Buying Guide - Dehumidifiers

Pick a dehumidifier to fit the space where it will operate.

To get a properly sized dehumidifier, you need to know the square footage of the room you want to dehumidify and have a general idea of the moisture levels.

A dehumidifier's drying capacity is measured by how many pints of water it can remove from the air in 24 hours.

Allow at least 12 inches of air space on the front and back. A dehumidifier operating in a basement will have little or no effect in drying an adjacent enclosed storage area such as a closet unless there is adequate circulation of air in and out of the area. It may be necessary to install a second dehumidifier inside the enclosed storage area for satisfactory drying action.

You are better off buying a higher-capacity dehumidifier than a unit that is too small for a room. Smaller units may run continuously without bringing the humidity down to optimal levels.  Higher-capacity dehumidifiers also can handle spaces that may be excessively damp from clothes dryers or dishwashers that add moisture to the air.

The Association of Home Appliance Manufacturers (AHAM) sets the standards for sizing dehumidifiers to match a homeowner's needs.  Most manufacturers print an easy-to-follow sizing chart on the packaging boxes of their dehumidifiers. The chart will help you pick a size to match the space in your house.  Please use the following as a generic guide:

DEHUMIDIFICATION SELECTION GUIDE

Selecting the right dehumidifier for your home is important in the buying process. See the chart at the bottom to determine which pint size is best for your moisture problem.

Dehumidification variables also include such other factors as climate, laundry equipment, number of family members, number of doors and windows, and degree and intensity of area activity.

Consider the unit's bucket size.

Dehumidifiers with larger tubs or drip pans need to be emptied less often. But expect to pay a little more for the convenience. A rule of thumb is that the more water a dehumidifier can extract and hold, the more it is likely to cost.

Most portable dehumidifiers are equipped to be self-draining, and come with a drain hose connection. A garden hose may do. But the dehumidifier will need to be placed in an area where the hose can empty water, such as a basement floor drain or above the sink in your laundry room.

Choose a humidifier with automated controls for monitoring and setting humidity levels.

The optimal relative humidity in a home should be between 40 percent and 50 percent in the summer, and 30 percent to 50 percent in the winter.

Dehumidifiers with built-in hygrometers measure relative humidity and display the number. An adjustable humidistat allows you to dial a desired humidity level, and the unit will automatically maintain it.

Opt for a dehumidifier that can function at low temperatures.

Unless you live in a climate that is warm all year, consider a unit with an automatic defrost feature. The heat-exchange coils on a dehumidifier can frost over when indoor temperatures drop below 65 or 60 degrees Fahrenheit.

This will cause your dehumidifier to work less efficiently or stop removing moisture altogether. Although you may pay a little more for the automatic defrost feature, it will spare you the expense of replacing a unit damaged from iced coils.

Feature Glossary

Quiet operation. Noise can be a nuisance, especially if the dehumidifier is in or near a bedroom. Dehumidifiers with two-speed fans run quietly at lower humidity levels. They also save on energy costs.

Mobility. Make sure your new dehumidifier comes with casters, so it can be rolled from room to room. A long power cord will enable you to put the unit where you want it.

Automatic shutoff. An overflow protection valve will cause the unit to switch off when the tub is full and needs to be emptied. This is a key feature to have on any model you choose. Some dehumidifiers have indicator lights to show when the bucket is full.

Energy efficiency. Dehumidifiers that carry the Energy Star label will save money on utility bills. Dehumidifiers certified with the government-sponsored label are guaranteed to use less energy and run efficiently.

Washable filters. Some models have filters that protect the coils from dirt and dust. Make sure you can easily remove the filters and wash them, a task you should do about twice a month. With careful maintenance, you can replace the filters less often.

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