How can mold grow in a duct system and what problems can it cause?
Mold spores require a stable temperature, a food source and moisture to live and reproduce. Dust and dirt that go through the filter are a good food source. The furnace/air conditioner is designed to maintain a comfortable temperature, and moisture is available from humid conditions in the environment, the humidifier in the furnace or the cooling coils in an air conditioner. Live molds can release spores that will trigger allergic or asthmatic reactions, sometimes severe, in about 10% of the population. Mold both living and dead can produce toxins that may cause short term allergic reactions. Long term exposures to low levels of some mold toxins can result in permanent chemical sensitivity to common compounds in the environment.
