National Homebuilder GreenHome Makes Lighting Savings, with ‘Sense’

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Many of the vacancy sensors used in this house are programmed to keep the light fixtures off if enough natural sunlight is available, helping in part to save the homeowners’ energy usage by 50 percent.

How an award-winning green home makes CFL and LED lighting even more energy-efficient through timers and sensors.


Nov. 06, 2009 — by .(JavaScript must be enabled to view this email address)

Everyone knows that CFLs (compact fluorescent lamps) and LED (light emitting diodes) fixtures conserve electricity. CFLs are four times more efficient and last 10 times longer than incandescent bulbs, while LEDs use less than 10 watts of electricity and have even longer lifespans. They’re both great energy-savers, no doubt.

But a 4,000-square-foot green home in Raleigh, N.C., proves that it’s possible to get even more efficiency out of these new lighting technologies.

A variety of different occupancy sensors and timers installed inside the National Homebuilder Mainstream GreenHome by Cherokee ensure the lights run only when they’re absolutely necessary. Supplied by Watt Stopper, the devices help cut energy use in the home by 50 percent. Also contributing are motorized Sivoia QED shades from Lutron Electronics, a green ventilation system from Panasonic and a PowerCost energy energy monitoring device from Blue Line Innovation.

The big energy-savings stars are the Watt Stopper RS-250 vacancy sensors, installed in key areas like the living room, bedrooms, family room, kitchen and hallways. The sensor installs in place of a traditional switch, but combines a detector that monitors for activity in the room. Users turn on the light by tapping the switch; when the sensor detects no movement in the space, it automatically turns off the lights. These are known as vacancy sensors“manual-on” vacancy detectors, says Jennifer Hahn, product line manager. The room doesn’t go dark instantly, though. The sensor can be set to wait anywhere between five and 30 minutes before switching off the lights.

“Automatic-on” occupancy sensors, meanwhile, were installed in closets, a rear-entry area and several staircases. In addition to turning a light off when a space is unoccupied, these sensors are designed to turn the light on automatically whenever somebody enters. To prevent unnecessary and wasteful lighting, an integral light sensor was enabled on several auto-on devices so lights do not turn on when there is sufficient ambient light.

Lastly, digital timers were installed to control several fans and porch lighting. The timers, which also install in place of a standard light switches, allow the homeowners to select the amount of time the lights should stay on: up to 12 hours for the RT-100 model and up to 60 minutes for the RT-50.

Sensors and timers like these have been used in commercial settings for years. As a result, they’ve suffered from very industrial-looking designs. Recently, though, manufacturers have created low-profile designs that are well-suited for installation in homes. If you’ve already replaced some of your incandescent bulbs with CFLs and LEDs, it might be time to step up your energy-savings efforts by installing a few aesthetically friendly switch sensors and timers.


Wall-switch sensors vary in their maximum coverage ranges and areas. Make sure the one you select can cover your space. The sensor also needs a clear and unobstructed view of the coverage area. Windows, glass doors and other transparent barriers will obstruct the sensor’s view and prevent detection, causing the light to turn off even if someone is in the area.

5 Things to know about CFLs and LEDs
1. CFLs contain trace amounts of mercury; LEDs do not.
2. Only some CFLs can be dimmed.
3. LEDs can be dimmed with systems that use proper drivers. Check with manufacturers.
4. High-quality LEDs are available for recessed lighting, from companies like Philips and Cooper Lighting.
5. Many smaller, inexpensive LED lamps can cause RF interference.



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