What's smaller than a dot on a ladybug's back, provides as much light output as a typical light bulb, yet is so energy efficient that the U.S. Department of Energy estimates it will cut our national consumption by 29 percent by the year 2025?

It's the LED, or light-emitting diode, a form of solid-state circuitry similar to the chips found in your computer. In the lighting industry, it is the biggest breakthrough since Thomas Alva Edison invented the incandescent light bulb some 123 years ago. It also promises to change the way we look at lighting. Yes, everywhere.

"We use lighting for two reasons: for effect and for illumination. LEDs will impact both of these areas," says Paul Gregory, principal, Focus Lighting of New York City (212-865-1565; www.focuslighting.com), which provides lighting design and installation services for commercial and residential clients around the globe, including the Hudson Valley. "Because of their miniature size, LEDs are being used as design elements, such as 'washing' a wall behind a bar area with light, even sequencing a range of lighting colors or a specific color on a specific day and time. And I am also confident that it is only a matter of months before manufacturers will be able to produce a true white light with LEDs, which will bring the light source into a much broader range of applications. Unlike even the best energy-saving compact fluorescent bulbs that can burn up to 25,000 hours, LED bulbs will burn for over 100,000 hours."

No kidding. In some applications, such as lighting a car's control panel, headlamps and taillights, or interior overhead lights, LED light sources may end up being a one-time installation-in-the-factory proposition—they may actually last longer than the power transmission or body of the vehicle.

Manufacturers are also talking seriously about mounting a cluster of LEDs on a screw base and enclosing them with an optical lens cap, and offering the product as an alternative to the typical light bulb. Though you shouldn't expect to replace it anytime soon: It should last 10 or more years with normal use. And with LED light sources, you don't have to worry about breaking the filament—there isn't one.

"Don't expect the standard incandescent light bulb to go away. Costing 25 cents in many instances, it's cheap and it does the job," says Patricia Rizzo, who heads up the residential program at the Lighting Research Center that is part of Rensselaer Polytechnic Institute of Troy, N.Y. (www.lrc.rpi.edu), and is the leading university-based research center devoted to lighting. "However, there are numerous applications in the home where LEDs will prove invaluable."

LEDs are on the cusp of becoming a practical solution for the homeowner. Today, they are finding their way into high-end applications, such as the aforementioned wall washing and pathway-marker and accent lighting. Consumers can, however, find simple LED products on the market today, including flashlights, night lights, headlamps, solar-powered landscape lighting, and holiday lights. LEDs also illuminate our cell phone receivers and the control dials in many new major home appliances. And don't forget mood lighting. There are a number of companies offering lamps shedding a whole rainbow-range of colors that are guaranteed to warm the glow in an interior space.

Osram Sylvania?s DOT·it lights are ideal for task or accent lighting and can be placed anywhere. Small enough to fit in the palm of your hand, DOT·it lights are completely wireless and adhere to just about any surface without marring. Their output, about 6 lumens, is less bright than a typical flashlight, but with fresh AAA batteries, the LEDs will last for years. $10 at major automotive and general merchandise stores.

"Once LEDs become cost competitive and the white light product is perfected, they will migrate quickly into new home construction and renovations," said Donna Cregin, a specification sales representative with Light Spec in Albany (518-371-9214). "Perfect applications are for undercabinet lighting in the kitchen, night lights, marker lighting on stair risers, and as accent lighting on artwork, much the way we use halogen lighting today. Theoretically speaking, homeowners may never have to change light bulbs during the time they live in a home again."

Rizzo said the biggest issue holding back LEDs in their adoption in home lighting is lack of standardization. "We're looking at a bureaucracy of agencies taking action here. The Lighting Research Institute is providing much of the research that they will use."

She added that while LED light sources won't be a direct replacement for incandescent light bulbs because of the cost factor, she does think they will leapfrog compact fluorescent lamp products because of their style.

"Let's face it: LEDs are sleek and sexy. They're great imbedded in floor tile or in accent tile around spas and pools. They also are great in high-maintenance applications, such as that light fixture in a center hallway that's about 25 feet off the ground."