White-light-emitting LEDs are rare, and most LED bulbs, which consist of clusters of individual LEDs, have phosphor coatings that glow with white light when excited by light from the LED clusters. LED bulbs sometimes contain complex solid-state circuitry.
Economic Efficiency
CFLs produce light via the excitation of gas inside the curved tube that forms the bulb, which is more efficient than producing light by heating a filament — the process that occurs inside an incandescent bulb. By comparison, the production of light by an LED is even more efficient. To produce 800 lumens of light, an incandescent bulb consumes 60 watts, a CFl 13 to 15 watts, and an LED only 6 to 8 watts. Moreover, LEDs produce virtually no heat and last six times longer than CFLs and over 30 times longer than incandescent bulbs. The initial cost of an LED can be 5 times, or more, greater than that of a CFL, however.
Light Quality
One of the drawbacks of LED clusters is that they are directional. This makes them ideal for spotlights, but not as well suited for ambient lighting. Their directionality isn’t as noticeable inside a phosphor-coated casing, because the entire casing glows, but the bulk of the light still emerges from the top of the bulb. The quality of light that an LED emits depends on the circuitry of the bulb, and there’s a large difference between bulbs. The best bulbs, which include high-powered circuitry, produce full-spectrum white light comparable to that produced by halogen bulbs — high-temperature incandescent. Lower-quality LEDs can be comparatively dim.
Health Considerations
The Occupational Safety and Health Administration has identified flickering from fluorescent bulbs as a health hazard, but because LEDs convert alternating to direct current, they never flicker. Moreover, LEDs contain no mercury — a component of CFL bulbs — and can be safely discarded. A third advantage of LEDs over CFLs is that the former emit no ultraviolet light, and you can place one on a desk next to you without fear of absorbing radiation. Compared to incandescent bulbs, LEDs generate virtually no heat, and an unattended LED presents little risk of starting a fire.
Commercial LED Applications
One the most cost effective applications of LED lights is in businesses where the lights are on all day long in a typical office or warehouse commercial environment. The return on investment for these typical applications is 2-3 years. Businesses are better positioned to invest in this technology today and receive an immediate savings on their power bill.
