Dehumidifiers - How they Work & What They Do

Dehumidifying household appliances have been around for a long while now, reducing the level of humidity in the air and making life more comfortable for people in wetter climates. Over the years, dehumidifier units have grown in size and energy consumption. Large units designed to draw moisture and reduce mold in basements can be big energy draws and are often left on for days or weeks at a time. The Energy Star program examines these units and rewards those that are at least 10 to 20% more energy efficient than their counterparts with the blue Energy Star logo.

Dehumidifiers Qualified by Energy Star

Dehumidifiers qualified for the Energy Star program operate at better levels for the environment, as well as saving a homeowner money in costly utility bills. They do this through better quality components such as energy efficient coils, compressors, and fans. As the dehumidifier draws moist air over refrigerated coils, condensation is extracted. The EPA examines the amount of this moisture removed from the air over a specified period of time, then compares the energy cost required to remove that moisture in Kilowatt Hours (KWh). Models that save energy will reduce pollution, help the environment, and save homeowners money.

Energy Saving Tips - Dehumidifiers by Energy Star Replacing an inefficient dehumidifier with an Energy Star rated model could save enough electricity to power the average refrigerator for half a year!

Since air conditioning units and central air systems already act as dehumidifiers, adding a dehumidifier to your home could reduce the amount of energy needed to chill the air to a desired temperature. In this respect the dehumidifier begins to pay for itself in decreased cooling costs on top of doing its own job, not to mention the reduction in wear and tear on air conditioning equipment.

As for water collection and drainage, there are two types of portable dehumidifiers. The first is a collection unit, where a removable tank or collection receptacle is attached to the back of the dehumidifier. As condensation is collected the full basin must be removed and drained, and most of these units have sensors that shut the unit off before it overflows. Most water collection dehumidifiers however can be adapted into the second type, which are connected to plumbing or utilize a water pump to drain themselves. A pipe or hose can be fitted to run to a drain, or even outdoors, as the water extracted from the air is by a dehumidifier is actually distilled and can be treated as greywater in a household.

Dehumidifiers can also have top-mounted air discharge, and these can be placed against a wall to keep them out of the way. Face-type discharge systems should be kept closer to the center of a room to allow for good air circulation to and from the unit. Dehumidifiers obviously work best in enclosed areas or spaces, or in basements where their moisture eliminating properties can be maximized. Leaving windows or doors open to the outside air all but eliminates a dehumidifier's usefulness. They also work best when located in areas free of dust or floating air particles, as they do not perform like air cleaners.

Choosing and Sizing a Dehumidifier for Specific Rooms or Spaces

The capacity of dehumidifiers is measured in units of pints per 24 hours. The two basic factors needed to determine the capacity are square footage and room condition. The Energy Star website credits the Association of Home Appliance Manufacturers (AHAM) with the following sizing chart below:

Room Condition Before Adding Dehumidifier Area in Sq. Feet
500 1000 1500 2000 2500
Moderately Damp
Room is damp and has a strong musty odor, but only when the weather is humid.
10 14 18 22 26
Extremely Damp
Room is damp and always has a strong musty odor. Damp spots may show on the walls or floor.
12 17 22 27 32
Room smells and feels wet to the touch. Wall or floors show condensation (sweat) and seepage may be present.
14 20 26 32 38
Extremely Wet
Wet floor and high load conditions.
16 23 30 37 44


Manufacturers of Energy Star Rated Dehumidifier Models & Systems

Dehumidifiers achieving the Energy Star seal of approval from the EPA will always bear the blue logo. Search for these models whenever looking for any type of high-quality, energy-saving appliance. A list of dehumidifier manufacturers who produce Energy Star qualified models can be found below:

Air Cleaning Equipment
Danby Products Inc.
De'Longhi America, Inc.
Dri-Eaz Products, Inc.
Electrolux Home Products
GE Consumer & Industrial
Grainger Industrial Supply
Haier America
Heat Controller Inc.
LG Electronics, Inc.
Midea USA Inc.
Munters Corporation
Ningbo Royal Sovereign
Samsung Electronics
Soleus Air International
Sunbeam Products, Inc.
Therma-Stor Products
US HomeProtect, LLC
W.C. Wood Company, Inc.
Whirlpool Corporation

Other Features to Consider in a Dehumidifier

When selecting a home dehumidifier, certain features may be more important to you than others. One of the most common and important features would be an electronic timer, allowing you to set the times and hours of operation for the unit. If you happen to live in an area offering off-peak electric rates, you can use the timer to your advantage and save money on utilities.

Varying pump and fan speeds can also help you keep your dehumidifier running full speed when you need it to, but quiet down during times you're going to be in the home with it. Constantly emptying your dehumidifier can also be tiring, so consider a unit with a pump or automatic drainage system to keep the water receptacle empty. Finally, every dehumidifier will use some sort of air filtration system, and these filters should be easily accessible and (ideally) removable as well, making for easy cleaning and maintenance.

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