The air duct system in a house acts as its respiratory system. Dust, dirt, debris, pollens and microbial growth which accumulate inside of air ducts, hidden from view, literally “congest” the system and make it difficult for the house to “breath” properly and function efficiently. In fact, a 1987 ASHRAE study concluded that maintaining system cleanliness would reduce average operating costs by 10 to 25 percent.
More than 70 percent of all Indoor Air Quality (IAQ) problems involve the HVAC system. Dirty air ducts are an ideal breeding ground for mold spores, mildew, bacteria (including Legionella) and other health threatening microbial growth. Dirty ductwork can also result in higher energy bills, reduced air supply and premature failure of expensive HVAC components.
Here are some harmful things that could be in your air ducts:
FUNGI One out of six people who suffer from allergies do so because of the direct relationship to fungi and bacteria in air duct systems. (Total Health and Better Health Magazines)
POLLEN Many people suffer from allergies due to pollen. Pollen is being re-circulated from your air ducts back into your home.
BACTERIA “Bacteria referred to as pathogens can cause a number of plant and animal diseases.”
DUST MITES 42,000 dust mites can be found in one ounce of dust. Interestingly enough, it isn’t the dust mites themselves that affect most people; it is the dust mite feces and the fungus and bacteria that feed on this decomposing organic matter.
Dr. Charles Best Blog 