Lighting Controls

Installing efficient lighting controls is one of the simplest ways to reduce lighting energy costs. Indoor lights are frequently left on in daytime or when no one is in a room, and rooms are often over-illuminated. In many homes, outdoor area or security lights account for a large portion of overall lighting energy costs, and are often left on when not needed. Even energy-efficient lamps waste energy when left on unnecessarily. Each hour that an unneeded light operates represents unnecessary expense. The controls described below can help minimize unnecessary use of lighting.


Dimming lights can save energy while also extending lamp life. Studies have shown that dimming lights only 10%, a barely noticeable difference in light level, can save 10% of the energy and almost double the life of the lamp. Dimmer switches can be installed in place of a standard on/off switch, and plug-in modules are available for individual lamp fixtures. Note that not compact fluorescents can be used with dimmers - be sure to look for dimmable ones.

Timers and Automatic Switches

Timers are useful for intermittent use areas where people often forget to turn off the light when leaving. They can be preset to the desired time delay or manually set for a specific length of time. Some are capable of controlling two devices, like a bathroom light and exhaust fan.

Automatic switches can be set to turn lights on and off when a door is opened or closed - these are ideal for closets and storage areas.

Occupancy Sensors

Occupancy sensors (also called vacancy sensors) can help ensure that rooms are not lit unnecessarily. They use either passive infrared or ultrasonic technology to sense whether a room is occupied, and automatically turn off the lights when the occupant leaves the room. Some have built in light sensors so the lights won't come on in the daytime.

Passive infrared sensors detect body heat, so in order to work properly, they need to be located where they have an unobstructed "view" of the room.

Ultrasonic sensors emit an inaudible sound pattern that is disrupted by movement. They are best suited for spaces where occupants may be out of the sensor's line-of-sight. Ultrasonic sensors are sensitive to air movement and should not be placed near heating or cooling registers. Dual-technology sensors use a combination of passive infrared and ultrasonic technologies to reduce the risk of false triggering (lights coming on when the space is unoccupied).

Motion Sensors

Motion sensors are a good choice for outdoor security lighting. A motion sensor turns the lights on only when movement is detected. Once any movement has stopped (delay time is adjustable), the detector switches the lights off.


Photocells sense existing light and turn lights on when natural light levels are low and off when light levels are higher. They can be useful for controlling outdoor landscape or decorative lighting, allowing the outdoor lighting system to adjust to changing seasons. If lighting is needed for only a portion of the night, a photocell can be used to turn lights on and a timer to turn them off. With area or security lighting, they can prevent the lights from being left on in the daytime. Some have delay mechanisms to prevent temporary cloud cover from turning the lights on.

Remember that in terms of energy efficiency, the main benefit of a photocell is its ability to turn the light off when not needed. Photocells that turn on lights whenever it's dark can waste energy. For best results, combine them with motion sensors so the light is only on when needed.

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