Duct cleaning eliminates bacteria and molds which form inside the ducts over a period of time. Once they enter the air conditioned space, they end up polluting the indoor air. Regular duct cleaning ensures that the occupants breathe clean and pollution-free air. complete HVAC system should be cleaned to prevent re-contamination. This is achieved by removing the contaminants all the way from the entry of air to its exit including all internal surfaces of the airstream - air handling units, fans, coils, mixing boxes, variable air volume boxes, heat exchanges, condensate drain pans, ductwork and components in which air travels through or across.