Industry standards recommend that you have your air ducts inspected every 2 years for cleanliness. By having your air ducts cleaned regularly, you’ll help improve the indoor air quality in your home, and enhance the efficiency of your heating/cooling system, which may reduce energy bills.
A clean air duct system prevents you from contracting diseases that might otherwise be easy pickings. It can also improve the musty smell that is sometime evident with mold growth improving your overall atmosphere. And, finally, it will help decrease the amount of work that the air conditioning system needs to perform, therefore reducing your energy bills and ensuring a longer life for your ducts and air conditioning system.
Answer: Because they get dirty!
In addition to normal accumulations of dust and dirt found in all homes with air ducts, there are several other factors that can increase the need for regular HVAC system cleaning:
Some occupants are more sensitive to these contaminants than others. Allergy and asthma sufferers, as well as young children and the elderly tend to be more susceptible to the types of poor indoor air quality that air duct cleaning can help address.
Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit housing.