Energy-efficient Lighting Comes of Ageby Jim Motavalli
E Magazine, October 31, 2003
Americans spend about one-quarter of our electricity budget on lighting, yet we're surprisingly ignorant about the basic properties of the lightbulb, let alone the recent innovations in energy-saving lighting design that can cut consumer costs 30 to 60 percent a year. Quick, how many lumens in a 100-watt bulb? If you answered 1,750, you're among the lighting elite.
Some vital terminology: Lumens are a measure of light output. The watt is a measure of electric power dissipated or consumed. Footcandles are measurements of light distribution on a horizontal surface. According to the Illuminating Engineering Society, a measure of 30 to 50 footcandles is adequate for most home or office work, allowing comfortable illumination without eye strain. For close work — sewing, reading fine print — you may need 200 to 500 footcandles.
The most common types of household lighting are incandescent and fluorescent. The incandescent light, dating back to Thomas Edison, is the least expensive and most common, but it also has a short lifespan and is expensive to operate. Tungsten halogen lights are more energy efficient than ordinary incandescents but are also costly to use and present safety issues. Fluorescent lights are three to four times more efficient than incandescent bulbs, but their harsher glow has traditionally relegated them to commercial or office settings.
The compact fluorescent bulb (CFL) has revolutionized people's perceptions of fluorescent light by moving away from awkward tube fixtures and glare-prone light. If every American household switched from incandescents to CFLs, it would cut power demand for lighting in half. A 15-watt CFL bulb yields as much light as a 75-watt incandescent. CFL bulbs certified by the federal Energy Star program (and guaranteed for a year) are made by GE, Panasonic, Osram, Sylvania, Philips, MaxLite, and SunPark. CFL bulbs contain small amounts of mercury, so it's important they be recycled properly.
Today's CFLs are much improved over earlier models (they even work with dimmer switches) and can be screwed into most household fixtures. The cost differential between CFLs and conventional bulbs (while still substantial) is steadily shrinking. A CFL can replace an incandescent bulb with up to four times its wattage, resulting in a 75 energy percent savings. Although a CFL bulb may cost $10 and an incandescent bulb only 75 cents, consumers who leave their lights on for four hours a day will realize a $5.85 savings after the second year, reports the American Council for an Energy-Efficient Economy (ACEEE). One 18-watt CFL bulb will replace 10 75-watt incandescents and save $45 in electricity costs over its lifetime.
Trouble with Torchieres
"The first thing to do is to get rid of your halogen torchieres," said Jennifer Thorne, an ACEEE research associate. "There are retrofit kits that allow them to use CFL or incandescent bulbs, but it's better to just replace them."
The U.S. Consumer Product Safety Commission issued a warning to consumers in 1996 that the tubular light bulbs in most torchiere-style halogen lamps "can reach very high temperatures [1,000 degrees Fahrenheit] and could start a fire if they come in contact with curtains, clothes, or other flammable material." The lamps are cheap to buy (often only $15) but can use as much as $15 a year in electricity, compared to only a few dollars annually for the less widely available CFL torchiere. Halogen bulbs are also costly and difficult to replace.
Lawrence Berkeley National Laboratories developed a demonstration CFL torchiere that consumed 67 watts compared to the halogen unit's 270 and gave off 50 percent more light. You can't buy it, but you should be able to find a Verilux Happy Eyes floor lamp (around $120), which uses a 27-watt linear CFL bulb (with an expected life of 5,000 hours) to equal the light output of a 100- to 125-watt incandescent bulb. Pennsylvania-based Emess Designs makes a similarly priced torchiere sold at Home Depot and Lowe's stores that produces an impressive 4,041 lumens while consuming only 65 watts of energy. Many local utilities provide catalogs offering subsidized low-cost CFL lights to consumers.
Is it really possible to buy attractive outdoor lights powered only by the sun? Yes, indeed, though there are a few drawbacks. The Solite pagoda-style four-watt fluorescent light (approximately $60) uses a solar cell and a NiCad battery; it switches on automatically to produce up to six hours of light each night. Similar products are made by Alpan (formerly Siemens), Soltek, Brinkmann, and SolarTech. Solar lights of this type are not bright enough for major outdoor illumination, but they're great for accent lighting. With the Solite unit, both battery and bulb will have to be replaced after about a year of use.
Another way to capture the sun's energy is with high-tech skylights such as the Solatube and Sun Tunnel Skylight, which trap light and channel it down through a tube mounted in your roof. The Solatube can be located on one section of your roof and direct its light to another, giving the advantages of a skylight to confined spaces such as bathrooms and hallways. The Solatube also filters out 99 percent of ultraviolet rays, so it will not cause fading.
The Right Stuff
Consumers may well be confused by the technical terminology surrounding lighting. Patricia Rizzo, project manager for the Rensselaer Polytechnic Institute Lighting Research Center, warns consumers to do their homework and check packaging before buying a CFL or other energy-efficient light.
"If they get it home and the color temperature (measured in Kelvin units) is too low, they may hate the light it produces," she said. "In general, lower color temperature produces warmer light."
Placement of lights to diminish harsh shadows is also important, Rizzo said. Thorne added that consumers will also save considerable energy by installing occupancy detectors to turn off lights in vacant rooms.
Rizzo was the lighting consultant for a 4,000-square-foot, energy-efficient demonstration home in Saratoga Springs, N.Y. The home's inviting lighting (mostly CFLs with some halogens and linear fluorescents) has won rave reviews, but it costs the owners only $90 a year compared to $290 a year for traditional lighting.
Rizzo said she wants to retrofit her own home, but "I can't get an electrician to listen to me."
The federal Energy Star guide to home appliances www.energystar.gov
Energy Federation Incorporated www.efi.org/products/lighting/veri0002.html
Emess Designs lamps: (724) 758-0707
Zero Waste Alliance www.zerowaste.org
Sun Tunnel Skylight www.advancedenergyonline.com/catalog
Solar garden lights www.comforthouse.com/comfort/solarlights2.html
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