Re More on humidity control

[Bob Anderson]

I suggest that a more careful assessment of humidity levels throughout
the year is in order. For instance, I measure the humidity level with a
sling psychrometer before I tune a piano. These measurements help me
advise the customer about the humidity swings and possible remedies.

The placement of the humidistat is important(especially in a grand
piano). It is more sensitive to dehumidifiers than to humidifiers. I saw
an installation yesterday that had a dehumidifier rod directly beneath
the humidistat. In this case the humidistat thinks that it is drier than
is really the case. It will keep the humidifier running more often. It
is also important to install the humidistat upside down in a grand piano
to have the vent holes next to the soundboard. The humidistat should
also be mounted on the side of a beam with the top edge of the
humidistat even with the top edge of the beam. A typical installation(in
a grand piano) will have the humidifier as close to the center of the
soundboard as possible with the humidistat installed on the opposite
side of a


 beam from the humidifier.  The dehumidifiers will be arranged roughly
around the perimeter of the soundboard.

When you talk about people living in homes with the RH above 70% for the
overwhelming majority of the year, it makes me wonder if you are
conjecturing or if you have really carefully measured humidity levels to
confirm that statement. I have heard so many wrong conjectures by both
customers and piano technicians about  RH, that I respectfully bring it
to your attention. Even in an area like New Orleans, I have to assume
that it gets somewhat cold in the Winter. (Perhaps I'm wrong and it's a
real tropical area.) But if you have something like Winter in N.O. there
must be some use of heating which would drive the humidity down. I would
be interested to find out about exact humidity measurements with a sling
psychrometer.Perhaps these suggestions will elicit some date from you
about humidity conditions in your area throughout the year.

Bob Anderson
Tucson,AZ