Types of Humidifiers
Humidifiers can help restore the balance of moisture found in your home, particularly in dry climates and in winter. They also can alleviate discomfort and symptoms associated with colds, asthma and other ailments by keeping the air moist.
There are two basic kinds of humidifiers: cool-mist humidifiers and warm-mist humidifiers. There are three types of cool-mist humidifiers. Most popular are ultrasonic humidifiers, which use high-frequency sound waves to vaporize water. They are also the quietest type. Some ultrasonic humidifiers also can emit warm mist. Evaporative humidifiers soak up water into a wick and use a fan to expel the moisture. As a result, these models can be noisy. Although the humidifiers themselves can be inexpensive, replacing their wicks or filters is an ongoing cost. Impellers force (impel) water into the air as a fine mist; however, we found no positive reviews for humidifiers of this type.
Less common are warm-mist humidifiers (sometimes called vaporizers), which boil the water before expelling it as steam. This can eliminate bacteria that's present in the water if it's heated to a true boiling point of 212 degrees Fahrenheit, but it also means that minerals can build up in the tank and on the heating element over time. Some people prefer warm-mist humidifiers, saying the heated vapor is easier to breathe (especially if you're congested) and gently raises room temperature. But experts say the difference between the two is minimal, and doctors caution that warm-mist humidifiers pose a safety hazard because they can be tipped over by young children, scalding them.
In selecting the best humidifiers in each category, we considered the following: ease of use, noise level, refilling and maintenance convenience, and moisture output. The best of each category excelled in these areas. We also considered budget.