Some cool-mist humidifiers work by flinging water at a vaporizer, but our favorite kind uses a piezoelectric transducer. These work by using high-frequency sound waves to pound the surface of the ...

Humidifiers use one of four evaporation types: steam, evaporation, ultrasonic and impelling. Most modern humidifiers have cool and warm mist settings, each with hard water caveats. Cool mist: Cool ...