Studies have shown that indoor air can be 2 to 5 times MORE polluted than outside air. Most disposable filters remove about 10% of these pollutants allowing 90% to enter the air system, even during the construction of a new home. The pollutants contain dust, pollen, mold spores, animal dander and much more. These materials collect in the furnace, air conditioner and duct surfaces, just as they do on the furniture and floor surfaces. The furniture and floor are cleaned regularly but the duct surfaces are hidden from view and can only be reached by specialized duct cleaning equipment. These pollutants can migrate out into the room again, or become a food source for mold and bacteria, which can thrive in this dark comfortable environment from high humidity or moisture from the air conditioner or humidifiers. Biological growth can release mold spores or toxins into the air system.

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.

Air system cleaning is a simple four step process. To view the details of this process, please view our cleaning procedures page.

Depending on the amount of contamination and its location, energy consumption could be increased. If the fan blades, evaporator coil or other control components of the system are heavily contaminated, the system may have to run much longer to cool or heat the occupied space, wasing a lot of energy.

There are 3 major parts to an air system: 1. The supply and return grills; 2. The interior surfaces of the supply and return vents; and 3. The furnace/air conditioner air handler. All 3 components must be cleaned. If only one or two of the components are cleaned, the contaminates from the 3rd component will rapidly contaminate the ones that were cleaned.

Once an air system is thoroughly cleaned, it should remain clean for 3 to 7 years if properly maintained and a high arrestance filter is installed. A standard disposable filter only stops about 10% of the airborne contaminates, allowing 90% of the dust in the room to flow back into the air system. To maintain protection against biological growth, an EPA registered biocide should be applied every 6 to 12 months by a qualified Duct Cleaning Professional.

All inside air was once outside air, so all of the dust, chemicals, pollen, insects and mold spores in the ouside air can be pulled into the air system. People shed millions of tiny dead skin cells every hour. Cooking smoke, household insect sprays, personal care products are also a source of pollutants. Many construction materials, carpets, wood products and plastics give off pollutants as well. During construction or remodeling activities, many types of dust are produced and find their way into the duct work. If the duct components were stored outside prior to construction, they may have collected dust, rain water and even mold before they were installed in a system.

This can depend on a lot of factors, such as the size of the home, the number of supply ducts, how long since the ducts were cleaned, etc. The whole system should be cleaned and a more efficient filter installed to keep the system clean longer. A competent duct cleaning company would not be able to do this for less than $200 for a small home or $800 for a large home.