A lighting revolution is just beginning, and light-emitting diodes (LEDs) are leading the way. By the Department of Energy’s (DOE) most recent count in May 2013, LEDs represented less than 4 percent of overall installed lighting in the United States. Market-ready LEDs are in a continuing state of development, so now is the time for electrical contractors (ECs) to do their groundwork as lighting’s future goes digital and gets a bit more complicated.


“LEDs bring a global rethink,” said Kevin Willmorth, owner of Lumenique LLC, a lighting product development and consultant firm in Germantown, Wis. “They introduce us to a new era of lighting as an appliance. But this new era will also be more complex when specifying and installing. Upfront homework will go a long way in making better, more informed choices for your clients.”


Willmorth feels learning on the job isn’t enough when working with LED lighting, especially at the rate the technology is advancing.


“You can’t make assumptions with LED lighting or draw an equivalence based on power,” he said. “For instance, I feel ‘watt’ is an obsolete term. We need to wean ourselves from it. Once you know what lumens are [the amount of light a product emits], that’s a start but not where it ends when you consider the LED product.”


Applications and usage


LEDs’ small-market penetration in the United States is expected to dramatically change. Navigant Research, the authors of the DOE’s May 2013 report, “Adoption of Light-Emitting Diodes in Common Lighting Applications,” forecast more than 75 percent of all lighting sales by 2030 will be LED. The study looked at adoption of LED indoor lamps, indoor luminaires and outdoor luminaires within nine applications: household-style A-type bulbs, directional, decorative, MR16, downlights, troffers and other common fluorescent fixtures, high-bay, parking, and streetlight.


“We’ll see how market penetration has grown when we release the results of a new 2014 survey this spring,” said Kelly L. Gordon, program manager, Pacific Northwest National Laboratory (PNNL), a DOE government research laboratory in Richland, Wash. “What we do know is LED sales are increasing rapidly year to year, so use should rise. The small reflector lamp category had the highest installed penetration rate to date, 16 percent in 2013. LED outdoor lighting usage measured about 6 percent.”


Gordon said that controls, interoperability and versatility will drive LED growth, but more standards are needed to allow components and systems to communicate and be more interchangeable.


“Standards progress is traditionally slow but is moving fast in the LED and lighting controls field,” Gordon said.


Orb Optronix, a wholly owned subsidiary of CSA Group, is an LED test, measurement and engineering services company in Kirkland, Wash. 


Rand Lee, director of operations for Orb Optronix, sees U.S. standards and certification programs driving manufacturers to offer better domestic LED products.


“The industry wants to make sure LED products don’t get a bad name through disappointing performance, which would slow adoption,” Lee said. “Setting a bar with things like Energy Star and the Design Lights Consortium has helped keep low-quality products off the market. Prices are also really coming down, though [they are] still a hurdle.”


Gains and shortcomings


In recent years, LEDs have undergone marked technological gains, and developments are still coming.


“We are seeing continued advancement in color rendering and mimicking of other light sources; dramatic efficacy gains; new forms, including flexible materials; task lighting growth; and larger LED arrays for products such as downlights and illumination of larger spaces,” Lee said.


While LED technological advancement continues at a rapid clip, its pace is a bit of a double-edged sword.


“For instance, manufacturers develop ever higher efficacy chips that lower LED cost while producing less heat,” Gordon said. “While this is good for the technology, it’s bad for specifiers trying to keep up.”


“Obsolescence is the biggest hurdle and challenge and is not being completely addressed,” said Lara Cordell, director of technology for Wiedenbach Brown, in Yorba Linda, Calif. The firm specializes in providing energy-efficient lighting and electrical solutions to national retail and commercial accounts.


“Construction projects lasting three to five years or even one year may be specifying LED systems that will already need upgrading once the building is up and running,” Cordell said. “What’s available today might not be tomorrow. If a diode changes, can its replacement be swappable? Will light distribution change? Fixture manufacturers can move from generation one, to two, to three in the lifetime of a construction project. You need to contact the manufacturer.”


Without a proper understanding of how LED lighting works, light distribution can be especially vexing.


