(MCT)—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 when I asked the people at Lowe’s which size to buy, I was told, “Buy the biggest one.”
Generally, I thought I had a mostly dry basement.
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 the concept of what is an acceptable humidity level. Do you know what percentage is recommended?
A: Was the biggest one also the most expensive? My suggestion is that the next time you are in any store and someone tells you to buy the biggest one, move on to the next store or find someone who has read the store’s own literature. For example, Lowes.com has an absolutely fine guide on picking the right dehumidifier for your situation.
Dehumidifiers are rated according to their capacity — the number of pints of water removed during a 24-hour period. Units with 25-, 40-, 50-, and 60-pint capacities are available.
The Lowe’s site uses the Association of Home Appliance Manufacturers’ dehumidification selection guide, based on square footage and moisture levels.
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 an area of 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, the amount of moisture or water vapor in the air, 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 generally considered to be between 30 and 50 percent. Anything above this range may promote bacteria growth.
In colder climates, humidity levels during the heating season should be in the range of 30 to 40 percent to prevent window condensation.
Many dehumidifiers include a built-in humidistat, a device that allows you to set the desired relative humidity level that you would like for the room.
Once the room reaches the desired relative humidity level, the dehumidifier will cycle on and off automatically to maintain the level.
Most dehumidifiers have top-mounted air discharge and can be placed against walls, but if you do not have top-mounted discharge, make sure the dehumidifier is located away from walls and furniture, so that air can circulate freely around the unit.
This will result in better operation of the product.
If the space being dehumidified has temperatures that typically fall below 65 degrees, you may want to consider buying a product specified for use at lower temperatures. Qualified Energy Star models are available that are rated for use at temperatures as low as 42 degrees.
The energy efficiency of a dehumidifier is measured by its energy factor, in liters of water removed per kilowatt-hour.
In general, a higher energy factor means a more efficient dehumidifier and, therefore, one less costly to operate.
©2012 The Philadelphia Inquirer
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