[cd34]

I think the theory is that a heated floor will radiate heat and the room will be kept warm rather evenly since heat rises. The flooring subsurface is much better at retaining heat than air is -- especially when the air isn't humidified. I can see where having a heated floor would be nice in the northern latitudes.

There is a building in China or Japan where the building's air temperature is maintained at 60F in the winter, and each office has individual ceramic heaters. They found it more efficient to heat a small area with a tiny heater than to heat an entire floor.

If you light a match and hold it in your room, the room doesn't warm up, but, if you hold it under your finger, you feel the heat rather quickly.