I'm trying to do a rough calculation to find the "operating temperature" of a concrete floor. I've found a paper that discusses calculations for rate of heat loss from the slab to the earth: here. (It's a Word file - don't freak out.) Which gave me a fairly reasonable figure of ~2400Btu/hr (~700W) for heat loss. Also, I've got the equation for convective heat transfer as: q = hc*A*dT. here However, I'm not sure I can just assume that the heat loss to the earth will be exactly balanced by the heat transfer from the air. Or maybe I can, since the linked paper seems to give the heat loss figures for an equilibrium situation between the slab & the air? If I do that, and take 10.45 as the convective transfer coefficient (hc), A ~= 1000sf (~93m2), I get something < 1 degree for dT. That doesn't seem right. Basically, I'm trying to predict the temperature of the floor, given adequate heating of the interior space by forced air. (With no air stratification, due to a gigantic fan.) It doesn't seem intuitive that a bare concrete floor of something like 8" thick would be almost exactly the same temperature as the air. Have I missed something? EDIT: it occurs to me that the convection equation above may not apply anyway, since the action in this case it reversed... rather than floor heating air, hot air rising - it's air heats floor, cold air stays where it is, unless moved by some external force. But I'm told that this giant fan (8' diameter!) can reduce stratification to 1deg from ceiling to floor.