Air ducts provide a common harbor and distribution mechanism for biological air contaminants, though the U.S. Environmental Protection Agency (EPA) does not address this. EPA does report that molds can be found almost anywhere and can grow on virtually any substance when moisture is present. Molds produce tiny spores to reproduce, just as plants produce seeds. Mold spores waft through the indoor and outdoor air continually. When mold spores land on a damp indoor spot, they may begin growing and digesting whatever they are growing on in order to survive.
Often in older homes, forced air heaters have been operated for years with dirty filters or with no filters at all. The accumulated dust on the inner duct surfaces is often oily or moist and may contain mites or various species of molds or fungus. In new homes where airtight construction methods are employed for enhanced energy conservation, the growth of mold spores has become recognized as a significant indoor air quality hazard.
There is no practical way to eliminate all molds and mold spores in the indoor environment; the way to control indoor mold growth is to control moisture. Molds can trigger asthma episodes in individuals with an allergic reaction to mold. If mold is a problem in your home, you must clean up the mold and eliminate sources of moisture.
Recommendation by your professional inspector to clean you air ducts should be heeded to help provide a safe and healthy home.
Since 1976, CREIA, a non-profit voluntary membership organization has been providing education, training, and support services to the real estate inspection industry and to the public. Inspectors must adhere to CREIA's Code of Ethics and follow the Standards of Practice developed by the association and recognized by California. It requires members to successfully pass a written test of property systems and complete 30 hours of education each year.
CREIA is dedicated to consumer protection and education. To locate a qualified CREIA inspector near you, call CREIA at 800/388-8443, or visit the CREIA Web site at www.CREIA.com.