Those of us who are required to heat our homes or shops in winter
should keep a humidity gauge, and read it daily.  We will soon discover
that there are drastic changes between natural summer heat, and
winter's artificial heat.

In my home, on the waters edge of lake Cayuga, humidity in summer can
be as high as 95%; by contrast, in winter, as low as 18%.  This drastic
change is very unhealthy for your piano, you, or anything made of wood.
The ideal situation would be to have a steady controlled humidity
(about 40%) year round.  Unfortunately that is not always possible.

Very old homes such as mine, are leaky, and while having and using a
humidifier can be good for your piano, furnishings and health, excess
inside humidity in winter can do serious damage to your home!

Humidified air in winter can condense on attic rafters, and between
walls, and insulation, rotting wood, and softening sheet rock ceilings.
Other disadvantages of using a humidifier are peeling paint from the
exterior of you house, ice dams on the roof, water damage on ceilings
and walls.  In addition molds and bacteria can multiply within
humidifiers unless carefully controlled.

The next best solution, would be a special climate controlled room or
box in which to keep the piano.  The humidity surrounding the piano
should be exactly the same on all sides of the piano 365 days of the
year.

Keep in mind all wood will warp if the humidity is low on one side and
high on the other.  This is true of piano sound boards, parts and pin
blocks.  Therefore, the use of internal electrical devices to raise and
lower humidity *only on one side of a piano's wood*  might do more harm
than good in the long run.  I will repeat: if one is to add or subtract
humidity, it should be done evenly, on *both* sides of the piano sound
board!

I once wrote about my solution, and will repeat it again.  I keep
plastic freezer quart boxes, filled with water between the posts on
the back of my upright piano.  In each water container I have devised
sponge wicks to further distribute water vapor.  Over the posts and
entire back of the piano I have securely taped thin plastic.  The
plastic confines the mild moisture to the sound board area during the
dry season.  Inside the bottom of the piano are an equal number of
containers of water.

There are two humidity gauges.  One inside the piano and one under the
transparent plastic on the back.  The humidity usually remains about
34% -- not the ideal 40%, but better than nothing.  Still, the winter
tuning changes a bit, due to some shrinkage of the wood.

Keep watching these humidity gauges.  As the humidity rises to the
40% range, remove the water containers immediately, and replace them
with automatically controlled heat rods, behind the plastic cover.
The thin plastic cover makes little difference in the pianos tone.

Keep careful watch of the humidity gauges.  When the humidity starts
to rise, turn on the heat rods, and/or use air conditioning to drive
off excess moisture.  It will help, but is not the perfect solution.
I have the heat rods connected to a humidity sensor which can be set
like a thermostat.  The heat rods turn on automatically when the
humidity under the plastic cover is above 45% and automatically turn
off when the humidity is lower than 40%.

Keep the front of the piano closed up as much as possible during severe
changes in humidity.  Keep the cover over the keys, and the music rack
closed tightly.

One more warning: When humidifiers were in vogue, I thought it would be
the perfect solution for out-of-tune pianos.  I was wrong!  I ran the
humidifier, and got the humidity up to 50% and kept it there all
winter.  Great for the piano, I thought.

I first noticed something was wrong when I went to the attic to gather
the Christmas decorations.  They were a soggy mildewed mess!  I did not
give it much more thought until later.  I looked at the outside of my
house and was shocked to find that the external paint was peeling off
the house.  To make matters worse, the sheet rock in the upstairs hall
ceiling started to fall down!  All the effects of trying to add more
humidity to an old house.  It was a hard lesson to learn.

The next home I have will be tight and climate controlled.  (At least
the music room will be.)

Bruce Clark