Humidifiers, asthma and allergies

If you or your child has asthma or allergies, talk to your doctor before using a humidifier. Increased humidity may ease breathing in children and adults who have asthma or allergies, especially during a respiratory infection such as a cold. But dirty mist or increased growth of allergens caused by high humidity can trigger or worsen asthma and allergy symptoms.

When the air's too damp: Dehumidifiers and air conditioners

Just as air that's dry can be a problem, so can air that's too moist. When humidity gets too high — common during summer months — it's a good idea to take steps to reduce indoor moisture. There are two ways to reduce humidity:

  • Use an air conditioner. Central or window-mounted air conditioning units dry the air, keeping indoor humidity at a comfortable and healthy level.
  • Use a dehumidifier. These devices collect excess moisture from the air, lowering humidity levels. Dehumidifiers work like air conditioners, without the "cooling" effect. They're often used to help dry out damp basements.

Keep it clean: Dirty humidifiers and health problems

Dirty reservoirs and filters in humidifiers can quickly breed bacteria and mold. Dirty humidifiers can be especially problematic for people with asthma and allergies, but even in healthy people humidifiers have the potential to trigger flu-like symptoms or even lung infections when the contaminated mist or steam is released into the air. Steam vaporizers or evaporators may be less likely to release airborne allergens than may cool-mist humidifiers.

Tips for keeping your humidifier clean

To keep humidifiers free of harmful mold, fungi and bacteria, follow the guidelines recommended by the manufacturer. These tips for portable humidifiers also can help:

  • Use distilled or demineralized water. Tap water contains minerals that can create deposits inside your humidifier that promote bacterial growth. And, when released into the air, these minerals often appear as white dust on your furniture. You may also breathe in some minerals that are dispersed into the air. Distilled or demineralized water has a much lower mineral content compared with tap water. In addition, use demineralization cartridges or filters if recommended by the manufacturer.
  • Change humidifier water often. Don't allow film or deposits to develop inside your humidifiers. Empty the tanks, dry the inside surfaces and refill with clean water every day if possible, especially if using cool mist or ultrasonic humidifiers. Unplug the unit first.
  • Clean humidifiers every three days. Unplug the humidifier before you clean it. Remove any mineral deposits or film from the tank or other parts of the humidifier with a 3 percent hydrogen peroxide solution, which is available at pharmacies. Some manufacturers recommend using chlorine bleach or other disinfectants.
  • Always rinse the tank after cleaning to keep harmful chemicals from becoming airborne — and then inhaled.
  • Change humidifier filters regularly. If the humidifier has a filter, change it at least as often as the manufacturer recommends — and more often if it's dirty. Also regularly change the filter in your central air conditioning and heating system.
  • Keep the area around humidifiers dry. If the area around a humidifier becomes damp or wet — including windows, carpeting, drapes or tablecloths — turn the humidifier down or reduce how frequently you use it.
  • Prepare humidifiers for storage. Drain and clean humidifiers before storing them. And then clean them again when you take them out of storage for use. Throw away all used cartridges, cassettes or filters.
  • Follow instructions for central humidifiers. If you have a humidifier built into your central heating and cooling system, read the instruction manual or ask your heating and cooling specialist about proper maintenance.
  • Consider replacing old humidifiers. Over time, humidifiers can build up deposits that are difficult or impossible to remove and encourage growth of bacteria.
May. 18, 2013 See more In-depth