"Exhaust Fan" two-way flow of new fans with independent air supply and exhaust systems, contaminated air through the exhaust port, exhaust pipes and exhaust products discharged to the outdoors, fresh outdoor air through the blower and air duct outlet into the room. Such products and exhaust blower placed with a housing, fan work, fresh air and exhaust air fed simultaneously through a heat exchanger fan cabinets, with heat exchangers, exhaust air and fed fresh air will heat exchange, energy recovery.