What is the Stale Smell Coming from the Humidifier?

How Much Is Too Much?

• The EPA recommends keeping indoor relative humidity below 50 percent. If you smell a musty odor when the humidifier is on or especially when it's off, that's an indication that things are getting too damp. Other signs of too much humidity and moisture include condensation on the inside of windows or on walls, and moist carpeting, curtains or any other fabric in proximity to the humidifier.

Cleaning a Humidifier

• Humidifiers need cleaning regularly -- at least every three days. Empty the reservoir and wipe it dry as best you can or let it air dry. Wipe the surfaces of the humidifier to remove any accumulated dust. Unplug the humidifier and wipe clean every part of the unit that you can access. The Consumer Products Safety Commission (CPSC) recommends sanitizing the reservoir every 7 days by filling it with a weak bleach solution and then rinsing.

Dealing With Mildew

• If you detect a musty smell, discontinue use of the humidifier until the smell disappears. If it doesn't, try to detect where the smell is coming from and dry the area thoroughly. Increase air circulation throughout the house. If you suspect that drapes or other decorative items may be growing mildew, wash the items in hot water and dry them thoroughly. Clean any visible mildew by scrubbing it with a bleach solution and drying the area completely.

Recommendations

• Only use the humidifier when members of the household begin to complain of irritation or discomfort from dry conditions and then only at night to help people sleep more comfortably. The CPSC recommends operating the humidifier near an air register so the air can continue to circulate and doesn't become stagnant.