A Humidifier is a household appliance that increases humidity in a single room or in the entire home. There are point-of-use humidifiers, which are commonly used to humidify a single room, and whole-house or furnace humidifiers, which connect to a home's HVAC system to provide humidity to the entire house. The most common humidifier, consists of just a few basic parts: a reservoir, wick and fan. Other types of humidifiers include vaporizer, that boils water, releasing steam and moisture into the air. A medicated inhalant can also be added to the steam vapor to help reduce coughs. Vaporizers are more healthful than cool mist types of humidifiers because steam is sterile and free from minerals. Vaporizers use more electricity to boil the water. Ultrasonic Humidifier has a metal diaphragm vibrating at an ultrasonic frequency and creates water droplets that exit the humidifier in the form of a cool fog silently. Ultrasonic Humidifiers should be cleaned regularly to avoid bacterial contamination, which may be projected into the air.