Is Your Humidifier Making You Sick?

Home humidifier sitting on a floor and plugged into wall

Bart Everson / Flickr / CC BY 2.0

Dry winter air causes a broad range of health issues from nosebleeds to dehydration, from dry skin and cracked lips to pneumonia. The standard preventive measure for these dry-air health problems is to use a portable humidifier, which helps avoid these health problems by putting much-needed moisture back into the air you breath. All too often, though, a humidifier can do more harm than good. Health symptoms that are sometimes caused by humidifiers include:

  • Allergies
  • Asthma flair-ups
  • Coughs
  • Flu-like symptoms
  • Lung and sinus infections

This checklist will help you figure out if the one you use is making sick.

  • 01 of 07

    A Safe Humidifier Is a Clean Humidifier

    When a humidifier causes health problems, it is almost always because it contains bacteria and molds that can trigger allergy symptoms, asthma symptoms, or even lung affections. It is easy to understand how this can happen because the nature of a humidifier is to hold standing water, to evaporate it through a system of damp wicks, and to blow that moistened (and possibly infected) air out into the room to raise the ambient humidity levels in the room.

    That is all well and good if the water being evaporated is perfectly sterile. But the standing water reservoir is a natural place where molds and bacteria can multiply, and the moment the reservoir or saturated wick in your humidifier becomes infected, your appliance has just become a distribution system for germs and molds. As germs and mold spores are blown into the air, they are on the hunt for new moist, warm places to take up residence—often your lungs or sinus cavities.

    This may sound so scary that you wonder why anyone would ever use a humidifier. Fortunately, it's fairly easy to prevent your humidifier from becoming a petri dish for bacteria—just clean it regularly. If using a humidifier daily, a cleaning routine repeated every three days should keep your air perfectly healthy.

  • 02 of 07

    Cleaning a Dirty Humidifier

    To deep clean your machine, first, disinfect its base using 3-percent hydrogen peroxide or white distilled vinegar. Here's what to do:

    1. Unplug the humidifier unit from the wall outlet.
    2. Remove the unit's water tank and filter.
    3. Pour a generous amount of hydrogen peroxide or white distilled vinegar into the base of the humidifier
    4. Use a clean toothbrush to scrub away film and mineral buildup.
    5. Let the liquid sit in the humidifier’s base for at least 10 to 30 minutes, then pour out the liquid.
    6. Rinse by adding and swishing fresh water to the base. If any mineral residue is left, repeat the entire process.
    7. When the base is clean, let it air-dry.
  • 03 of 07

    Cleaning the Wick

    Cool-mist humidifiers don't have an evaporative wick, but most larger floor models operate by a wicking pad that soaks up water to facilitate its evaporation. This wick can either be a flat pad or a cylindrical pad that fits around a rotating drum.

    Whatever type of wick you have, remove it from the humidifier each time you clean it and thoroughly rinse it in clear water. Don't use any cleaning solutions on the wick. If the wick has become caked with white mineral deposits, replace it with a fresh wick pad.

  • 04 of 07

    Cleaning the Tank

    A humidifier's water tank is also a haven for bacteria and mold.

    1. Mix a solution of four parts water to one part hydrogen peroxide (3 percent) in the tank.
    2. Allow the solution to remain in the tank for at least 30 minutes. Empty the solutions
    3. Rinse thoroughly with clean water and let the tank air-dry.

    After cleaning, to prevent bacteria and mold growth, replace the water in your tank daily and repeat the cleaning process weekly.

    Continue to 5 of 7 below.
  • 05 of 07

    Is Your Humidifier Still Making You Sick?

    If your humidifier is still aggravating your sinuses and throat even after it has been thoroughly and regularly cleaned, it's time to stop using tap water and switch to distilled water.

    Tap water contains minerals and contaminants that encourage bacteria growth. These minerals are especially prevalent if you have hard water—it's these minerals that cause the white dust that's left behind in the tank and on the evaporative wick after the water evaporates away. Distilled water is produced by an evaporation process that captures only the water molecules and leaves behind mineral deposits.

    Combined with regular cleaning of the humidifier, tank, and evaporative wick, using distilled water should eliminate any health problems you experience from using a portable humidifier.

  • 06 of 07

    You May Need a New Humidifier

    Over time, there can be such a buildup of mineral deposits that a portable humidifier can no longer work efficiently. When this happens, it's time to buy a new humidifier. Where there is a noticeable buildup of mineral deposits, a buildup of bacteria is almost certainly present, as well.

    Now is the time to switch to an antimicrobial humidifier. These units can purify stored water, so they produce a cleaner and healthier mist. To keep your machine in tip-top-shade, follow instructions for cleaning. Consult consumer advocacy sources, such as Consumer Reports, for advice on the best portable humidifiers.

  • 07 of 07

    Whole-House Humidifiers

    If your main HVAC system has a built-in humidifier feature, its components need to be cleaned and maintained regularly, just as with a portable humidifier. Whole-house units can be even more prone to health problems than portable units. Consult the instructions for your furnace/air conditioner system for directions on how to clean and maintain a whole-house humidifier unit.