There's been a slightly musty odor in the basement lately and we've talked about getting a dehumidifier to see if it'd help. While in Massachusetts, Evelin picked up a stray catalogue at her parents' and noticed the eva-dry portable dehumidifiers. Instead of paying the $30 or so the catalogue wanted, I checked Froogle and found the same things available for $16 or so.
We've had three of them in the basement for less than a week and the mustiness seems to be completely gone.
Basically, it's little sealed balls that wick moisture out of the air; when they get saturated (which is evident because they change color from blue to pink), you just plug in the unit and it discharges the moisture from the balls.
I'm guessing it uses heat to reënergize the balls, but I won't know for sure until we try. We also think we'll try to discharge them outside; the instructions suggest discharging in a bathroom or somewhere else where the locked in moisture won't do any damage, but outside sounds best to me.
ADDENDUM: A lot of people see to stumble on my site by googling "eva-dry instructions" only to find this entry.
Well, the instructions are pretty simple. Hang them in the basement, closet, wherever, and check them every week or so. If the little balls in the window are pink, then plug the unit into an outlet and let it dissipate the heat.
I've found that the three in different parts of the basement need recharging every 10 to 12 days and it takes a good 14+ hours to bake the things back to blue. I plug them in outside in the morning and try to remember to bring them back in before I go to bed. (1 September 2004)