How often should I have my air ducts cleaned?
This is one question that we are often asked. Once an air system is thoroughly cleaned, it should remain clean for 3 to 4 years if properly maintained and a high-arrestance filter is installed.
A standard disposable filter only stops about 10 percent of the airborne contaminates, allowing 90 percent of the dust in the room to flow back into the air system.
To maintain protection against biological growth, an EPA-registered biocide should be applied every six to 12 months by a qualified duct-cleaning professional.