Air Duct Cleaning ... what is it?

How do you clean air ducts?  How long does it last?  Why should I have them cleaned?  What are the benefits?  What happens if I don't have them cleaned? 

First of all, let us present two abbreviations that you will see repeatedly within this information.  IAQ =  indoor air quality; HVAC = heating, ventilating, and air conditioning.

What is "duct cleaning"?

Ductwork sometimes can become both the source and the pathway for dirt, dust, and biological contaminants to spread through the building.  In this case, duct cleaning usually means the removal of dirt, slime, mold, debris, and other materials found in ductwork and other HVAC components (e.g., cooling coil, drain pan).

When should duct cleaning be performed?

Supplier schedules HVAC equipment suppliers and manufacturers sometimes provide instructions on when and how "cleaning" should be performed.  Cleaning schedules typically depend on operating schedules, climate, filtration used, air contaminants, costs, and building occupant expectations.