Humidifiers and Dehumidifiers

Aprilaire Humidifiers

Whole-house humidifiers with water-efficiency options

The most notable claim from this whole-home-humidifier company is that their units offer 50 percent more humidifying capacity than comparable products (due to fully automated controls). Installed in homes since 1954, when Aprilaire introduced the first evaporative flow-through system, the units work in much the same way today - by distributing moisture as a water vapor.

Aprilaire whole house humidifiers utilize flow-through technology and evaporative means to either trap minerals and harmful microorganisms on a replaceable moist pad or flush them down the drain with waste water. With no stagnant water, bacteria and minerals don't get a chance to build up.

Fully automated

The company points to their revolutionary automatic humidifiers as a new standard for the industry. Equipped with a computer to automatically adjust levels of indoor humidification, the automated humidifier is said to eliminate the need for manual adjustments and has been shown in tests to be three times more accurate and four times more reliable than other humidifiers.

The automatic humidifiers measure outdoor temperature changes more than 86,000 times a day and adjust indoor humidity accordingly. Models include the 350 / 360, 400, 550, 600 and 700 (formerly 768) and cost in the midrange of whole-house humidifiers. Warranties are all one year. From units for use in smaller homes (the 550) to units for use in homes with radiators or baseboard heaters (the self-contained 350/360), Aprilaire whole-house humidifiers offer something for almost every homeowner.

Water-conserving option

The best system for water conservation and power savings seems to be the 400 model. It uses 100 percent of the water entering it, and standing water is avoided because it only contains eight ounces at any time. The 400 does require twice-seasonal maintenance, but it takes about 10 minutes and consists of replacing a water panel and cleaning a scale-control insert, a float and a float panel. A safety overflow valve is installed in case of failure.

Hot or cold, soft or hard, water can be used in most situations, and only cooled water drains out. If the unit is installed on the return air duct, the company does recommend using hot water to aid in evaporation. Units used with heat pumps also need hot water.

The following table summarizes Aprilaire's offerings: Homes that aren't tightly constructed may not experience the same area coverage with humidifiers.

Gallons per hour

Home size


350 or 360


4,500 sq. feet, tightly constructed

Self-contained units can be placed in closets, heated crawl spaces or basements. Good for radiator-, baseboard- or centrally heated homes.



4,000 sq. feet, tightly constructed

Wicking technology minimizes water use and eliminates standing water. Good for homes without drains or septic systems or for homeowners interested in water conservation. Can be automatic or manual.



3,000 sq. feet, tightly constructed

Installed in living area or central heating and cooling system. Ideal for smaller homes. Can be manual or automatic.



4,000 sq. feet, tightly constructed

Labeled summer and winter settings. Fully automatic or manual control.

700 (768)


4,200 sq. feet, tightly constructed

One of the highest capacity humidifiers sold. Automatic control can be installed for manual use as well.

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