I knew a Czech guy who was not just a builder, but a real renaissance man type. This was the kind of guy that would blacksmith his own hinges for the barn he was building... anyway, he showed me a brick stove he built in his house... it was really sort of a bed or bench sized rectangle that had exhaust snaking all the way through it like a maze. It would heat the whole brick base and warm the rooms for hours on very little wood. He said it was a common old school tech used the world over... just not here I guess!