[pianotech] Protection from underfloor heating

[Encore Pianos]

Is that forth, as in forthright; or in moving forth, or have you developed a
lisp?  :-)

The data logger would be interesting.  

I live in New Hampshire, but I suspect that your winter humidity conditions
may be more like ours than different.  It is very common for just about
everybody's house to be too dry, unless they have supplemental
humidification, no matter what kind of heat is used.  Forced hot air can
make the room air extremely dry, RH in January can easily hit 20% in a cold
snap, and rarely hit 30% for a good bit of the winter.  It's also a yo yo
heat, up and down, up and down; particularly if the house is not well
insulated.  My experience with the floor heat is that it is fairly constant,
you have a relatively large thermal mass distributing the heat over a very
large surface area.  The room temperature changes relatively little, and
it's far easier to keep that thermal mass of the floor within a narrow
temperature range than it is to keep bringing it up larger amounts.  While I
have not measured the temperature of the floor, it is not hot to the touch
of even bare feet.  It heats the air sufficiently not by raising its
temperature a large amount, but by simply by raising it constantly over a
large area.  

I don't question that heated flooring can be drying for the reasons stated
by you and others, I am not convinced that it is more drying to a piano than
forced hot air or other heating methods.  I would think that it would raise
the temperature of the piano by almost immeasurable amounts, to say that it
bakes the piano overstates it.  The hotter air at the floor is of course
rising at a constant but very slow rate.  The change in temperature
differential is small, that would seem to limit the change in RH of that air
at the floor to small increments.    Forced hot air runs off a blower and
can really blast the air into the room, air that is quite a bit warmer at
its source.  I think it would be interesting to set an accurate hygrometer
inside a forced hot air duct and measure RH before the air exits into the
room, and also have another hygrometer in the room to compare those
measurements to.  

It's probably been done within the heating industry, but not by any of us.
It would be interesting to have an apples to apples comparison (as much as
possible) between hot air and a radiant floor to see what the measured
differences in RH would be within a given space, all else being equal.  

Will 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Ron Nossaman
Sent: Tuesday, December 11, 2012 8:49 AM
To: pianotech at ptg.org
Subject: Re: [pianotech] Protection from underfloor heating

On 12/11/2012 7:17 AM, Encore Pianos wrote:
> 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).

A data logger with four or five sensors would be interesting, as well as an
indication of when the heat cycle begins and ends to see the lag time
inherent in the system. Setting a heat anticipator on these systems must be
interesting.

Our house was built in 1950 by an architect just out of school. Cinder block
on slab floor ranch, with a poured concrete roof. This is where he learned
what not to do. There is a small fortune in 1/2" copper pipe in the floor
that was originally heated with a boiler in the utility room and regulated
by nests of valves in two cabinets in different parts of the house, the
bedrooms separate from the living areas. It wasn't long after they got
really sick of continually diddling valves that the concrete ate the copper
enough for the leak to inherit the earth, and forced air was retrofitted.
This summer, we installed what I think is the forth forced air system.

Ron N