Fans, blowers, pumps, air conditioners, heaters, and compressors all employ AC motors in the HVAC industry. Roof ventilators and air circulators use direct drive blower and belt drive HVAC AC motors to circulate air. Water circulator AC motors supply power to hot water circulation pumps, while room air conditioner AC motors circulate cool air created by room air conditioners. Fans that circulate heat out of the heater and into the room are powered by unit heater AC motors. In gas furnace applications, draft booster AC motors are employed to sweep out any leftover combustion fumes, while transformer cooling fan AC motors operate fans that cool electrical transformers.