Dear EarthTalk: What’s the story with LED light bulbs that are reputed to be even more energy-efficient than compact fluorescents?

-- Toby Eskridge, Little Rock, AR



Perhaps the ultimate “alternative to the alternative,” the LED (light-emitting diode) light bulb may well dethrone the compact fluorescent (CFL) as king of the green lighting choices. But it has a way to go yet in terms of both affordability and brightness.



LEDs have been used widely for decades in other applications—forming the numbers on digital clocks, lighting up watches and cell phones and, when used in clusters, illuminating traffic lights and forming the images on large outdoor television screens. Until recently LED lighting has been impractical to use for most other everyday applications because it is built around costly semiconductor technology. But the price of semiconductor materials has dropped in recent years, opening the door for some exciting changes in energy-efficient, green friendly lighting options.



According to HowStuffWorks.com, LED bulbs are lit solely by the movement of electrons. Unlike incandescents, they have no filament that will burn out; and unlike CFLs, they contain no mercury or other toxic substances. Proponents say LEDs can last some 60 times longer than incandescents and 10 times longer than CFLs. And unlike incandescents, which generate a lot of waste heat, LEDs don’t get especially hot and use a much higher percentage of electricity for directly generating light.



But as with early CFLs, LED bulbs are not known for their brightness. According to a January 2008 article in Science Daily, “Because of their structure and material, much of the light in standard LEDs becomes trapped, reducing the brightness of the light and making them unsuitable as the main lighting source in the home.” LED makers get around this problem in some applications by clustering many small LED bulbs together in a single casing to concentrate the light emitted. But such LED “bulbs” still don’t generate light much brighter than a 35-watt incandescent, much too little light for reading or other focused tasks.



If LEDs are going to replace incandescents and CFLs, manufacturers will have to make them brighter. EarthLED is lighting the way with its EvoLux and ZetaLux bulbs, which use multiple LEDs in a single casing to generate light. The EvoLux delivers light equal to that of a 100-watt incandescent, the company says. But the $80/bulb price tag may be tough to swallow. The ZetaLux, which retails for $49.99, delivers light equivalent to a 50- or 60-watt incandescent, will last 50,000 hours and costs only $2/yearly to run.



Other bulb makers are working on similar designs for high-powered LED bulbs, hoping that an increase in availability will help spur demand, which will in turn lower prices across the board. Until then, consumers can find LED bulbs suitable for secondary and mood lighting purposes in many hardware and big box stores. C. Crane’s 1.3-watt LED bulb, for example, generates as much light as a 15-watt incandescent bulb. Check your local hardware store for other options, as well as online vendors such as Best Home LED Lighting, Bulbster, SuperBrightLEDs.com and We Love LEDs.



CONTACTS: How Stuff Works, www.howstuffworks.com/led.htm; EarthLED, www.earthled.com; Best Home LED Lighting, www.besthomeledlighting.com; Bulbster, www.bulbster.com; SuperBrightLEDs.com, www.superbrightleds.com; We Love LEDs, www.weloveleds.com.



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