The Best Equipment Our proprietary truck-powered vacuum is 30 to 40 times as powerful as the rotary-brush type vacuums that end up doing more harm than good. This ensures that all foreign materials loosened from the sides of the air ducts are pulled into the filter compartment on the truck.The Most Experience Duct Doctor has been a single-focus Air Duct Cleaner since 1985. Technicians are uniformed and well-trained by NADCA Certified Air System Cleaning Specialists and perform cleaning using the source removal procedures.The Duct Doctor Process The rigid and non-collapsable vacuum hose is inserted into both the return and the supply ductwork. Once all the debris and contaminants have been dislodged and airborne inside the ductwork by the air-driven agitation devices, the powerful vacuum unit will remove it safely outside the home.. Air Duct Cleaning, Dryers