[pianotech] Protection from underfloor heating

[Dean May]

Radiant heat works not by warming the air, though there is some of that, but
by radiating the heat, duh. ;-) Objects with mass in view of the radiant
heat source absorb the heat and began to warm in temperature. The closer the
object to the source, the more heat is absorbed. A piano with lots of mass
sitting very close to the source will absorb lots of heat. While air, with
negligible mass, will not absorb much heat. So measuring the air's
temperature will not be any kind of indicator as to how much heat the piano
is getting. 

Dean
Dean W May                (812) 235-5272 voice and text 
PianoRebuilders.com    (888) DEAN-MAY        
Terre Haute IN 47802

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Encore Pianos
Sent: Tuesday, December 11, 2012 8:18 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Protection from underfloor heating

Has anyone here ever measured the ambient air temperature directly above a
radiant floor? (say 2 inches as a starting point)  I am very curious as to
what that temperature would measure there, and at intervals above that (say
every foot or so).  

Will Truitt 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Tuesday, December 11, 2012 7:34 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Protection from underfloor heating

On 12/11/2012 2:50 AM, David Boyce wrote:

>
> I was pondering the nature of the problem.  Why is it bad to have heat 
> at the bottom of the piano?  Given that the underfloor heating won't 
> be heating the room itself any hotter than any other heating system, 
> and given that the floor does not get scalding hot, and given that 
> wood is not a good conductor of heat, is it really so bad to have a 
> warm-ish floor?  What does it do to the piano?

It's like a whole house Dampp-Chaser without the humidification. Or like
radiators, with the piano directly above them. Convection keeps the piano
immersed in warm air not only all the time the heat is on, but until the
thermal mass of the floor cools, which will be in the spring when the heat
is turned off. Forced air heat leaves the floor and the first foot of air
above it cold, so you're not heating the piano as much or as constantly and
cooking the moisture out of it. So the overall temperature isn't directly
the problem, I think, it's the resulting MC of the wood in the piano.
Ron N




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