An exhaust system for exhausting air from appliances in a commercial kitchen is described. The exhaust system comprises an exhaust fan that includes a housing, a motor mounted in the housing, and a fan directly driven by the motor. A motor compartment surrounds the motor. Cooling air is induced into and through the housing and directed into the motor compartment for cooling the motor. Cooling air is discharged from a motor compartment and mixed with exhaust air to form an air mixture that is directed through the housing of the exhaust fan.