“We were brought in late to a project,” Willmorth said. “The LED lighting was already selected for an outdoor architectural application. No one took into account how the beam angle from an LED downlight would be different from the metal halide it was replacing. While both offered a 25-degree light angle, the LED beam was more compressed leaving dark spaces. Remember, the optic that surrounds LEDs is different, more precise than traditional lamps. Its center beam’s candle power is where you look as a comparative.”


To remedy the lighting gaps, Willmorth and the LED manufacturer reinstalled luminaires with 40-degree center angles. ECs who can read photometric data can help project teams and clients make the right LED lighting choices.


“Look for total lumens and the color rendering index [CRI] and correlated color temperature [CCT],” Gordon said. “Read the luminous intensity chart to discover where the light is going. Is it a narrow beam, a circular pattern or a batwing? In outdoor applications, you want light to be directed down. Distribution is important when selecting LED lights.”


End-of-life variability


LEDs come with the manufacturer’s life estimation, typically L70. This represents the hours of operation until the LED’s light decreases to 70 percent of the initial output. The lifespan can be lessened by several elements. Heat is the biggest culprit.


“In our investigations of product failures in the field, the cause most often has been an LED fixture operating in temperatures that exceed its limit,” Willmorth said. “Heat is a disaster with LED products. LED optics are often plastic or polycarbonate. The drivers may be heat-sensitive. Heat layers can form in certain parts of the fixtures. You simply can’t exceed heat tolerance for LED. Cold doesn’t bother them, but heat does.”


Many factors can contribute to heat exposure.


“Fixtures mounted in a commercial office dropped ceiling are generally fine, as there is air circulation in the space above the ceiling,” Gordon said. “An LED lamp in an insulated canister, however, can be problematic because there is minimal air flow, and the temperature around the lamp can be high. MR16 reflector lamps are one of the most common LED lamp types but their small [2-inch diameter] size provides little surface area for dissipating heat. They should not be used in enclosed fixtures or in fixtures with lenses over the LED lamps that can trap heat.”


Willmorth said it is important to be realistic about LED life performance.


“In a commercial environment, 50,000–70,000 hours is likely, but dirt on the lens or optics does need to be cleaned,” he said. “Dirt cannot accumulate on the thermal pathway. Expect a life range between maybe 4–10 years based on usage. Fixture outages are likely to appear at 35,000–40,000 hours. Issues with the power supply or the driver might occur in two to four years.”


Lee said that the aging of lenses or reflectors can also cause lumen-output degradation. While his firm does some testing in this regard, he stressed it comes down to the manufacturers’ due diligence in the quality of their components and subcomponents.


LED color rendering has always been part of its “cool” factor. Recent lighting submitted in the DOE’s Next Generation Luminaires competition has shown such improvement that some judges have wondered if color quality is still an issue for LEDs. However, Gordon said color stability can still be an issue.


“How the product is used and its environment (especially temperature) can cause color shift,” she said. “This is a real problem in healthcare, museums and some retail, such as clothing [stores]. The Illuminating Engineering Society is working to develop improved metrics for color rendering. The goal isn’t to do away with CRI but develop other metrics to augment CRI.”


It would follow that lighting controls could favorably extend LED lifecycles. When dimming, occupancy controls or daylight harvesting is applied, LEDs are exposed to less heat and enjoy cooler operation and lower power tasking.


“Some in the industry, like the Connected Lighting Alliance, are looking at common protocols to enable lighting system components and controls to talk to each other,” Gordon said. “Most systems, in one way or another, are currently proprietary. Companies right now want to differentiate themselves.”


She said that, if you are locked in over time with completely proprietary LED lighting control systems, ensure the client is comfortable with that fact and carefully consider the manufacturer’s warranty and its track record.


“It will take years for some synergy to develop in LED product forms, optical arrangements, drivers, power supplying,” Willmorth said. “Learn to read photometric files, get product information and stay up-to-date. Product generations will come at you one after the other. By learning how to do a better job on the front end, you not only [will] be prepared for the LED, but whatever will come after it.”