Q: I replaced our 15-year-old functioning-but-energy-consuming dehumidifier with an LG 50-pint model.
There are no guidelines in the manual, and the people at Lowe's didn't seem to have an answer when I asked what size to buy. Isn't there some sort of square footage involved? I asked. I was told, Buy the biggest one.
Generally, I thought I had a mostly dry basement, but with my new dehumidifier, at the preset level of 50 percent, the reservoir is filled by the end of the day. So this machine is working, like, all day. I can't seem to wrap my head around what is an acceptable humidity level. Do you know what percentage is recommended?
A: Was the biggest one also the most expensive? Next time you are in any store and someone tells you to buy the biggest one, move on to the next store.
Or, at least someone who reads the store's own literature, because Lowes.com has an absolutely fine guide on picking the right dehumidifier.
Dehumidifiers are rated according to their capacity: the number of pints of water removed in a 24-hour period.
The Lowe's site uses the Association of Home Appliance Manufacturers' dehumidification selection guide, based on square footage and moisture.
For example, a dehumidifier in a 500-square-foot wet area needs to have a capacity of 14 pints per day. One 50-pint-capacity dehumidifier I saw advertised claimed it was designed for a medium-size space but then added that it could handle up to 3,000 square feet.
I keep my relatively dry basement at 40 percent relative humidity, using a 60-pint-capacity dehumidifier. Instead of having to dump out the reservoir that holds the collected moisture, I have it draining into a plastic splash guard that empties into the sump.
Humidity is most often talked about in terms of relative humidity, according to EnergyStar.gov. Relative humidity is the amount of water vapor actually present in the air compared with the greatest amount of water vapor the air can hold at that temperature.
The optimum RH level for a building is between 30 and 50 percent. Anything above may promote bacteria growth.
In colder climates, humidity levels during heating season should be 30 to 40 percent to prevent window condensation.