Intro To LED Lighting
By Jeffrey R. Dross
LED lighting is an energy- and cost-efficient alternative to tra
Lighting represents 15.5% of a typical American electric bill, and
that percentage has been rising since 2001 because other
electricity-consuming products have become more efficient. The
percentages representing our monthly expenditures for hot water,
cleaning appliances, temperature conditioning, and refrigeration are
going down, while the percentage representing our monthly expenditure
for lighting is going up. All this will change as Light-Emitting Diodes
(LEDs) begin to take hold of mainstream illumination.
LEDs are nothing new. The first experiments in electroluminescence
were conducted over 100 years ago in 1907. It wasn’t until the 1960s,
however, that those pioneering experiments resulted in visible light. In
a few short years, visible red LED chips were put to practical use in
early calculators and contemporary wristwatches. Red was followed by
other colors, and in 2002 “white” light was finally replicated in an LED
When the electrons inside the LED semiconductor change state, the diode
transforms electric current into visible light. An assortment of
phosphors and varying energy inside the chip control color. The
efficiency by which electricity is translated into light is continually
improving at a rate that can be likened to computer chip technology, far
faster than any other type of light. LED illumination appears to be the
answer to more efficient luminaires. In addition to their rapidly
improving efficacy, LEDs are better for the planet in general. LEDs do
not contain mercury, unlike fluorescent lamps, and they will also reduce
the mass of used and unrecyclable incandescent light bulbs.
LEDs are not without their challenges, perhaps the largest being
thermal maintenance. Temperature has a big effect on LED performance.
Elevated temperature will impact lifespan and lumen output. It is
incumbent on the manufacturer to control that heat.
Since the creation of “white” LED chips, lighting designers have been
experimenting with their use. Refrigerator/freezer case lighting has
always been a problematic application, because fluorescent lighting does
not work well in the cold. That is just the opposite for LEDs, and so
the industry is experiencing a revolution.
Because LED is directional, recessed cans are also excellent outlets for LED.
The LED’s compact size lends it to fit in small places, so cabinet
lighting has become a popular outlet. The same follows for cove
lighting, tray ceiling lighting, toekick lighting, and an assortment of
accent lighting used in confined locations.
Most LED lighting now consumes approximately 75% less power than
conventional incandescent or halogen lighting, yet it still provides
equal lumen output. Although the initial costs of LED products are
higher, the total lifetime costs, including electricity and the lack of
required replacement lamping, will be less. If maintenance costs are
added, that return on investment (ROI) rises. Electric costs are also
rising faster than the cost of living and current day inflation, which
means that lighting is slowly evolving into a long-term investment, like
a refrigerator or washing machine, and moving away from the low-cost,
high-maintenance entity it is today.
August 30, 2013