How Often Should You Have Your Air Ducts Cleaned?

Research has also demonstrated that having your HVAC system cleaned can allow it to run more efficiently by removing debris from sensitive mechanical components.  Clean, efficient systems are less likely to break down, have a longer life span, and generally operate more efficiently than dirty systems.
How often you have your air ducts cleaned depends on several factors, which includes your personal preference.  Some of the things that may lead a home owner to consider more frequent cleaning are:
Smokers in the householdPets that shed a lotWater contamination from a flood, or excessive moisture from condensationIf you have allergies or asthma and would benefit from a reduction in the amount of indoor pollutants in your home’s HVAC systemAfter home renovations or remodelingPrior to moving to a new homeIf there is substantial visible mold growth in your ductsIf your ducts have been infested with mice or insectsOr if your ducts are clogged with excessive amounts of dust and debris, and particles are actually being released into the home from your registers.
Source: www.nadca.com/consumerinformation/residentialconsumer.aspx, and www.epa.gov