How often should Air Duct systems be cleaned?

Frequency of cleaning depends on several factors, not the least of which is the preference of the home owner. Some of the things that may lead a home owner to consider more frequent cleaning include:
 
• Smokers in the household.
• Pets that shed high amounts of hair and dander.
• Water contamination or damage to the home or HVAC system.
• Residents with allergies or asthma who might benefit from a reduction in the amount of indoor air pollutants in the home’s HVAC system.
• After home renovations or remodeling.
• Prior to occupancy of a new home.