During the cold winter months, the relative humidity inside of a home can dip to less than 15%. In order for the air indoors to remain at a comfortable temperature, the relative humidity should hover around 30 to 35%. In order to achieve a desirable level of humidity, a humidifier may be necessary. A humidifier is a device or machine that is used to keep the air moist inside an enclosed space.

Humidifiers are sold as stand alone units-either tabletop or floor models. They may also be mounted onto a furnace or inside the ductwork.



Wick Humidifiers

The most common type of humidifier used in the home is a wick, or evaporative humidifier. A wick humidifier consists of several basic parts including the:

  • Wick or filter
  • Fan
  • Reservoir.

How Wick Humidifiers Work

Once the humidifier is turned on, the water travels from the reservoir to the filter. The reservoir, basically a large bucket or container, is filled with water prior to use. The filter absorbs the water from the reservoir as the fan blows on the filter.

As the water evaporates, it transforms from a liquid state to a gaseous state called water vapor. The resulting water vapor moisturizes the air in the room. The rate at which the water evaporates depends on the relative humidity in the room. The lower the humidity, the higher the evaporation rate and vice versa.

Other Types of Humidifiers

Other types of popular humidifiers include:

  • Impeller
  • Steam/Vaporizer
  • Ultrasonic.

Impeller Humidifiers

Impeller humidifiers distribute droplets of water into the air in a cool fog that dissipates into the air as it exits the machine. The droplets are formed via a rotating disc inside of the unit that directs water towards a diffuser. The diffuser breaks the water down into small droplets.

Steam/Vaporizer Humidifiers

Steam humidifiers are considered one of the least expensive types of humidifiers, but they tend to be noisy. Steam or vaporizer humidifiers work by boiling water inside the unit and releasing it as steam into the air. A major benefit to steam humidifiers is that medicated inhalants may be added to help reduce coughs.

Ultrasonic Humidifiers

With ultrasonic humidifiers, a metal diaphragm vibrates at an ultrasonic frequency to create water droplets. The water droplets are released into the air in a chilly fog. Ultrasonic humidifiers are considered the quietest of all humidifiers, but they may be higher maintenance than most. To avoid bacteria build-up, they should be cleaned regularly.