Duct cleaning has never been shown to actually prevent health problems. Neither do studies conclusively demonstrate that particle (e.g., dust) levels in homes increase because of dirty air ducts. This is because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space.

The best times to have your ducts cleaned is either in the spring or in the early fall, after you have stopped using your HVAC system to cool or heat your property and before you need to start using it again. You have likely experienced that dusty or musty smell when turning on your HVAC system.

Just like any other HVAC system, air ducts require regular maintenance to ensure maximum efficiency. As a general rule of thumb, the National Air Duct Cleaners Association (NADCA) recommends air duct cleaning every 3 to 5 years. With certain methods, that cleaning recommendation can be extended to 6 to 8 years.

The Agitation and Extraction Method This is considered to be the most common and recommended type of cleaning. This method involves mechanical agitation and extraction. Your air ducts will be shaken or agitated by a machine to loosen the dust and debris sticking in the ducts.