What's the recommended method to clean my humidifier?

The best way to get all the healthful benefits of using a humidifier or vaporizer is to maintain a clean humidifier during use. Nearly all humidifiers or vaporizers come with recommended cleaning and maintenance procedures listed in the owner’s manual. However, the following Use and Care instructions are also found on the EPA’s website. Additionally, the use of products called “bacteriostats” to treat the water while in the humidifier is also effective and recommended for good humidifier hygiene. These products are discussed later.in the section "Products that control bacteria and scale".

From the USEPA’s Website

Recommendations for Use and Care

  • Empty the tank, wipe all surfaces dry, and refill the water in portable humidifiers daily to reduce any growth of microorganisms; follow the manufacturer's instructions for changing water in console humidifiers. Be sure you unplug the unit from the electrical socket first.
  • Use water with low mineral content to prevent the build-up of scale and the dispersal of minerals into the air. See the box on the left for information on using water with low mineral content.
  • Clean portable humidifiers every third day. Empty the tank and use a brush or other scrubber to clean it. Remove any scale, deposits, or film that has formed on the sides of the tank or on interior surfaces, and wipe all surfaces dry. Again, be sure you unplug the unit.
  • Follow the manufacturer's suggestions on the use of cleaning products or disinfectants. In the absence of specific recommendations, clean all surfaces coming in contact with water with a 3% solution of hydrogen peroxide. If you use any cleaning or disinfecting agent, rinse the tank thoroughly with several changes of tap water to prevent dispersal of chemicals into the air during use.
  • Follow the manufacturer's directions on cleaning and maintaining console and central (furnace mounted) humidifiers. In particular, if the humidifier contains a tank, do not allow water to stand in the tank for extended periods of time, and keep the water clean.
  • Keep steam vaporizer humidifiers out of the reach of children. Steam and boiling water may cause burns.
  • Do not humidify to indoor relative humidity levels exceeding 50 percent. Higher humidity levels may encourage the growth of biological organisms in the home. Hygrometers, available at local hardware stores, may be used to measure humidity levels. Some humidifiers contain a built-in humidistat which may be adjusted to the proper moisture level. If water condenses on windows, walls, or pictures, either relocate the humidifier, lower its humidistat setting, or reduce its use.
  • Do not permit the area around the humidifier to become damp or wet. If dampness occurs, turn the output volume of the humidifier down. If the humidifier output volume cannot be turned down, use the, humidifier intermittently. Do not allow absorbent materials, such as carpeting, drapes, or table cloths, to become damp.
  • Follow the manufacturer's instructions regarding the use, maintenance, and replacement of any materials supplied with the humidifier. Use appropriate materials as recommended by the product manufacturer.
  • Clean the humidifier, as directed, at the end of the humidifying season or when the product will not be in frequent use. Before storage, make sure all the parts are dry. Dispose of all used demineralization cartridges, cassettes, or filters. Store the unit in a dry location. After storage, clean the unit again and remove any dust on the outside.
  • Stop using your humidifier and contact your physician if you have respiratory symptoms which you believe are associated with periods of use of your home humidifier, even if you are following maintenance directions.