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LEDs Conserve Energy

CRUZ R. PEREZ | Eco-Green Sustainable Landscapes

DRIVEN BY A GROWING INTEREST in smart eco-friendly solutions, as well as rapidly-rising electrical costs, the entire lighting industry has turned its attention to high-efficiency products. Since 2002, average electricity rates in the United States have risen by more than 25%, so there is a real demand for solutions that control energy use and that matches trends toward green lifestyles.

Experts predict that LED will rapidly replace traditional incandescent sources, providing equal light output while using 80 to 90% less energy. Once used solely as indicator lights for electronics, LEDs have evolved into a major lighting technology that will change the future of how professionals light a landscape.

What is an LED?

A Light Emitting Diode (LED) is a semiconductor that converts electricity into light. It is a solid state device that does not contain a breakable filament. LEDs were first commercially introduced in the 1960s and were initially used as indicators in electronic displays. In more recent times, LEDs have been increasingly used in general illumination applications. One area where they provide an ideal mix of efficiency and output is landscape lighting.

Unlike a halogen lamp that generates significant heat together with light output, LEDs themselves do not generate any infrared heat. This allows the fixture lens to remain entirely cool to the touch, a significant advantage for in-ground and accent fixtures.

Are LEDs reliable?

LEDs have a rated life based on the time it takes for the light output to decrease to 70% of the original output, which is typically about 50,000 hours or 17 years of normal residential use. Unlike an incandescent lamp, LEDs include no filament, so they do not “burn out”; they gradually decrease in their light output, beginning many years after initial installation. This extreme longevity makes LED lighting a true fit-and-forget solution for tree-mounted fixtures and other locations where re-lamping is difficult. A typical incandescent fixture will need to be re-lamped 10 or more times during the life of a typical LED fixture.

How efficient are LED fixtures?

The simple answer is that the typical LED fixture will produce

the equivalent light output using about 80% less energy. A good comparison is a 20-watt MR-16 lamp and carefully-tuned 3-emitter LED array with high-performance optics, using about 4.5 watts.

These two provide light output that is virtually equivalent in lumen output, color temperature and beam control.

Dramatically lower wattage consumption by each LED fixture allows you to significantly increase the number of fixtures on each cable run and correspondingly decrease the size of the system’s transformer.

The combination of these two factors—lower power use and self-balancing fixtures—can virtually eliminate the need for laborious voltage drop calculations in many systems. It can also allow for the addition of more fixtures into many installations without affecting the performance of the balance of the system.

How much energy would a typical residential client save in one year with an all LED installation versus an equivalent one with halogen lamps? Considering an installation using 900 watts of halogen lighting, operated nightly for 10 hours, the annual energy cost at the local rate of $0.145 per kwh is approximately $476. The same system with an equivalent number of LED fixtures with equivalent lumen output would cost approximately $95 annually to operate.

In addition, the halogen system would require re-lamping of the fixtures after approximately one year of operation (assuming a typical halogen lamp life of 4,000 hours). The LED system offers an average life of 50,000 hours or 17 years of use in this application.

EDITOR’S NOTE: Cruz R. Prez is director of sales and marketing for Vista Professional Outdoor Lighting, Simi Valley, California.

 
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