Dehumidifiers improve air quality
Dehumidifiers remove excess moisture from the air in basements, crawl spaces, storage areas, and from homes without air conditioning. A relative humidity above 50 percent makes a home's environment feel uncomfortable and can promote the growth of allergy-triggering mold and mildew. The U.S. Environmental Protection Agency (EPA) says that the ideal humidity range is between 30 and 50 percent. While dehumidifiers are often thought of as a summertime appliance, they should be used year-round to keep humidity in check to prevent the growth of mold and mildew.
A dehumidifier uses a fan to blow humid air over a set of chilled coils. This condenses the moisture in the air into water, which is then drained into a collecting basin or hose. The air that returns to the room is both drier and warmer. Manufacturers classify dehumidifiers by the maximum amount of moisture they can extract from the air in a 24-hour period. Portable dehumidifiers designed to be used in a single room generally have a capacity in the range of 30 to 70 pints per day. Models designed to dehumidify an entire basement or a whole house can remove more moisture -- some can wring out more than 100 pints per day -- and are equipped with more powerful fans so that they are effective over a larger area.
While any homeowner can install a portable or basement dehumidifier, a whole-house dehumidifier installation is more complex. Just like central air conditioning or forced air heating systems, a system of ductwork is needed to collect the humid air and redistribute it after the moisture has been removed. If you already have central air or forced air heating, your home has the needed ductwork. Otherwise it will need to be added, and that cost might make a whole-house solution a whole lot more expensive and a whole lot less appealing or practical. Either way, experts say that if you are contemplating a whole house system, installation is best handled by a qualified HVAC contractor.
Air conditioners also remove humidity from the air, though some are better in that regard than others. Some window air conditioners have a special dehumidifier mode that will reduce humidity without cooling. See our air conditioners report for more information.
Portable dehumidifiers have a container to collect the condensed water, which needs to be emptied by hand. When the container is full, the unit will automatically turn off until the container is emptied. Though larger containers are heavier when full, experts generally say that units with large containers are preferable because they don't have to be emptied as often.
Larger basement and whole house dehumidifiers typically lack collection buckets and have to be connected to a drain via a hose. Most rely on gravity to drain, but some have optional pumps that can be purchased as an accessory.
Many portable dehumidifiers also offer a hose hookup that allows you to connect a hose to a floor drain, using gravity to empty the condensed water continuously. Some models are also equipped with a pump to expel the water into to a sink or out a basement window, but reviews for current pump-equipped portable dehumidifiers are lackluster. Instead, most suggest buying a top-rated portable dehumidifier and adding a separate condensate pump.
Finding the best dehumidifiers
To identify the best dehumidifiers, editors evaluated reviews from experts such as ConsumerReports.org, DehumidifiersBuyersGuide.com and HVAC-For-Beginners.com. We also looked at thousands of owner-reviews at retail websites -- particularly important in the case of dehumidifiers as reliability has been a sore spot in past years. We considered performance, ease of use, noise and reliability in evaluating models. The end result are our picks for the best portable and whole house dehumidifiers.