professional home inspections, inc.


Humidifiers are not inspected because we feel they are potentially hazardous to your health and damaging to your home. We recommend that all central humidifiers be disconnected by turning off their electric and water supply for the following reasons:

1.    They have a tendency to overflow; which can rust out the top of the furnace's heat exchanger.

2.    The condensation they cause on windows can deteriorate the drywall and wood trim around  the windows
3.    The vapor pressure they create goes through the walls where it can condense on the insulation reducing     its insulating value or condense on the back of the exterior siding.

4.    There is a growing body of evidence linking improperly maintained central humidifiers     to a recurring     respiratory condition known as Hyper-sensitivity Pnuemontis or     "Humidifier  Lung."

    A dirty humidifier breeds fungi and bacteria and spreads them throughout the house where they are inhaled. Once exposed, a person develops hypersensitivity and contracts an illness with symptoms similar to an infectious disease characterized by fever, coughing, and shortness of breath. It is often diagnosed as something other than what it is. Dirty humidifiers and excessive moisture (70% to 80% RH) encourage the growth of mold, fungi, bacteria, viruses, and parasitic dust mites. This in turn can trigger not only humidifier lung, but also colds, allergies, asthma, and other illnesses. Doctors and manufacturers recommend that healthy people clean their humidifiers at least once a week and daily if there is a sick person in the home.

The National Jewish Center for Immunology and Respiratory Illnesses offers the following cleaning procedure:

Open windows to air out a specific room or the entire house. Combine two cups of white vinegar with enough water to produce a mist. Pour it into the humidifier and run the machine for 30 minutes so it sprays the vinegar mixture (you may wish to leave the room). Rinse the tank and the parts of the machine. Pour in clean water and run the humidifier for 3 minutes to flush any vinegar residue. Rinse again. Follow manufacturers instructions and clean all removable parts.

If you are uncomfortable with the arid Colorado air, you could purchase a room size ultra sonic humidifier with a mineral filter. This ultrasonic action usually breaks down the microbes and the mineral filter is needed to prevent the humidifier from introducing dust into the air.  If using  an evaporative type humidifier, we recommend using a bacteriostatic additive to control the growth of bacteria and fungus. Or use a vaporizer type humidifier . You are more likely to clean a humidifier next to your bed than one located somewhere in the basement.