Getting the most for your money from a home humidifier relies on sizing your system correctly. While portable and tabletop humidifiers are easily deployable—you can simply add or subtract the number of humidifiers running based on your needs—whole house humidifier systems require a little more precision.
Humidity Output Gallons Per Day vs. Tank Size
The power of your whole home humidifier is measured by gallons per day (GPD). GPD refers to the amount of moisture that the humidifier can put out while running continuously. This, of course, will not be the same as the amount of water you put in the tank—though that measurement is important, too. Most high-end whole-house humidifiers have a direct water line, which obviates the need for changing the tank. For home humidifiers that don’t have direct lines, you will have to continually check and refill the water tank. Consider this when choosing a home humidifier system.
Home Factors: Size and Insulation
The two determining factors in sizing your home humidifier system are size and “tightness” of your home. That is, how well insulated your house is. For example, a well-insulated home with storm doors and windows, vapor barriers and weatherstripping is a “tight home.” If you’ve recently had an energy audit and followed up on all the recommended weatherproofing measures, you likely have a “tight home.” Otherwise, you probably have an “average home.” If you have some glaring insulation issues—such as undampened fireplaces, no storm windows or doors, and poor insulation—then you have what is referred to as a “loose home.”
For a tight home, you’ll want a humidifier system with an output of about 1.4 GPD, 3.2 GPD, 4.9 GPD, 6.6 GPD, or 8.3 GPD for home sizes of 1,000 sq. ft, 1,500 sq. ft, 2,000 sq. ft, 2,500 sq. ft. and 3,000 sq. ft., respectively. For tight homes with only 500 sq. ft., you can probably get by with a tabletop humidifier.
Average homes should get humidifier systems with 0.5 GPD, 3.0 GPD, 5.5 GPD, 8.0 GPD, 10.5 GPD or 13.0 GPD for home sizes of 500 sq. ft, 1,000 sq. ft, 1,500 sq. ft, 2,000 sq. ft, 2,500 sq. ft or 3,000 sq. ft., respectively.
Loose homes require home humidifier outputs of 1.0 GPD, 4.0 GPD, 7.0 GPD, 10.0 GPD, 13.1 GPD and 16.1 GPD for home sizes of 500 sq. ft, 1,000 sq. ft., 1,500 sq. ft., 2,000 sq. ft., 2,500 sq. ft. and 3,000 sq. ft., respectively.
In summary, bigger houses with looser insulation will need home humidifiers with greater humidifier outputs. With this in mind, it’s highly recommended that you get an energy audit and improve your insulation before installing a home humidifier system. Also, be sure to consult an installer of whole house humidifiers on the specifics of your home. These figures are rules of thumb, and other factors—such as climate and ceiling height—may change your ideal home humidifier size.
Types of Single Room Home Humidifiers
When shopping for a home humidifier, it can seem like there are only two types of portable (aka tabletop) home humidifiers: cool mist and warm mist. However, the differences between the types and models of a home humidifier are far more nuanced and significant than cool vs. warm mist. Read up on the main types of home humidifiers so you know what you’re getting for your money:
Vaporizers and Steam Humidifiers
Most warm mist humidifiers are actually steam or vaporizer humidifiers. These work by simply boiling the water to create steam. The water vapor and device itself can sometimes be hot enough to burn, thus this type of humidifier has declined in popularity lately. However, newer safety features are allowing warm mist humidifiers to make a comeback. The key advantage of a steam humidifier is that the boiling process eliminates much of the potentially harmful bacteria.
A type of cool mist humidifier, impeller humidifiers separate water into tiny droplets by passing it through a spinning disc. These work much as an atomizer does. Impeller humidifiers are effective at dispersing humid air throughout larger rooms.
Evaporative or wick humidifiers are one of the most popular models. These work by forcing air through a wet medium, such as a filter, pad, or grille. The air picks up the moisture and then disperses it throughout the room. Because the air is filtered, this model is much better at removing minerals and other unwanted impurities from the vapor.
Ultrasonic humidifiers use the most recent technology. Similar to an impeller, an ultrasonic humidifier releases cool mist into the air by breaking up water into tiny droplets. This is done through high-frequency vibrations pulsed into the water via a metal diaphragm. Unlike an evaporative humidifier, ultrasonic humidifiers do not typically use fans. As such, the noise it emits is often a more constant hum, which is more tolerable to some individuals.
Each type of humidifier has its own particular drawbacks and advantages. As a general rule of thumb, cool mist humidifiers—such as impeller, evaporative and ultrasonic—are safer for households with smaller children. However, it is important to use distilled water or buy a humidifier with a good filter system to prevent the dispersal of harmful bacteria and other microorganisms. For more details on the pros and cons of each type of humidifier system, read through the individual articles on this website.