Wow, great idea, and the manufacturer actually explains it for DIY-ers! It doesn't really heat a whole house, but for a small hut, it could work on cold spring/fall evenings when you don't want to start the wood stove. You could use it in a small room.
Ive seen people use old doors as headboards before and I always really liked the look. I decided to try it with a french door because it was free and it happened to be exactly the size of a king size bed.