History of light

The history of man-made light is based on heat. Wax, oil and gas burn to product light. The filament in an incandescent bulb heats up to produce light. Gas in a fluorescent tube is zapped to illuminate. The baskic method is "Heat it up, and it glows."

For more than 120 yesrs, incanscent light bulbs have brightened and literally warmed our lives. Electric-powered bulbs were a major improvement over candle, gas and oil light sources, but they are extremely inefficient. Bulb-based light sources are far better at producing heat than lihgt-up to 90 percent of the power going into a bulb is converted to heat.

Compact fluorescent bulbs (CFLs) are more efficient, and are an excellent alternative to incandescent bulbs for Edison-socket light fixtures. However, they contain a small amount of mercury, making them hazardous waste when they break or burn out.

Now, LEDs are ready for broad deployment across general lighting applications such as parking garages and lots, streetlights and other outdoor installations. Indoor directional and down light solutions are also becoming available.

By committing to LEDs in municipal lighting, cities are making a thoughtful energy choice that will greatly benefit their taxpayers, visitors and environment.

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