[pianotech] Protection from underfloor heating

[Joseph Giandalone]

I think it would be accurate to say that Infrared is a form (spectrum range) of electromagnetic radiation, not of "light" because you can't actually SEE it (it's in frequencies just lower – wavelengths just longer – than human eyes can detect).

This is a great discussion, please keep it up, I may be learning something here.

Now, Why is it that in my longterm observation here in mid-New England, pianos in underfloor-heated homes have the most extreme symptoms of seasonal humidity variation? These homes I'm thinking of are "ranch" homes with no basement, and I have long thought that it might be that these rooms are sitting on concrete slabs that allow moisture to percolate through (that's a technical coffee-making term) in summer, then in Heating Season there's something about this type of heating system that just bakes the air so dry that anywhere that air contacts a source of moisture (its interface with wooden surfaces e.g.) it will accept and accept and accept water vapor (due to the equilibrium pressure or whatever you call it.) So it's not that the piano is warmer than the rest of the room (as might be the case where it's picking up radiant heat from a baseboard system or whatever – or from convection from a forced hot air register) it's that the entire room is godawful dry (and especially compared to what it was in the summertime.)

I have no experience taking instrumental readings of the relative humidity in these places. What are the variables and mechanism that might acount for this godawful dryness? (Asuming, of course, that my aforementioned "longterm observation" has validity.)

Joseph


On Dec 12, 2012, at 12:15 AM, Susan Kline wrote:

> If I have even a glimpse of how this works, infrared is a form of light, and 
> when it shines on a mass, the mass gets warmer. That's why my masonry stove 
> can heat me while the air is still not all that warm. And I think that's why 
> the bakeoven (which is the firebox, but after a fire is finished) does such 
> a great job of cooking: it heats whatever you put into it in three ways: by 
> contact with the floor of the oven, by convection around the container, and 
> by radiation in the infrared, from the firebrick floor, sides, and top. 
> 
> 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. 
> 
> Susan Kline
> 

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