Re: GBlist: Dustmites

Marc J. Rosenbaum (Marc.J.Rosenbaum@valley.net)
25 Feb 97 22:03:55 EST

--- Loren wrote:
As to the RH, I think it is just as much a problem to have too
little as too much. We have to use a humidifier in winter to
maintain an adequate RH or he has problems breathing.
--- end of quoted material ---
I'm curious what RH you are aiming for in the winter. My own experience in
homes I have either built or designed is that in winter, because the homes are
quite airtight, they need ventilation or they reach excessive RH (which I
define as much greater than 40% - certainly I like to see it below 50%, because
of the dust mite issue.)

The homes that need a humidifier are those which are either leaky or just so
large in ft2 per occupant that it's hard to keep RH up. I've designed the
envelope on one home that has two occupants and is 4500 ft2 and still keeps
comfortable RH levels. I would think that in the milder climate of VA
(compared to mine in northern NE) it would be less likely that a home would
need a humidifier because of higher absolute RH in the outdoor air.

BTW - Terry asked quite a while ago about the existence of studies showing
adverse health effects at low RH. I believe no one replied. Any comments
about acceptable RH range for human health?

Marc
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