Studies suggest that a complete conversion to the lights could decrease carbon dioxide emissions from electric power use for lighting by up to 50 percent in just over 20 years; in the United States, lighting accounts for about 6 percent of all energy use. A recent report by McKinsey & Company cited conversion to LED lighting as potentially the most cost effective approaches to tackling global warming using existing technology.
LED lighting was once relegated to digital display in laboratory, public ultilities office, Stock exchange display, basketball scoreboards, traffic lights. But as a result of rapid developments in the technology, it is now poised to become common on streets and in buildings, as well as in homes and offices. Some American cities, supported by LED companies promoted images with name of LED City including Ann Arbor, Mich., and Raleigh, N.C., are using the lights to illuminate streets and parking garages, and dozens more are exploring the technology.
There is a Website 18seconds.org is calculating and updating the number of purchased CFL light bulbs since 1 Jan 2007 in cities and states of USA. It said that it takes just 18 seconds to change an incandescent light bulb to CFL bulb as anintermediate transition for LED illumination.
From the data, Washington is the first Oregon the second and Wisconsin the third largest State as users for CFL.
LED is 2 times more efficient as compact fluorescent bulbs, currently the standard for greener lighting. Unlike compact fluorescents, LEDs turn on quickly and are compatible with dimmer switches. And while CFL contain mercury, which requires special disposal, LED bulbs contain no toxic elements, and last much 3 times longer.