LED Light Bulbs More Efficient Than CFL’s?

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

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; EarthLED; Best Home LED Lighting; Bulbster; SuperBrightLEDs.com; We Love LEDs.

GOT AN ENVIRONMENTAL QUESTION? Send it to: EarthTalk, c/o E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881 USA; submit it at EarthTalk; or e-mail us. Read past columns at our archives.

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Comments

  1. I mess around with led’s form time to time. They are really efficient (I ran about 30 red 5mm 55000mcd leds for 3 weeks off of 2 d cell batteries. The only time they burn out on me is when I put too much voltage through them.

    There are downsides though. I have a desk lamp I made that uses about 25 quarter million candle power leds. It is a bright as a 100 watt light bulb but only uses 8-10 (hard to calculate) watts. But the 100 watts is only in one direction and is PURE WHITE. Almost like a welding arc bright white – it does annoy the eyes (I have seen soft white, more natural color leds available, but have not had a chance to mess with them.) Also, the fact that wall current is AC means they actually blink on and off 60 times a second and this is almost noticeable like a strobe effect. I could add a capacitor, but that would mess up the RMS (when you rectify 120 VAC, you get higher than 120 VDC (say 135-155 when you add capacitors, you can get even more than that (170VDC)) calculations and I would probably burn out all of the LED’s.

    In short, LED is not ready for everyone, yet. There needs to be one more major change (probably in the packaging of the LED) before they are usable enough for anything but flashlights and floodlights. Also LED’s being cheaper would be nice.

    If you want to mess around a little, check around on eBay for LED’s. You can order them cheap from china. Get a soldering iron, a voltage meter and some batteries (or you can mess with wall current if you are feeling particularly adventurous – just remember it can kill you or start fires)

  2. I reviewed the LR6 now made by Cree a year ago after I saw it at NYC lightfaire. In addition, I have spoke to homeowners who use it. They love it and it is for general illumination. It does not work with every lighting fixture though and comes with a big price tag.

    Anna http://www.green-talk.com

  3. cree and luxeon do have some very powerful led’s. I still find the little 5mm blinding point of light annoying. (though it does make an excelent flashlight) maybe those LED makers need to concentrate on making a bigger bulb that puts out light more evenly instead of tiny tiny lights that put out five million candella.

    Anyway LED isnt a bad choice if you want maximum efficiency,but sometimes the light itself is annoying.

  4. I agree Cree & Luxeon are powerhouses in the LED world. We find Cree are better for white LEDs and Luxeon make great RGB LEDs. The Cree MCE is allowing for commercial grade general use LED lighting extremely viable nowadays due to efficiency & intense effect.

    There are many cheap LED fittings on the market which often do not perform or last as promised. These should be avoided and for commercial installations proven solid state LED products should always be top priority.

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