Meet the Ondol, a traditional Korean system for heating one's house
By placing the fire and chimney on opposite sides of the house and constructing a tunnel between them, heat is pulled through the tunnel, heating the floors and helping distribute heat more evenly.
as far as i'm aware (not korean, never been there, just an internet weirdo) ondol heating of a sort is still used for the floors in korea. i assume it's more of a radiator system now though?
Modern ondol systems use piped hot water. One of the pleasures of being in Korea in winter is finding a literal hot spot to sit or lie on, since the heating is not perfectly even.