In north China, there are indoor heating radiators which connected to the central heating system. There is at least one coal heating system (maybe a fired power plant) which send boiling water to those radiators or radiant floor heating.

There are also Kang beds or a stove in rural north Chinese houses. But it makes more pollution (even monoxide) from burning coals so now central heating are system are popular.

In some houses without a stove or radiator, people use space heaters or electric blankets. But it always leads to accidental fires. So some people prefer hot watered mats.