When people are unlikely to remember to turn lights off, an occupancy sensor is a great way to save money. This is an easy to install device that will turn lights on and off automatically in an individual space such as a private office, restroom, or storage area. Sensors are mounted on the wall just like an ordinary light switch, or installed in the ceiling or high on a wall. The sensor turns the lights on when it senses someone coming into the room or area, and then turns the lights off some time after no longer sensing anyone present.
Units come either with fixed, preset time delays and sensitivity levels, or with adjustable ones.
You normally would want to buy a sensor which can be adjusted for both time delay and sensitivity. You will need to carefully consider the time delays needed for the area, and the range, sensitivity, type, and mounting position of the sensor. Heat sensors, on the other hand, must be placed so that no obstruction blocks their sensing field. The more hours the lights are off and the more watts controlled by the sensor, the greater the energy savings. The lodging industry is experiencing success with sensors where not only lights but HVAC, too, may be controlled to keep occupants comfortable but save energy when the room is unoccupied.