a compact , self - contained cooling - heating - humidifying - filtering apparatus has an endless band of water - absorbent , air - permeable material traveling in partial immersion in water contained in a receptacle within a conditioner housing . a fan produces a continuous airstream from an air inlet to an air outlet , both defined in the housing , through the endless band . a damper is provided in order to divide the air outlet into a cool air outlet and a warm air outlet . the damper is operated by a hand lever so as to selectively communicate the cool and warm air outlets with the air inlet . an electric heater is disposed at the warm air outlet or , preferably , on one of the opposite surfaces of the damper for heating the air flowing through the warm air outlet . this location of the heater serves to assure noiseless cooling operation and to permit the heater to heat effectively , despite its limited capacity , the air flowing through the warm air outlet .