"Treat the Earth well. It was not given to you by your parents; it was loaned to you by your children." Native American proverb
February 26, 2011
Shedding some light on energy efficient lighting
Or "Lighting 101 for Dummies"
Look at shoppers’ faces as they stand in front of the lightbulb shelves in any store, and you’ll see some perplexed looks. Whether installing outdoor lighting or replacing indoor bulbs, there is a lot of confusion among consumers about the newer bulbs now available. And perhaps even anger and angst.
Did the government outlaw incandescent light bulbs? No. The 2007 Energy Independence and Security Act did not outlaw incandescents. Instead, it set efficiency standards that incandescents cannot meet. The law requires that all general-purpose light bulbs that produce 310–2600 lumens of light (more on that later) must be 30 percent more energy efficient than current incandescent bulbs by 2014, beginning with 100-watt bulbs in 2012. The new standard applies to clear, frosted, soft white, and daylight bulbs; specialty colors and shapes are not. It does not affect the existing supply of incandescent bulbs in retail stores or on your top shelf at home. Feel free to use them up if you don’t mind wasting energy.
When do the new efficiency standards go into effect? Under the legislation, 100-watt incandescent bulbs will be replaced starting Jan. 1, 2012, followed by 75-watt bulbs in 2013, then 40-watt and 60-watt bulbs in 2014.
In the average U.S. home, lighting accounts for about 20 percent of the electric bill. A high-quality CFL will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75 percent less energy and lasts about 10 times longer than an incandescent bulb. Nationwide, the energy savings potential is significant. According to the U.S. government's ENERGY START program, if every U.S. home replaced just one incandescent bulb with an ENERGY STAR qualified bulb, enough energy would be saved to light more than 3 million homes for a year and reduce energy costs by $600 million.
Will the new standards reduce light pollution? More energy efficient lighting will reduce the wasted energy cost of $2 billion in the U.S., but unshielded up-lighting--most from poorly designed street lights—will still illuminate the sky. Currently, two-thirds of Americans cannot see the Milky Way from their backyards. Homeowners should consider this when adding up-lighting in their backyard landscaping.
How does a Compact Fluorescent Lightbulb (CFL) work? The argon and mercury vapors inside the twisted tube of a CFL get very excited in the presence of an electric current, producing invisible ultraviolet light as the mercury turns into a gas. That makes the phosphor coating inside the bulb glow—without much heat by the way. It takes a few seconds for all this excitement to occur. So be patient as the bulb gradually brightens. On the other hand, the electric current inside an incandescent bulb heats a thin tungsten filament to the point that it glows, but the bulb loses about 75 percent of its energy in the form of heat.
Why do CFLs cost more? At the moment, CFLs are more costly because they include a ballast (or resistance) at the base of the bulb to regulate the current. Think back to the original cost of DVD players and computers. You can expect a drop in efficient light bulb costs during the next few years as well. Consumers should factor in the lower energy cost and much longer lifespan of CFLs that offset the higher initial cost of CFLs. The latest packaging for CFLs includes an estimated saving that’s quite impressive. The bottom line is that CFLs and LEDs last longer and they will continue to get better, more efficient, safer and less expensive.
What are lumens? You really need to understand lumens to shop intelligently when replacing your incandescent bulbs. Lumens—not watts—tell you whether a bulb will be bright enough to meet your needs. More lumens mean a brighter light. A CFL and an incandescent bulb with the same lumen rating will produce the same amount of light. Just remember that one dinner candle provides about 12 lumens and that you need about 1600 lumens for reading without eye strain.
We are more familiar with watts which measure the amount of energy used to create that light, and we’ve been wasting a lot of energy to brighten our rooms. Don’t even worry about amps unless you’re an electrician! The color temperatures are usually specified in Kelvins (K). Foot-candles is another term that the average homeowner can leave out of their vocabulary—unless you’re trying out for Jeopardy.
