I should explain that in Atlanta, when they install a heat pump, they include a small, auxiliary, el-cheapo gas fired furnace along with it. It seldom turns on. I don't know about Florida and other warm places.
In rural Japan where the walls are made of paper, they used to heat with kerosene stoves. That is very dangerous, bad for your health, and just plain crazy. It almost killed the child of a friend of mine years ago. I hope these are seldom used today.
