Air cleaner including a case having an inlet and an outlet, a fan inside of the case, for drawing air through the inlet and discharging the air through the outlet, a filter assembly inside of the case for cleaning the air drawn into the case through the inlet, a heat exchanger inside of the case for heating or cooling the air drawn into the case, selectively, and a plurality of fins between the fan and the outlet for guiding the air drawn into the case to the outlet, thereby ventilating the room.