By Barry Stone
Dear Barry,
Allow me to take exception to your recent article advising the cleaning of forced air heating ducts. I don't believe there is much evidence to support the benefits of duct cleaning. While it probably won't hurt, it bears pointing out that the U.S. Environmental Protection Agency does not recommend duct cleaning and has no evidence that it improves human health. --David
Dear David,
If you could view the interior surfaces of certain forced air heating ducts as seen by home inspectors and HVAC contractors, you would be appalled at the prospect of inhaling air that is discharged from those outlets. This is certainly not the case with all forced air systems, but in many homes occupants are unknowingly breathing air that has been circulated over layers of visible filth.
In older homes, many 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 newer 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. In these cases, air ducts provide a common harbor and distribution mechanism for biological air contaminants. To discount these realities simply because some governmental agency has failed to recognize them is to accord a higher level of trust and dependence upon bureaucratic institutions than such entities fairly warrant. Sooner or later the EPA is likely to acknowledge the potential health hazards associated with dirty warm air ducts, but the problem will continue to exist with or without that recognition.
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