Here are some features of humidifiers 1 2:
*Operating Design*
- Evaporative humidifiers: uses a motor-driven fan to blow air through a wet wick, filter, or belt to evaporate water and send the moisture out into the room.
- Impeller humidifiers: uses a motor-driven rotating disc that flings water onto a diffuser, which then breaks it up into tiny droplets that float into the air.
- Ultrasonic humidifiers: produce a cool mist using two ceramic plates that vibrate at an ultrasonic frequency.
- Steam vaporizers: use electricity to turn water into steam vapor that is absorbed into the air of a room.
*Cool Mist vs. Warm Mist*
- Cool mist units: better energy efficiency than warm mist units, generates cooler air in hot weather, tends to cover more space than a warm mist unit.