Green Glossary: Motion Sensor Lighting

Motion sensors automatically turn lights on when they are needed (read: when motion is detected) and turn them off a short while later.

"Motion sensors are best used in areas of the house that get little foot traffic," writes Planet Green's Josh Peterson. For example: The garage, the bathroom, the stairwell, the porch, the front door, basement, the attic, and the laundry room. Peterson explains: "When a person enters one of these rooms, the motion sensor will catch their movement and switch on the light. When the person leaves, the light will go out after a set period of time. This ensures that lights, like the basement light, do not get left on needlessly for hours or even days."

Since motion sensors use electricity and sometimes require batteries, they're best for those who just can't seem to turn off lights. A more contentious person might want to look into an energy efficient bulb with a motion sensor built in. Yes, such a thing exists. The MotionBulb "turns on automatically when you enter the room and turns off automatically when you leave" and the CFL bulb only uses 20 watts while emitting the equivalent of 75 watts of light.