Green Homes Special Series: Part Four: Lighting

Solid-state lighting such as Light Emitting Diodes or LEDs. According to the Lighting Research Center’s program manager and adjunct professor Patricia Rizzo, MSc, LEDs are semiconductors—materials that fall between those able to conduct (like metals) or insulate (like wood and rubber) electricity—and they have remarkable properties. They can act as conductors or as insulators; work at room temperature, at low voltage or with direct current; and can turn on and off almost instantly. While LEDs share all these characteristics with other semiconductors, Rizzo says, the difference is that, based on the materials used to make the semiconducting “crystal,” a byproduct is light. Among LED benefits are a long life of 50,000 hours or more, low voltage and durability. Among their downsides are high initial cost and not being available for all general lighting needs. The Department of Energy’s new Energy Star specifications for solid state lighting luminaires are expected to go into effect September 30, 2008. Here are some quick tips to remember about eco-friendly lighting in your home: If you use CFLs, check now with your local government to find out how to dispose of a bulb in case it breaks. According to the EPA, here are your initial steps. If a CFL breaks, a small amount of mercury escapes. Open a window and leave the room for 15 minutes or more. Do not use bare hands to pick it up; use disposable rubber gloves. If the bulb broke onto on a flat surface, scoop up fragments and powder with stiff paper and place them in a plastic bag. Wipe the area clean with damp paper towels or disposable wet wipes and place them in the plastic bag. Seal the bag. If a CFL breaks on a carpet, remove as much material as you can using sticky tape. Once all visible material is removed, vacuum the area, remove the vacuum bag and put the bag and the sticky tape debris in a plastic bag and seal it. In both instances, place the first sealed bag in a second plastic bag and seal that bag. Dispose of the bags according to your community’s local disposal rules. Since energy use for lighting homes is only around 10 percent, says Jay Hall, acting director for LEED for Homes, changing out many or all of a home’s incandescent bulbs may not make a huge impact for an individual—perhaps $100 a year—but it will make an impact in the larger picture. According to the Department of Energy, if every American home replaced just one light bulb with an Energy Star--qualified bulb, the effort would save enough energy to light more than 3 million homes for a year and more than $600 million in annual energy costs as well as prevent greenhouse gases equivalent to the emissions of more than 800,000 cars. In checking for light output equivalency, compare lumens. If a 60-watt incandescent produces 800 lumens and a qualified CFL, at 13-15 watts, produces 800 lumens, you are getting similar light output but with differing amounts of power needed to produce that amount. In the 2008 call for entries in the Lighting for Tomorrow competition—organized by the American Lighting Association, U.S. Dept. of Energy and Consortium for Energy Efficiency—a category has been added to highlight ongoing progress in LED device innovations. The 2007 solid-state grand prize winner was LR6, a product of LED Lighting Fixtures (LLF) Inc. of Morrisville, N.C. LR6 is a complete recessed downlight trim kit and LED light engine in one unit that fits standard recessed housings in new construction or as retrofit for existing fixtures. The contest description notes that “the light output and color quality are very similar to incandescent reflector lamps typically used in residential downlights for less than one-fifth the wattage. The product exceeds the luminaire efficacy of even the most efficient fluorescent downlight systems.” LLF’s vice president of sales and marketing Mike Fallon sees CFLs as “a stepping stone to solid-state lighting.” The LR6, for example, uses less than half the energy of a comparable fluorescent and 85 percent less energy than a conventional incandescent and contains no mercury. Improved Lighting Efficiency LRC’s Rizzo and her colleague Jean Paul Freyssinier-Nova, M.S., lighting research specialist and research assistant professor, say there are several ways to improve home lighting efficiency. Among them: Use CFLs where appropriate, such as table and floor lamps. Select CCTs, correlated color temperatures in the 2700 to 3500K range, depending on preference for how warm or cool light source should appear. Indirect lighting such as linear fluorescents will maximize room surfaces as extensions of light source, soften shadows, reduce glare and create impressions of brighter spaces. It’s also a good technique to conceal light sources so just the effect of the light is appreciated. Dimmers on all incandescents will increase their life significantly and create atmosphere. Use occupancy, or vacancy, sensors wherever they make sense, such as in kids’ bedrooms, laundry rooms, bathrooms, closets, basements and garages. Rizzo said the LRC has been cautious in recommending LED products up until now, but there are better products hitting the market. “In the area of downlights, undercabinet lights and cove lighting, we can safely say that certain LED products perform well and are becoming easier to install,” she says. “Heat sinks are integrated into the fixture design, and they can be plugged in or hardwired to run on 120 volts rather than requiring a driver to run on 12 volts.” She suggests viewing products to determine light warmth or coolness. So, what light to choose? Each light source has its own characteristics and serves a specific function. “We still use the candle for mood and atmosphere,” says Rizzo. “The incandescent has been with us since 1879. It’s still the most familiar and the least expensive to purchase and, in some cases, it could be the most efficient depending on its application. Lumens per watt is not always the absolute metric that should be used to measure a light source's efficacy—how you use it should be,” says Rizzo. “For example, if you want to accent a piece of artwork, you will not do well with a CFL. It has no center beam punch, no filament, so you will just get a diffuse wash of light—no dramatic effect. Every source has its place in our lives.” Read other Green Homes Special Series articles here.

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