Sensors Mag

The Lights Are Out, But Everyone Is Home

November 16, 2006 By: Tom Kevan

E-mail Tom Kevan

Our culture is full of conspiracy theories, involving the Kennedy assassination, extraterrestrials, and RFID. We all take these with a grain of salt because we are aware that only kooks place any stock in them. But there is one that I fervently believe: Both my wife and daughter are agents of the New Hampshire power company. Their job is to keep as many lights on in the house as possible. Until now, only I prevented them from running up a massive electric bill every month. But that's all changed.

Sensors to the Rescue

I was looking over press releases announcing new sensor products when I found a new ally. Watt Stopper/Legrand, a manufacturer of energy-efficient lighting controls, has released a family of vacancy and occupancy sensors designed for the home. The new Watt Stopper sensors give homeowners a simple way to save energy by automatically turning lights off in empty rooms.

The sensors replace wall switches in rooms and hallways and use passive infrared technology to detect occupancy. Two types of sensors approach the problem differently, but achieve the same result. With vacancy sensors, you press the button to turn lights on; with occupancy sensors, the lights turn on automatically when someone enters the room. After the room is vacant, the lights automatically turn off. You no longer have to run around the house turning lights off.


This level of home automation through the use of sensors is still relatively new. As a result, these devices don't come cheap, with a price range of $29 to $40. If you focus on the long view, though, the cost is worth it. The Partnership for Home Energy Efficiency (DOE, HUD, EPA) estimates that by 2015 use of electricity for lighting will grow 30%, with a comparable rise in utility bills. The deployment of vacancy and occupancy sensors promises to end the typical pattern of hours of wasted energy.

Watt Stopper/Legrand's sensors comply with energy codes such as California's Title 24-2005, which mandates that lighting in homes be highly efficient or controlled by a vacancy sensor or a dimmer. These new devices also promise to make home lighting more "green." Every time a traditional light switch is replaced by one of these sensors, the CO2 emitted into the environment is reduced. "If 100 million U.S. households were to control one 60 W bulb with one vacancy sensor, this would represent almost a half billion kwh in energy savings and a reduction of almost one billion pounds of CO2," claims the company.

If you have any stories or comments on new sensor technology that has tickled your fancy or conspiracy theories that have captured your imagination, let us know. Scroll down to the bottom of the page and post a comment!

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