LED light bulbs contain no mercury, and they offer other advantages over compact fluorescent light bulbs. LED light bulbs turn on instantly, last much longer and are more energy efficient. Their lifetime isn't affected by frequent cycling on and off, so they're especially suitable for light fixtures that don't stay on very long -- or conversely, for light fixtures that stay on so long that the extra energy efficiency is significant. LED light bulbs are also less apt to break.
Reviews say that in the long run, the extremely high cost ($20 to $80) of big screw-in LED light bulbs will pay for itself in savings on electricity. However, we were unable to find any compelling evidence that the rated life holds true for every bulb. It's one thing to gamble on a compact fluorescent light bulb that costs $2 to $4, yet another to wonder if an $80 light bulb will last its rated life -- especially because light bulb ratings are based on ideal conditions of temperature and humidity.
Until recently, LED light bulbs designed to cast light in all directions (for use in a regular table lamp) didn't put out enough lumens to make this realistic except for dim "atmospheric" background lighting. Some owners say the light from an LED is too cold and bluish. Owners say they're dimmer than expected, even when used in a light fixture that takes advantage of their directional beam (usually a 60- to 100-degree angle). Manufacturers are making efforts to produce LED lights that are both affordable and offer light equivalent to that produced by incandescent light bulbs, and a few have cropped up that receive positive reviews. Prices have begun to come down, also, making LEDs an up-and-coming contender for standard household use.
The least expensive LED light bulb at present for everyday use is the EcoSmart LED A19 (*Est. $20), a 40-watt equivalent light bulb that's sold exclusively at Home Depot. We've seen no professional reviews for it, but around 30 owners post at HomeDepot.com and give it a solid rating overall. Most are completely pleased, but some drawbacks are noted. We saw comments that the EcoSmart LED A19 is prone to throwing off radio-frequency interference, which can cause static on nearby radios. One complains that the bulb burned out in its first month of use. Another says the bulb is somewhat directional.
GreenOptions.com, an environmentally focused social network that allows consumers to rate and review environmentally friendly products, also offers a selection of reviews for LED light bulbs, but the volume of reviews is slim. Still, the EarthLED DesignoLux CL-3 LED (*Est. $30) light bulb earns the top ranking among all types of light bulbs reviewed on the website, with an average rating of 4.5 stars out of 5, based on more than 10 owner-written reviews. Owners say the EarthLED DesignoLux CL-3 looks like a regular light bulb and produces enough soft, warm light -- using just 3 watts to replace 30 watts -- that it's indistinguishable from an incandescent. The EarthLED DesignoLux CL-3 is rated to last for 50,000 hours, and EarthLED offers a three-year replacement warranty. Several owners do note that the DesignoLux CL-3 is most appropriate for smaller spaces, such as bathrooms, that don't require a lot of light.
EarthLED also produces the EvoLux and ZetaLux models, which have multiple LEDs in a single casing. The EvoLux (*Est. $50) claims to deliver light equal to that of a 100-watt incandescent, while the ZetaLux (*Est. $40) claims to be equivalent to a 50- or 60-watt incandescent. The ZetaLux is rated for 50,000 hours. The EvoLux has fewer than 10 owner-written reviews on GreenOptions.com, but does maintain a rating of 4 stars out of 5, earning the sixth position in the website's overall light bulb rankings. Several owners say the brightness of the EvoLux is comparable to light produced by equivalent CFLs, but the light is very directionally focused. The ZetaLux has even less feedback, but what's there is mostly positive, earning this bulb an overall rating of 4.5 stars out of 5. Owners say the light quality is fine and the instant-on is a plus over CFLs, but like the EvoLux the light focuses in one direction.
Several companies have recently announced LED light bulbs that aim to overcome the directional limitation of current LED bulbs, which perhaps will move them further into the mainstream. For example, the GE Energy Smart LED bulb is an omnidirectional 9-watt LED that produces light equivalent to a 40-watt incandescent. The GE Energy Smart LED, to be released in late 2010 or early 2011, has a plastic casing surrounding the bulb that looks like a series of fins, designed to help cast light all around the bulb instead of in one direction, as most current LEDs do. The GE Energy Smart LED has a life span rating of 25,000 hours. Osram Sylvania and Philips have announced 60-watt equivalent LED bulbs that are scheduled to be available by the end of this year or early 2011.