Humidity fluctuations are more damaging to a piano than temperature
changes.

It would be an ideal situation if we could control the temperature and
humidity surrounding our pianos.  Unless we are wealthy enough to
afford a climate controlled room, our only choice is to do our best and
make an attempt to add or subtract humidity surrounding our pianos.  At
first I felt that controlling the room humidity was the answer.  In an
active household this is nearly impossible.  Probably the easiest
method is to build a plastic tent around the piano, and control the
humidity under the tent!  Or use the method which has been successful
for me.

Obtain an accurate hygrometer which tells you the percent of humidity.
I found a nice one at Radio Shack for a few dollars.  Place one inside
the piano, and one in the room where the piano is located.  Note the
differences.

Here in central New York State where I live, the artificial heat in
winter can lower the indoor humidity to dangerous levels.  10% !  That
is equal to Death Valley!  Death to sound boards, glue joints,  and
other furnishings as well.

In contrast, the humidity of summer can reach 96%,  The constant
extremes are most damaging to a piano and wood objects, yet we must
remember many of our old pianos have endured this torture for decades,
and most have survived in various degrees of preservation.

Most people feel that an indoor humidifier is the answer.  In some
cases it is a good idea, but in very old houses such as mine, an indoor
humidifier can create very bad conditions for the house itself.  I
admit to this mistake, and must warn everyone what occurred.

I purchased a super-deluxe humidifier, and happily filled it (with ten
gallons of water per day)  and set it to produce a humidity of 48%  The
outside temperature was zero, and I was very content, and feeling quite
proud of myself until it was time to get out the Christmas decorations
from the attic. It was then I discovered everything in the attic was a
soggy mess!  The insulation was soaked and the upstairs sheet rock
ceiling began to fall down!  Next, I noticed the exterior paint on the
house started peeling.  Before the winter was over nearly 50% of the
exterior paint was gone!

Since I could not control the dryness of winter, perhaps I could
control the humidity of summer using a de-humidifier?  Wrong again!  I
purchased a quality de-humidifier and set it running.  It was removing
14 quarts of water per day from the living room, but the humidity in
the room only changed a degree or two.   In addition the heat generated
by the de-humidifier added to the 90 degree indoor temperature, making
it even more uncomfortable, and also added a substantial amount to the
electric bill.  Short of nailing all doors and windows shut, it was
impossible to instruct any of the household to keep them closed. "It is
too hot to keep the doors shut, we need fresh air"  This attitude did
nothing to assist in keeping the humidity low.  Putting the de-humidi-
fier in the front yard would have accomplished the same thing. (nothing)

A better idea is to air condition the room in which the piano is
located, but this must be done for the *entire* summer or humid season,
not only on days that are uncomfortable. This can also add a
considerable amount to the electric bill.  In most old houses, unless
it is super insulated and has a vapor barrier it is not practical.

The solution I have used is a bit unconventional, but it does a good
job.  It is important to keep the humidity equal on both sides of the
piano sounding board.  Adding piano  heat rods to reduce humidity  on
*one side* of the sound board  and not the other is not a good idea.
I feel it is not good to leave them on constantly, therefore, I have
two heat rods connected to a humidistat. (An electrical device which
turns the heat rods on and off at a set percent of humidity  43%)  One
heat rod is in the inside bottom of the piano, the other is behind the
piano sealed  under a thin plastic which covers the entire back of the
piano.

I sealed the bottom board of the piano and keep all covers closed
during the high humidity season.  This is better than nothing.  The
plastic does not interfere with the sound or tone of the piano in any
way.

During the heating season, I remove the heat rods and place several
jars of water with wicks made of old towels supported with wires,
inside and behind the plastic covering on the back of the piano. This
also helps a great deal during the winter months.  The tuning remains
quite stable, and I am pleased with the results.

Bruce Clark