Abstract: The room temperature controller of the present invention is adapted for use in a room in which the temperature is controlled by a thermostat coupled to an air conditioner unit. The room temperature controller includes a detector positioned within the room for detecting from a distance the presence of an occupant within the room. A logic and control circuit is coupled to the output of the detector and to the thermostat. The logic and control circuit modifies the normal operation of the thermostat when an occupant is not detected within the room to reduce unnecessary heating and cooling expenses. This circuit also enables the thermostat to operate normally for timed intervals when an occupant is detected within the room.