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Re: Air conditioner noise



Our school district built a new middle school in a quiet residential area.
They installed central air conditioning with the compressors and cooling
fans installed on a one-story flat roof just in front of a two-story wall.
The noise from the compressors and fans, which was pretty bad, was
reinforced by reflection from the wall, and was causing considerable
disturbance in the neighborhood.

Of course, the first response to public complaints was that the noise was
not that bad and the people would get used to it. But the most recent
school levy only passed by one vote, and people were getting angry with the
board of education rather quickly. (The point of this paragraph is to point
out that in even in the case of a publicly-elected body, the fact that a
problem was going to take money to solve made tempers flare for a while.
The public was essentially fighting the public.)

Engineers were consulted and they built a wall around the unit so the noise
would be directed upward. The engineers felt the wall should be made of
brick, but the roof could not support the brick. So the wall was framed
with treated wood and paneled with painted corrugated steel siding/roofing
material.

This solution helped tremendously, but did not reduce the noise to zero.
Sound, of course, spreads out and cannot be totally directed. However, the
reduction of noise in the neighborhood was sufficient that people are now
happy.

The fact the compressor was already on the roof helped this situation. I am
sure a wall around your neighbor's compressor will help some, but maybe not
enough since it is at ground level. One thing that was suggested here was
to build a test wall with bales of straw. That way the engineers could test
the idea without much expense. If successful, then they would build the
permanent wall. In the end they just decided to build the permanent wall
without doing any testing.


Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817