Saturday, November 24, 2007

Efficient Lighting

I've been confused by the refernces to LED (Light Emitting Diodes) lighting as being more efficient than flourescents. It's popular knowledge that incandescent bulbs are considered inefficient because they give off more heat energy then light energy. In other words they are basically a form of heating that give off light as a by product. The incandescent light bulb was a fabulous invention by Edison but we now have the technology to light our offices using less energy. The flourescent 4' long tube is the standard for most offices but many of us hate the flickering light, the quality of light and the noisy ballasts that are associated with these fixtures. The release of the T8 flourescent has addressed these problems and you can now find them used in all good quality commerical fixtures. Compact flourescents have made flourescents more friendly, the light is warmer, they screw into standard incandescent fixtures and they last ten times longer than incandescent bulbs! But what about the LED? It's touted as being even more efficient then flourescents and they do not contain trace amounts of mercury like flourescents.

LED technology is taking off and new advances are being made everyday to widen their applications since they use so little energy and last three times longer then flourescents! White LEDs give off a lot of light while not using very much energy but readily available products are limited to fixtures which light a small area such as task lighting, path lighting, and exit signs. LED light fixtures with reflectors that "spread" and "throw" light so that it can be used for general or overhead illumination are becoming commercially available.

Lumens per watt gives the amount of light given off by the energy used. Below I've listed lumens per watt for the different types of lights discussed in the article.

Incandescents give 15 lumens per watt
Compact Flourescents give 50-60 lumens per watt
LEDs currently give 50-60 lumens per watt but this number is increasing rapidly
Standard flourescent tubes have an efficiency of 60-65 lumens per watt
Flourescent T8s give 85-90 lumens per watt

1 comment:

Greenette said...

Rockefeller Center's Christmas Tree is lit with LED lights this year! Check out the article:

According to Mayor Bloomberg, the tens of millions of New Yorkers and tourists who see the tree this year will hopefully “…see an example of green leadership which may inspire them to make greener choices in their own lives.”

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