Most people do not know that the air quality in their houses has been compromised. For a central air system, the air in the building is circulated into the ducts repeatedly. The air will suck up toxins that will make it less safe to breathe if the ducts are not clean. The dust and debris inside the ducts are extracted with air duct cleaning.
While a homeowner should frequently vacuum their registers and clean their filters, there is a lot of dirt and debris build-up through the duct system years. It is recommended that homeowners disinfect their duct systems every three or five years.