[pianotech] Protection from underfloor heating

[Ron Nossaman]

On 12/11/2012 11:15 PM, Susan Kline wrote:

> It's been awhile since I studied this, but I do know that sitting in a room
> with hot soapstone panels radiating into it is more satisfying than
> heating the air and
> sending it through floor vents.

Yes it is, as is an open fire. We evolved under a sun providing a 
wonderful radiant heat source that will always feel right to us, but 
that's beyond and outside the subject. The point I've been trying to 
make is that so called radiant floor heating doesn't get the floor hot 
enough to radiate heat to any significant degree. Certainly not enough 
to accurately call it radiant floor heating. The warm floor warms the 
air in contact with it and that air rises into the room by convection. 
It's like one of the old what they used to call gravity furnaces, which 
is really a convection heater, only with the floor heat, the entire room 
is the plenum and the temperature of the delivered air is much lower.

My comment about thermals in the desert was intended to point out the, I 
thought, unavoidably obvious similarities in that the warm ground heated 
the air, which then rose as thermals by convection. The fact that the 
desert floor is heated radiantly by the sun and the floor is heated 
electrically, by hot water, or by fire channeled underneath like the old 
Roman baths is immaterial. At the low temperatures used to heat floors, 
there is very little radiant heat involved and it's not radiance that 
heats the air in any of these cases. It's conduction.

Ron N