LED Lightings

LED Lighting is durable solid-state lighting source that is more compact and durable than incandescents.

A Light Emitting Diode (LED) is a semiconductor device which converts electricity into light. Each diode is about 1/4 inch in diameter and uses about ten milliamps to operate at about one watt. LED fixtures require a driver which is analogous to the ballast in fluorescent fixtures. The drivers are typically built into the fixture (like fluorescent ballasts) or they are a plug transformer for portable (plug-in) fixtures. The plug-in transformers allow the fixture to run on standard 120 volt alternating current (AC), with a modest (about 15 to 20 percent) power loss. The efficacy of a typical residential application LED is approximately 20 lumens per watt (LPW), while high power LED has typical 100 LPW output, such as used for solar street lights.

Terminology

• Color Temperature -Color of light. Kelvin (K). Sunlight at sunrise is 1800K 100W Incandescent light bulb is 2850K. Overcast Sky is 6500K
• Color Rendering Index (CRI) - Light’s effect on color. Scale of 0 to 100 with sunlight at 100. The higher the number, the more “true” the color will look in that light
• Brightness - The intensity of the light. Lumens. The higher the lumens, the brighter the light
• Efficacy - The efficiency of the bulb to convert electricity into light. Lumens per Watt. More efficient bulbs provide more light using less energy
• Power - Amount of electrical energy consumed. Watts. Lower the watts, the lower the energy consumed

Benefits/Costs

LED lamps have many advantages over traditional lighting methods

• Low energy consumption – retrofit bulbs range from 0.83 to 7.3 Watts
• Long service life – LED bulbs can last up to 50,000 hours
• Durable – LED bulbs are resistant to thermal and vibrational shocks and turn on instantly from -40C° to 185C°, making them ideal for applications subject to frequent on-off cycling, such as garages and basements
• Directional distribution of light – good for interior task lighting
• No infrared or ultraviolet radiation – excellent for outdoor use because UV light attracts bugs
• Safety and environmentally conscious – LEDs contain no mercury and remain cool to the touch
• Fully dimmable – LEDs do not change their color tint when dimmed unlike incandescent lamps that turn yellow
• No frequency interference – no ballast to interfere with radio and television signals
• Range of color – LEDs can be manufactured produce all colors of the spectrum without filters, they can also produce white light in a variety of color temperatures

There are some current disadvantages to LED lighting:

• LEDs are currently more expensive than more conventional lighting technologies, and may be hard to locate
• LED are very heat sensitive. Excessive heat or inappropriate applications dramatically reduce both light output and lifespan
• LEDs typically cast light in one direction at a narrow angle compared to incandescent or fluorescent lamps so lenses or reflectors are needed in fixtures to broaden the beam (if desired)

Warranty

Warranties for LEDs can range from 3 to 5 years, depending on the manufacturer.