Abstract: 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.