LEDs, or light-emitting diodes, are a form of solid-state lighting that is extremely efficient and long-lasting. While incandescent and fluorescent lights consist of filaments in glass bulbs or bulbs that contain gases, LEDs consist of small capsules or lenses in which tiny chips are placed on heat-conducting material. (See References 4)
Size and Efficiency
LEDs measure from 3 to 8 mm long and can be used singly or as part of an array. The small size and low profile of LEDs allow them to be used in spaces that are too small for other lightbulbs. In addition, because LEDs give off light in a specific direction, they are more efficient in application than incandescent and fluorescent bulbs, which waste energy by emitting light in all directions. (See References 2)
The life of a high-power white LED is projected to be from 35,000 to 50,000 hours, compared to 750 to 2,000 hours for an incandescent bulb, 8,000 to 10,000 hours for a compact fluorescent and 20,000 to 30,000 hours for a linear fluorescent bulb. LED lifetimes are rated differently than conventional lights, which go out when the filament breaks. Typical lifetime is defined as the average number of hours until light falls to 70 percent of initial brightness, in lumens. LEDs typically just fade gradually. (See References 3)
Conventional lightbulbs waste most of their energy as heat. For example, an incandescent bulb gives off 90 percent of its energy as heat, while a compact fluorescent bulb wastes 80 percent as heat (see References 4). LEDs remain cool. In addition, since they contain no glass components, they are not vulnerable to vibration or breakage like conventional bulbs. LEDs are thus better suited for use in areas like sports facilities and high-crime locations. (See References 1)
Poorly designed LEDs may not be long-lasting or efficient. LEDs that are EnergyStar-qualified should provide stable light output over their projected lifetime. The light should be of excellent color, with a brightness at least as great as conventional light sources and efficiency at least as great as fluorescent lighting. The LEDs should also light up instantly when turned on, should not flicker when dimmed and should not consume any power when turned off. (See References 4)
Lexa W. Lee is a New Orleans-based writer with more than 20 years of experience. She has contributed to "Central Nervous System News" and the "Journal of Naturopathic Medicine," as well as several online publications. Lee holds a Bachelor of Science in biology from Reed College, a naturopathic medical degree from the National College of Naturopathic Medicine and served as a postdoctoral researcher in immunology.
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