold unrefrigerated and Chinese shopping malls in summer are nowhere near as glacial as their counterparts in SE Asia or the west.