|Choosing Energy-Efficient Lighting: CFLs, LEDs and Solar|
|Wednesday, 16 November 2011 00:00 | Written by Alison Pruitt | Article|
If you’re like a lot of people, you want environmentally friendly lighting, but you’re not sure what kind to choose. If you’re looking for something beyond the traditional, energy-inefficient incandescent bulb, these days you have a wide range of choices, including Compact Fluorescent (CFL), Light-Emitting Diode (LED) and solar-powered lights. Although all are better than incandescents, each has its limitations and advantages. Here is a quick guide.
Compact Fluorescent (CFL) Bulbs
CFLs are most cost-effective and efficient in areas where lights are usually turned on for long periods of time, such as overhead or outdoor lights. You will recoup the cost of CFLs more slowly where lights are turned on for short periods, such as in closets and pantries. Because CFLs do not need to be changed frequently, they are ideal for hard-to-reach sockets.
In 2007, Americans saved $1.5 billion by switching to CFLs—enough energy to light all the households in Washington, DC for over 30 years. Furthermore, switching to these bulbs removes as many greenhouse gases as planting nearly three million acres of trees or taking two million cars off the road each year.
One drawback to CFLs is that they contain traces of mercury and consumers need to exercise caution if a CFL bulb is broken.
Light-Emitting Diode (LED) Bulbs
Assuming the average light bulb is on for 10 hours a day, a single 40-watt incandescent will generate 196 pounds of carbon dioxide every year while a 13-watt LED equivalent will be responsible for only 63 pounds. The portion of a building’s carbon footprint that comes from lighting can be reduced by 68% when changing all incandescent bulbs to new LEDs. At the end of a 20-year period, LEDs could save the country approximately 3.75 quads of energy annually, or the equivalent annual output of forty 1000-MW power plants. LED lights’ longer lifespans also mean less landfill waste.
Despite a higher purchase price, LED light bulbs can be a cost-effective option for lighting a home or office space because they last so much longer. The US Department of Energy tests LED lights for energy efficiency and performance, and attempts to educate consumers about the benefits of choosing lighting fixtures based on costs over the life of the device rather than initial purchase price.
And the prices are poised to come down. In 2008, a research team at Purdue University produced an LED bulb with lower production costs. They predict that their new LED technology will be competitively priced with CFLs in a few years.
LED lighting has recently become popular in outdoor lighting because of its durability and weather resistance. Wal-Mart recently unveiled its first LED parking-lot lights at its Leavenworth Kansas store and numerous municipalities use LEDs as efficient and reliable street lights.
Because of easy access to sunlight, solar lights are primarily used outside as walkway or garden lights. Outdoor solar lights range from glowing pathway markers to pole-mounted patio and high-beam security lights. They are easy to install and virtually maintenance free. But a solar lighting system will work well only if the solar cells receive the necessary hours of sunlight. Therefore, homeowners need to consider climate and the specifics of their property when choosing solar lights.
Nightly lighting times vary depending on how clear the sky is on any given day. Most lamps stay lit an average of eight to ten hours, but lights that receive less sunlight than the solar cells require will operate for fewer hours per night than expected. During the winter, lighting times may vary as much as 30%–50%. Insufficient battery charging will not only affect performance, it also may reduce the life of the battery.
The good news is that solar lighting systems can be designed for a wide variety of conditions. Some are self-contained units, but others have the lights separate from a solar-cell panel. Therefore, only the panel needs to be placed in a sunny location.
A consumer looking for energy-efficient lighting solutions has a number of options to choose from—and may want to use different kinds of lighting in different areas of the home. We hope the above guide will help you choose widely—for your benefit and the Earth's.
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