Abstract: An air conditioner includes a fan for forcing air through an air path. An endless belt filter travels through a water tank and across the air path to exchange heat with air passing through the belt filter. A heater is provided for selectively heating the water. A moisture collecting filter disposed in the air path downstream of the belt filter removes moisture from the air. Sensors detect the volume and temperature of the water in the tank for actuating either or both of the heater and a warning buzzer. A speaker is mounted in the air conditioner housing and is connectible to a radio. A switching circuit causes radio sound from the speaker to be muted and instead causes the speaker to emit the warning buzzer when the latter is activated by a sensor.