[pianotech] Protection from underfloor heating

[Jim Ialeggio]

The issue any heat source presents to furniture, sinuses, skin and 
pianos is the RH of the house.  The heat source is not the cause of the 
problem.

The problem attributed to infloor radiant heat is one of air changes in 
the house. The draftier the house, the more outside air is brought in an 
warmed up. As the cold exterior air enters the house, it warms. As it  
warms the RH of that exterior air plummets, pulling moisture out of the 
interior house air. As the interior air RH drops moisture is pulled out 
of the home's hygroscopic objects, including sinuses which are 
hygroscopic objects.   It's the outside air that sucks the moisture out 
of hygroscopic objects, not the heat. The more air changes, the lower 
the EMC will be.

It also follows that the more the air changes, the more expensive it is 
to run any heat system, and the hotter it must be run

We use this same concept to dry soundboards in our hotboxes...heat the 
space and change the air vigorously...then watch the RH and resultant 
EMC drop.

I always hear these dire scenarios regarding infloor heat, but I have 
been living in a well insulated, infloor radiant building with wide pine 
and wide walnut floors for 25 years. Air changes are controlled, RH in 
the house is in the 40-50% range all winter without humidification. The 
space is comfortable, not overly warm, floor runs cool and 
intermittently. Measured EMC of woods in the home are 7.5-8% in the dead 
of winter. It is economical heat. Wide pine floors exhibit no...read, no 
seasonal or permanent gapping. The wide walnut actually prefers the 
winter, because that's when I laid it. In the winter it is flat, in the 
summer it tends to cup a tad...(walnut is a reactive wood moisture 
wise). However, no compression sets on any of the floors are exhibited.  
Incidently, both my wife and myself never have sinus trouble at home, 
but go visiting in a forced hot air house and we are both dying.

Piano has a full DC and a full floor length permeable cloth cover. I 
have the floor length cover because we like to have all the windows open 
in the summer, and it helps keep the piano's micro-climate intact. Piano 
is stable and happy...

The moral...my take...Control the RH of the space and insure an 
effective micro-climate for your piano. First check and correct the air 
changes in the house, it will improve all kinds of nasty heating system 
effects, as well as help the piano. Look at the house and its heating as 
a whole system, not as a force that wantonly and gratuitously destroys 
unsuspecting pianos.

Jim Ialeggio


-- 
Jim Ialeggio	
jim at grandpianosolutions.com
978 425-9026
Shirley Center, MA