Hi All,  Karl Peterson raised some interesting points with his
posting about trying to keep the humidity at just 30% in frigid
weather when a house doesn't have moisture barriers.  In years past,
we have had similar problems here in New Jersey, but the winters have
been quite mild for the past few years.  So, I have a tendency to
forget the ice that formed on the inside of the storm windows and
doors when it got really cold and I was using humidifiers to keep the
humidity at 35%-40% in just one room; my living room -- where I have
my main shop.  (I can feel people cringing... but it's true.)

This year, I bought a new humidifier that doesn't use heat to
disburse the moisture.  Instead, it uses centrifugal force to break
the water up into tiny molecules, and then forces them into a stream
of fast moving air that's sucked in from the room.  I'm not sure why
this method of putting moisture into the air is more efficient, but
it's a heck of a lot cleaner than any humidifier that I've owned that
uses heat in any way, shape, or form.  Maybe it has to do with the fact
that the air doesn't cool almost as soon as it leaves the humidified.
Maybe it's more 'natural'.  Whatever it is, it doesn't make the room
feel damp, and moisture didn't 'collect' on the frozen windows even on
the coldest days this year.

However, on the other side of the coin, we have a heat-type humidified
in our bedroom, and one morning I went outside and saw beads of frozen
water, coming from the small vent holes in the storm windows, that had
trickled down the side of the house (from the second story where the
bedroom is located).  Making the situation even more interesting was
the fact that the bedroom next to our room, which has no humidifier,
had no frozen water beads.  (We do keep our bedroom door almost fully
closed at night.)  So, it was clearly the moist warm air from the
heat-type humidifier that was causing the difference.

I suppose the point of all this is that the new type of humidifier
(if it is a new type) does accomplish the goal of keeping humidity
in the room (I set it at 45% this Winter) without the annoying
condensation that has always resulted when a heat-type humidifier was
used.  Is this type of humidity better for a piano?  I don't know.
But, it seems like almost a no-brainer.

My thought is that the heat-type humidifiers spew what might be
referred to as 'clusters' of water molecules into the air.  Those
clusters cool pretty rapidly and, being heavier than air, have a
tendency to condense on anything that is colder than the ambient
temperature in the room.  And, since our skin is sensitive to changes
in wetness in the air, a room that's humidified with a heat-type system
'feels' a little damp.  Also, I can assure you that the room that's
humidified with the 'cool air' type humidifier does not feel damp at
all.  In fact, it feels quite normal.

So, this might be something to think about when you purchase your next
humidifier.  I was a little surprised to find that the cool air type
was about the same price as the warm air type.  And, during this
Winter, I found that the two used almost exactly the same amount of
water per hour.

You might be asking why it is that I included "player piano" in my
subject, whereas Karl just said "piano".  It's my feeling that a player
piano is even more sensitive to changes in temperature and humidity
because there is so much 'un-sealed', relatively 'soft' wood in the
mechanism.  And, that wood will soak up moisture faster than hardwood
or wood that is sealed.

I also believe the same is true for the bellows cloth, and that
'changes' in the humidity level will cause the material to 'take a set'
faster than material that remains at the same basic humidity.  My
unscientific thoughts on the matter.

Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA