What is LED lighting?

LED or sold state lighting (SSL) uses light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments (used in incandescent lamps), plasma (used in florescent lamps) or gas.

How does it compare to other kinds of lighting?

LEDs differ from traditional light sources in the way they produce light. In an incandescent lamp, a tungsten filament is heated by electric current until it glows or emits light. In a fluorescent lamp, an electric arc excites mercury atoms, which emit ultraviolet (UV) radiation. After striking the phosphor coating on the inside of glass tubes, the UV radiation is converted through atoms which emit ultraviolet photons as the atom’s electron reverts to a lower, more stable energy level. At this point visible light is emitted. Typical fluorescent gas comprises mercury vapor doped with argon, xenon or krypton.

An LED, in contrast, is a semiconductor diode consisting of a tiny particle treated to create a positive-negative junction. When connected to a power source, current flows from the positive or anode side to the negative or cathode side. Electrons and electron holes, called charge carriers, flow into the junction, fall into a lower energy level and release energy in the form of a photon or light.

LED lamps have many advantages over traditional lighting methods. These include:

Cost-effective

Safe and durable

Environmentally friendly

Fluorescent bulbs contain dangerous mercury which is a hazardous material, requiring special disposal; LED bulbs are mercury free.

Quality of light

Low energy consumption – LEDs use up to 90% less energy compared to traditional incandescent lamps

Retrofit lamps range from 0.83 to 18 Watts

Long service life – LED lamps can last up to 50,000 hours*

Eliminates need to maintain and replace failed ballasts in fluorescent lamps

LED lamps are resistant to thermal and vibrational shock and turn on instantly, making them ideal for frequent on-off cycling, such as garages and basements. A typical incandescent lamp is not made to be turned on and off frequently; each time it is turned off, its lifespan is reduced.

Quality of light

Directional light makes LEDs optimal for interior task lighting.

Fully dimmable – LEDs do not change their color tint when dimmed unlike incandescent lamps that turn yellow.

Range of color – LEDs can be manufactured to produce all colors of the light spectrum and can produce white light in a variety of color temperatures.

No infrared or ultraviolet radiation – excellent for outdoor use since infrared light attracts insects LEDs do not produce excessive heat and remain cool to the touch. For example, CFL lamps operate at 200 degrees Fahrenheit while LEDs operate at 100 degrees Fahrenheit.  No interference with radio frequencies, electronic frequencies or human biorhythms. Fluorescent and incandescent bulbs have been shown to negatively impact people’s health due to the interference with radio and electronic frequencies.

Definitions & Terms