As incandescent lights or standard light bulbs are phased out of the market, the demand for light-emitting diodes or LED’s is increasing sharply. These small but powerful lights use much less energy than standard light bulbs and produce very little amounts of heat. This ends up saving on cooling costs as well as electricity costs. Consumers will undoubtedly save money by switching to LED lamps. Not all LED lighting is the same, however, and comparison of different brands can be difficult. You should speak to a lighting professional first if you are planning to retrofit a large area like a home or office space.
Longevity As Compared To Regular Light bulbs
The rated life of an incandescent bulb is measured by failure rate. Large numbers of bulbs are illuminated, and when 50 percent of the bulbs have failed, the average lamp life is said to have been reached.
Unlike incandescent bulbs, LED lamps have no filament to burn through. Before they fail, they become dimmer. This dimming is called lumen depreciation, and LED lights may operate for a long time at significantly reduced output.
New Longevity Standards
To evaluate LED lamps consistently, a standard has been developed that measures the output of the LED after 6,000 hours of use. That output is compared to the initial output, and a lumen maintenance curve is graphed. The lumen maintenance curve allows engineers to predict the time when the light output will fall below a certain level. The level usually cited is L70. This is the time when the LED output is predicted to fall to 70 percent of its initial value. The L70 figures, because they are obtained in a standardized test, can be used to compare one LED lamp with another.
The same test is used to determine the rated life of the LED. This term essentially means the same thing for LEDs as it does for incandescent bulbs, but the LEDs are never actually observed to the point of failure. Instead, the rated life is extrapolated from the lumen maintenance curve. Instead of predicting when the output in lumens will drop to 70 percent of the initial output, the extrapolation is taken to the point where the LEDs are predicted to emit no useful amount of light.
New Optical Standards
Optical safety standards have also been developed for LED lamps. Many powerful LEDs, such as super luminescent diodes or high-radiance diodes, border on the operational standards of lasers. Optical safety standards determine what level of emitted radiation is acceptable from these new diodes. The radiation regulated by these new standards is electromagnetic radiation. It should not be confused with the radiation associated with isotopes and radioactivity. The optical safety standards will become more important as new LED technologies emerge to facilitate data transmission through fiber optic cables.
As you can see, LED technology is growing steadily as more and more consumers demand and embrace energy efficient lighting options. As this new technology saturates the marketplace, choices will become easier and much less cost prohibitive. If you are currently considering a retrofit of your facility or home, check out the EERE website for tax deduction tools and ideas or speak to a qualified lighting professional who can help.
The opinions expressed in this article are solely those of the author, Danielle Stewart is a lighting designer who is interested in helping businesses learn about the values of retrofitting. She is also a design consultant for commercial LED fixtures. She blogs for P-2, a manufacturer of energy efficient lighting and a resource for energy efficient lighting information. Follow [P-2] for answers to your energy questions: @p2lighting and Facebook!