During the colder months, humidity often becomes uncomfortably low, so homeowners turn to humidifiers. Parents use humidifiers to help congested children breathe easier. Humidifiers have a good safety record, but should be used with distilled water. According to the FDA, humidifiers can release minerals from tap water into the air. The use of distilled water prevents this possible health hazard.
Ultrasonic and impeller humidifiers most often get the blame for spraying minerals and microorganisms from their tank to the air. According to the FDA, they have not declared this a hazard to health, but do recommend distilled water and regular cleaning of humidifier tanks. Distilled water has very small amounts of minerals, but distillation removes enough minerals to make it much better for humidifiers and decrease mineral particles significantly.
In addition to the possible release of mineral particles, tap water leaves white crusty lime deposits inside the tank of the humidifier. These deposits provide a good surface for microorganisms to flourish, and then get introduced into the air. Some users have reported a white dust deposited where humidifier spray reaches.
Two types of humidifiers produce the most mineral particles in the air. An ultrasonic humidifier uses ultrasonic vibrations to create a cool mist. The impeller type works by using a rotating disc to spray a cool mist into the room. Less likely to cause mineral dispersion are steam vaporizers, which heat water to make a steamy mist. Evaporative humidifiers use a fan to blow air through a moist filter or other material. All types need regular cleaning to reduce microorganisms.
Cleaning reduces the risk of problems from humidifier use. Empty the tank, dry it, wipe surfaces and then refill with fresh distilled water daily. Use the disinfectant recommended by the manufacturer or a solution of 3-percent hydrogen peroxide. Don't let water stand in the humidifier, and if you put it into storage, make sure all of the parts are dry.