On Jan 15, 11:26*am, wrote:
On Thu, 15 Jan 2009 11:02:27 -0500, "badgolferman"

wrote:
Ed Pawlowski wrote:

Heat can radiate down, just as the sun does.

Is there an up and down in space? *The sun is round and radiates in all
different directions because of its shape.

It seems to me that what is often called radiant heat isn't radiation
at all. *The heating elements do radiate to the nearby building
materials (the floor) and then the heat is conducted through the floor
to your feet and shoes as well as nearby air. *The heat is then spread
around the room via convection. *In other words, using the sun's
radiation as an example isn't very helpful to someone wanting to
install radiant heat in their apartment. *

The floor is much better than the ceiling because heating your feet
makes you feel warm at a lower air temp.

yeah, for either the floor or the ceiling to do much radiating, it
would have to be red hot. it's convecting.

friend of mine had a house built with "radiant heating" in the ceiling
decades ago, state of the art whenever it was built. they hated it.
didn't heat well, and it made the ceiling plasterboard or whatever it
was crack a lot. they said there was just that one brief period when
people were installing it, they stopped pretty quick when it turned
out to be a dud.