The cold air return(s) is an integral part of the home ventilation system. It is, therefore, easily identified by its large vent size and proximity to the furnace. Often there is more than one cold air return in a home. The cold air return draws air from the home into the furnace. Unfortunately, it also draws in all the common debris present in homes such as carpet fiber, dust, pet hair, etc. Since the cold air return vent is the gateway to most debris and contaminants, cleaning it is an important part of the air duct cleaning. There are different methods for cleaning air ducts.