Calculating LED Life

By Jeff Gavin | Apr 15, 2016
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For the ease light-emitting diodes (LEDs) can offer in providing an effective, low-draw and energy-efficient lighting solution, the considerations to their use are many. The best service you can provide is a bit of mythbusting regarding true LED end-of-life. While LEDs run impressively longer than other sources, many variables affect their performance. Understanding and communicating those features will leave customers satisfied and confident in the lighting choices they make.

“With a diverse array of available color temperatures, lumen outputs and capabilities, such as dimming and even color-tuning, there are certainly more considerations,” said Rose Jordan, program manager at Midwest Energy Efficiency Alliance (MEEA), Chicago. To her, LED products merit the extra deliberations because they provide specified ambience and lighting conditions with precision. They also can achieve deep energy savings when adding sensors and controls.

Lara Cordell is director of technology and national account executive for Wiedenbach-Brown (WB), a commercial lighting distributor and lighting solutions adviser headquartered in Hawthorne, N.Y., though she works in Yorba Linda, Calif. Cordell is a strong advocate for LED lighting. She finds its success tied to knowing how it best behaves in its environment. Only then can customers set realistic expectations to LED life and performance at key points within its lifespan.

“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?”

L70 is a typical life-cycle measure, though depending on the lamp type, ratings could run L50 or less or as high as L80. Each represents the percentage of LED original light output during its quoted lifetime before light quality incrementally decreases.

“Providing customers with a viable lamp life is an important service the electrical contractor can supply, but you first need a good product and a thorough understanding of the influencers on a LED bulb or fixture’s life,” said Randall S. Johnson, president 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 negatively 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 materials.

“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 a hotter climate. Some roadway LED fixture manufacturers do show you the life range of their product based on geography. In another measure, adopters of LED street lighting might not use the manufacturer end-of-life as their gauge for relamping but rather light levels that fall below a set safety standard of proper illumination for traffic or pedestrians,” she said.

Johnson and Cordell said a combination of engineering and better materials has helped LEDs in many applications.

“Other marginally performing LED products like high-wattage high-bay LED fixtures now offer better light distribution and are viable candidates for school gymnasiums, warehouses and other high-bay applications,” Johnson said. “I find that providing LED product demonstrations for projects happens much more often than with other light sources.” (See “Getting It Right,” page 38, for more on LED lighting demos.)

Light levels, chips and broadening warranties

Though LED lamps may have the same part numbers, their chips may come from a variety of manufacturers. That can be a factor in performance and product life.

“You can extend LED lighting life by replacing failing components, but such components aren’t off–the-shelf available,” Cordell said. “For us, one solution is negotiating with the manufacturer to include color shift in their warranties. Some warranty lumen output as well, not just lamp failure.”

Dealing in bigger projects, national accounts and large volumes of LEDs gives WB some influence with manufacturers.

Cordell also emphasized the importance of taking light level readings at the beginning of a project and determine the best levels going forward.

“The luminance level you glean through installation photometric testing should be used to factor in diminishing light levels and trigger relamping schedules,” she said. “Other influencers include dimming, ramp ups for consistent light levels, or lights [running] only eight hours a day.”

Cordell predicted that, in time, LED fixtures will come with life indictor lights. Juno Lighting Group currently has a red light indicator on its fixtures to signal needed maintenance. She has requested this feature from other manufacturers, but it’s often an added cost. In her time with LED products, Cordell has observed LED lights won’t last forever but “five to six years” is a realistic average.

Encouraging a lighting maintenance plan

Encourage proper maintenance of LED lighting to help extend product life. It is also a way in to extend a relationship with a customer.

“For the ECs [electrical contractors], you may cover your work with a one-year warranty,” Cordell said. “Maybe it is part of project package offered through the general contractor. After that period, step up and offer an add-on maintenance service.”

Johnson agreed and described such a plan.

“We work with a lot of electrical contractors,” he said. “To keep the initial quote down, ECs might offer maintenance service as an add-on. For dedicated LED fixtures, cleaning them is important. Failed LED chips are not easily replaceable for most dedicated fixtures. So set a cleaning schedule. Don’t forget occupancy and other sensors, too. Calculate the times you will “relamp” so it becomes part of your customer’s operation.”

Lighting controls should be commissioned at the start of an LED installation. Clients should understand the warranty, too.

“We have an electrical services division that serves our retail customers,” Cordell said. “We also have an order person so if a customer calls with an LED lamp failure, we can call up the warranty period. Too often customers pay for a replacement product unaware of its warranty status. We also found working with LED replacement parts is not easy as there is no part number for the driver or the LED board. That’s something to keep in mind.”

While LED remains the most costly lighting solution at purchase, it can also be the most cost-effective when factoring in energy usage, bulb life, replacement, and associated labor costs. Selling a customer on LED lighting is much more of a conversation than a pitch.

“We remain in an education mode when it comes to LEDs, sharing information with the owner,” said Johnson. “I recently spent two hours with an owner talking about the pros and cons of LED. It takes time to correctly present and integrate LED into a lighting solution.”

When selecting LED products, Johnson advises electrical contractors to start with bulbs that are Energy-Star-rated and then research manufacturers.

“Did the sales rep talk about light levels or performance of the light output?” Johnson asked. “If they are just talking about lamp life, or savings alone, that should trigger some questions. Many of these vendors are approaching your customers or potential customers without assessing the project space—where the lighting is being considered—but you can. Help your clients understand how long their LED solutions should be expected to last.”

Meanwhile, Jordan is encouraged by the many resources that can help professionals navigate LED choices. She recommends the U.S. Department of Energy (DOE) Solid-State Lighting webpage at

About The Author

GAVIN, Gavo Communications, is a LEED Green Associate providing marketing services for the energy, construction and urban planning industries. He can be reached at [email protected].





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