What typical wattage will I need to replace a traditional incandescent bulb? Many folks give CFLs a bad name by not knowing what they’re doing when they try to go green. One Florida resort where I recently stayed replaced their 150 watt incandescents with 8 watt CFLs; reading was next to impossible with them.
When choosing compact fluorescents, always look for bulbs that are ENERGY STAR® qualified because they have been tested to meet stringent performance criteria established by the U.S. Department of Energy and the EPA.
Beginning in mid-2011, new labels will be required on light bulbs to help us get used to thinking in lumens, not watts. In the meanwhile, use this approximate conversion chart when replacing light bulbs.
Is light from a CFL similar to an incandescent bulb? While the first generation of CFLs had a characteristic blue tint, newer designs from reputable manufacturers recreate the warm glow of incandescent bulbs. GE’s “Reveal” CFL brand is supposedly great for reading.
Bulb color temperature is rated in Kelvins. Confusingly, higher Kelvin temperatures are what we consider cool and lower color temperatures are considered warm. CFLs on the low end of the Kelvin scale emit a warmer, yellowish light, like a conventional incandescent bulb. CFLs with higher Kelvin numbers emit a bluer light, like conventional fluorescent lights. To maintain consistent light quality, it’s best to use only bulbs with the same color temperature in a single room.
Quick guidelines: Soft White: 2500-3000 K; Warm, yellowish light; ideal for living rooms, dens and bedrooms Bright White: 3500-4100 K; Crisp, white light; ideal for kitchens and work areas Daylight: 5000-6500 K; Similar to natural sunlight; ideal for reading and detail-oriented work
Color rendition is generally considered to be a more important lighting quality than color temperature. Soou might see “Color Rendering Index” (CRI) on packaging soon to help you compare it with natural sunlight and how colors appear. The top value of the CRI scale (100) is based on illumination by a 100-watt incandescent light bulb. Good quality CFLs have a CRI value between 80-85 which is appropriate for home use. It’s similar to the quality of light used in stores. So check out the labels for “color” of the light that’s produced.
Do CFLs still need to warm up? The first CFLs flickered when they were turned on because it took a few seconds for the ballast to produce enough electricity to excite the gas inside the bulb. Thanks to refined technology, there is now no significant flicker (less than 1 second). However, these bulbs do require a short warm-up period before they reach full brightness, which is why they may appear dim when first turned on. Compact fluorescent bulbs are best used in fixtures that are left on for longer periods of time, rather than in fixtures that are turned off and on frequently.
Do dimmable CFLs exist? Yes, and 3-way settings as well. They are a relatively new line, so read the packaging carefully. Dimmable CFLs typically dim down to about 20% of total light output. Below that, the bulb switches off. If you want to use a CFL with a dimmer switch, make sure you choose a bulb with “dimmable” on the packaging.
What is a Light-Emitting Diode (LED) bulb? Put simply, LEDs emit light by the movement of electrons in a semiconductor material that converts electricity directly into light. They produce less heat than CFLs and last even longer, so are even more energy efficient; they contain no mercury. In contrast to an incandescent bulb, which produces a continuous spectrum of light, the LED emits light of a particular color or wavelength depending on the material used at the base of the chip. Light quality is good as well. They offer a great potential for the future of lighting, but they are still more expensive than CFLs.
What about halogen bulbs? Think of them as a hybrid or a good compromise. They are incandescent bulbs that use gases to improve efficiency. Most halogens achieve the required energy efficiency. Energy saving is approximately 25 percent, compared to 75-80 percent for CFLs.
Finally, what the heck is an ESL bulb? One of the latest bulbs on the block (actually only on the internet) is the "electron stimulated luminescence" bulb, and it contains NO mercury. This mouthful (otherwise known as a Vu1--or Vu one) is UL-certified and recalls the old TV technology of cathode tubes. It seems that a cathode can generate and spray electrons onto a bulb's interior phorphor coating too and make it glow. ESLs have efficiency efficiency and cost somewhere in the middle between CFLs and LEDs. They are dimmable too. Check them out at http://www.vu1corporation.com/ .
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