re: dehumidify basement?
13 may 2002
>any ideas on how to dehumidify an unfinished basement, short of going out
>and buying a dehumidifier? thanks!
the yearly average air (and basement) temp is 54.3 f in phila. at 50% rh,
this corresponds to a dew point of (460+54.3)/(1+(460+54.3)ln(0.5)/9621)
= 36 f. you might turn on a basement fan whenever the outdoor temp is less
than 36 f and turn it off when the basement rh drops to 60%, with grainger's
$16 5e266 line voltage thermostat and herbach and rademan's ((800) 848-8001
http://www.herbach.com) $4.95 navy surplus humidistat, item # tm89hvc5203,
which has a 20-80% range, a 3-6% differential, and a 7.5a 125v switch that
can be wired to open or close on humidity rise.
with another humidistat for outdoor air, other combinations are possible:
to: 40 45 50 55 60 65 70 75 80 f...
ro: 88 74 64 54 47 40 35 30 26 %...
perhaps someone will make a smart basement fan control that figures this
out automatically (r = exp(-16.53(t-36)/(460+to))) and tries to keep the
basement dry, and warmer in winter and cooler in summer by ventilation.