LEDtronics says its $59.95 LED chandelier bulb lasts up to 50,000 hours. (Ledtronics)

Unless you’ve been living in a candlelit cave, you probably know that compact fluorescent light bulbs are far more energy-efficient, and thus far more planet-friendly, than incandescent bulbs. Still, CFLs are far from perfect: They don't dim well, they shatter and, most troubling, they contain mercury, a serious environmental and health hazard.

A more promising lighting solution, many experts believe, is in LEDs (light-emitting diodes). Invented in 1962, LEDs illuminate JumboTrons and traffic lights. They’re probably in your home, too: the tiny bulbs on remote controls, smoke alarms, appliances and pen lights. The reason they’re used in those products? They last a very long time, which is why environmentalists are abuzz now that LED technology is becoming more widely available in screw-in light bulbs. These LED-based bulbs can last three to 10 times as long as CFLs, going 10 to 15 years without being changed.

The advantages don’t stop at efficiency. LEDs work nicely with dimmers, and they're difficult to break. The catch? Because diodes cast light in only one direction, “they're best for spotlight applications like track lighting and recessed ceiling lighting,” says Keith Ware, owner of D.C. emporium Eco-Green Living (1469 Church St. NW, 202-234-7110), which sells LED lights for the home. (Home Depot and a variety of Web sites, including http://www.ledbulbs.com and http://www.superbrightleds.com, also have them.)

Some new versions feature diodes in clusters that direct light at all angles, but these can be pricey. In fact, the biggest downside to LEDs, Ware says, is their cost. Full-size bulbs start at about $20, and those that mimic the brightest incandescents can run over $100.

However, demand and technology are improving to make LEDs more affordable and efficient. Scientists are refining methods to create microscopic holes in the diodes' surfaces that will allow more light to escape and vastly increase efficiency.

“My guess is that it will be between two to three years from now before we find CFL-replacement LEDs on supermarket shelves,” says Faiz Rahman, professor of electronics and electrical engineering at the University of Glasgow and a leader in the effort to find cost-effective ways to etch those holes.

Should you change your light bulbs? Though outfitting an entire home with LEDs is prohibitively expensive for most people, trying at least one bulb could be worth it. For bedside tables, for instance, a narrow beam of light makes it easy to read without disturbing a sleeping partner. And because you won't have to think about changing them for years, they're a particularly good option for hard-to-reach places such as high ceilings.

“The future of LED-based bulbs,” Rahman says, “is bright.”