Re More on humidity control

[Lance Lafargue]

This whole discussion has encouraged me to study it even further.  I carry
a regular electronic hygrometer with me and have for over ten years.  I've
owned 3 different kinds, one was not electronic.  I know the slings are
accurate.  I am told by several sources that an air conditioner can only
remove about 15-20 % of the moisture.  Also RH changes depending on the
temperature.  Louisiana is very tropical, we are surrounded by water, are
below sea level, and breed mosquitoes to export to most states in the U.S. 
I will get more data on LA humidity, avg. home temp., humidity, etc.  I
have learned from this that the U.S. is so varied in climate, and I think
we all learn what works in our area, and assume it would work everywhere. 
Winters are very sporadic here.  Occasionally we'll get weather in the
teens, but usually it stays above 40 degrees.
Lance Lafargue, RPT
New Orleans Chapter
Covington, LA.
lafargue@iamerica.net

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> From: Bob Anderson <fndango@azstarnet.com>
> To: pianotech@ptg.org
> Subject: Re: Re More on humidity control 
> Date: Thursday, August 21, 1997 9:29 PM
> 
> 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