For your family's optimal health and comfort, your home's relative humidity levels should range from 30 to 50 percent in the winter and from 40 to 50 percent in the summer. But keeping humidity at these levels often demands mechanical assistance. For example, on sultry summer days, when indoor humidity rises above the comfort range, many people turn on air conditioners or dehumidifiers to help dry the air. And when the dry winter heating season sets in and drops relative humidity to skin-chaffing lows, boosting the humidity usually calls for a humidifier. Here we'll take a closer look at humidifiers: the main types, how they work, and what you should know if you're shopping for one.
A humidifier is simply a device that puts water vapor into a home's air. Depending upon its water output capacity, it may serve a single room or the entire house. Room-size humidifiers are referred to as "tabletop" units. To humidify a whole house, you need either a freestanding cabinet "console" unit or a "central" humidifier that ties into the home's forced-air heating system.
Tabletop and console models are relatively inexpensive, easy to move from one room to another and easy to hook up. Both types must be filled manually--usually on a daily basis. Regardless of the method they use to humidify air, tabletop models run from about $19 to $70, consoles from $75 to $150. Tabletop units output from 2 to 4 gallons per 24 hours. Small consoles output 8 gallons per 24 hour period--these can handle up to a 2000 square foot area. A large console may output 14 gallons, enough to humidify a 3,250 square-foot house.
Central humdifiers are hooked up to the heating equipment and water is piped directly to them, so they're out of sight and out of mind most of the time. Because they deliver humidified air directly to rooms throughout the house, they're particularly efficient . The only drawbacks are that you need a forced-air system to operate a central humidifier and humidification takes place only when the forced-air system is running (this isn't a problem in most homes because it is generally the heating process that dries out the air). Equipment prices range from about $140 to $200; installation cost depends upon the complexity of the work, but is likely to run about $100.
Most console and all central humidifiers are controlled by a humidistat that turns the unit off and on when humidity levels stray from a set range. Though a humidistat allows more or less "automatic" operation, you need to dial it up and down as the temperature changes in order to maintain fairly constant indoor relative humidity levels.
