I have a dehumidifier that is described as a 'basement dehumidifier'.
Is it appropriate to use such a unit in my crawl space? It is a
portable 70-pint unit made by Whirlpool, with a drain hookup (so it can
drain to the sump pump in my crawlspace).
If your crawlspace is ventilated to the outside no, you might as well put it
in your back yard to make the day less humid. It would be bettrer to add a
powered vent or more vent openings.
If the crawlspace is sealed like a low headroom basement, I see no reason
not to use it.
If this is a non living space, it is not necessary to lower the humidity to
comfortable levels, just lower than the dew point (during the coldest part
of the night) to prevent condensation.
As others have noted, if the area is ventilated, it will not work and
hopefully will not be needed. If it is not ventilated, then that is the
right type to use. "Basement" models should be designed to work in cool
damp areas without freezing up. One would think that all dehumidifiers
would be designed to work in cool damp conditions, but no.
I do have a vapor barrier. The crawlspace has vents but they are
sealed. I also have two high capacity vent fans on one side of the
crawlspace, and two 'moisture scrubbers' on the other side of the
crawlspace. Also have a french drain with a sump pump. I had all this
put in because I was having huge problems with moisture, with lots and
lots of mold growth. I even had soggy insulation on all the a/c ducts
down there. All this seems to have dryed things out okay (though I
haven't gone through the hot part of the summer yet, so we'll see), but
there is still an area in one corner that still seems to be staying a
bit damp. So I thought a dehumidifer in that area, drained to the sump
pump, might help.
A moisture scrubber is a box you install in a crawlspace vent. The
vent fans on the other side of the crawl space pull air through the
scrubber. The scrubber has coils in it over which air passes, and this
is supposed to condense water out of the air. The water is then
supposed to drain back out of the crawlspace. I can't say for sure
whether they works very well yet, as I had them installed at the end of
last summer, so they haven't gone through the hot part of the summer
yet. But my crawlspace has certainly been far more dry since they were
installed. They were installed by a local company here in Knoxville,
TN, but here is the url for the company that makes them:
I wonder what those fans draw, 100 watts each? 100 watts = 10$ a month
at my rates. My dehumidifier costs me 3$ a month to dehumidify 700 sq
ft. Figure your cost to run them at your rate, Sears make a
dehumidifier that runs to 45f, then you seal the crawlspace closed.
FIRST UNSEAL THE VENTS! Install a little muffin fan on one, the kind
computers use, leave run forever, use very little energy about a nite
ventilation and a good vapor barrier are the key to a dry crawlspace
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