YSK if your power goes out in the winter and your home starts getting cold, go to the bathroom, close the door, plug the bathtub drain, and turn the shower on hot. Once the tub is full (or you run out of hot water) turn the water off. This will heat the room for around an hour.
from /r/YouShouldKnow
YSK如果冬天停电，家里开始变冷，就去浴室，关上门，堵住浴缸排水管，然后把淋浴器开热。一旦浴缸满了（或者你用完了热水）就把水关掉。这将使房间加热一个小时左右。