“With traditional lamp sources [fluorescent, halogen, metal
halide], their end-of-life is obvious—lumen value can drop 50
percent after averaging 10,000 hours of operation or the lamp
simply fails,” Cordell said. “You know when it’s time to change
out the lighting. With LED, lessening lumen output isn’t as
obvious. In fact, most failures with LED are driver-related.
The trickiest thing about LED life is not understanding how it’s
going to fail. It may have an L70 rating, but who’s tracking it?”
of US Lamp Inc., Green Bay, Wis. “You need to be significantly
more thoughtful when considering LEDs validating claims of
energy savings, color rendition, ambiance, dimming ability,
and impacts on product life that may also affect lumen output.
Owners that say we want LED lighting are simply specifying
the category of lighting they want. You have to speak to how it’s
applied, installed [and] used [to] provide the lighting solution.”
Johnson’s firm is also a lighting distributor and installation
adviser serving industrial clients.
Customer expectations of LED lighting will be different
based on use, be it an office, warehouse or outdoor setting. For
Cordell, defining end-of-life is specific to application and need.
“Color shift is one thing that will be noticeable and may neg-
atively affect the lighting, most notably in retail applications,”
Cordell said. “You can see shifting occur at different rates. Some
retail clients have seen LED color shifting within four years. The
retail market is high-profile. So when these customers go LED,
they need it to provide color and the right amount of it. Color shift
and lumen depreciation can be the result of heat in the fixture.”
Later generation LEDs are better at managing heat, as
manufacturers have improved heat sinks and heat-absorption
“In addition, chips for LEDs have advanced, demonstrating
a 30–50 percent performance increase,” Johnson added. “That
has allowed for a drop in bulb wattage by as much as 50 percent
while maintaining desired lumens. Low wattage means lower
heat and thermal dissipation from the chips.”
Even with advances, heat remains an LED lighting challenge.
“If a building runs hotter than ambient temperatures, you
need to factor that into LED life,” Cordell said. “Know your
indoor operating temperature when considering LED. High-bay applications must deal with heat rising. Is that detrimental
in your operation? Is your LED manufacturer offering a product
engineered to handle heat? For interior lighting, manufacturers
assume room temperatures running at 75°F to help make their
prediction of 50,000 hours or more of LED lamp life.
“Then, there’s lighting fixtures. Such fixtures operating in
Phoenix versus Chicago will have different lamp life based on
LED life ing
Contractors must understand influencers on an LED lamp or fixture’s
life when considering large-scale retrofits.