I wrote this article for the February issue of tED Magazine. Reprinted with permission.
According to the U.S. Department of Energy (DOE), four out of five lamps in service in commercial buildings 2010 were fluorescent, with a majority used in troffer (cross between “trough” and “coffer”) luminaires. Available in standard 1′x4′, 2′x4′ and 2′x2′ sizes, these luminaires are popular in applications featuring dropped acoustical-tile ceilings.
In recent years, LED technology has challenged this venerable workhorse with energy-efficient and long-life alternatives. DOE estimates that energy savings for an individual project can be 25+ percent. Energy savings can be accelerated via operation with automatic lighting controls. With dimming standard or a standard option on a majority of products, integration with controls is more attractive than with fluorescent. And with service life typically rated up to 50,000 hours, owners are promised years of reliable lighting service without changing lamps, reducing maintenance costs.
“The product portfolio for LED recessed troffers and suspended luminaires is broad with a vast variety of options in size, style, optics and color temperatures,” says Eric Stevenson, Product GM, Indoor LED Fixtures, GE Lighting. “Further, the ability to control LED is unsurpassed by other lighting technologies. From occupancy sensors to daylight harvesting and full dimming functionality, end users can enjoy the benefits of a smart, integrated lighting system that can help to further increase energy savings.”
In short, LED general lighting has come a long way in a very short time. DOE estimates the installed base of LED troffers increased from an estimated 40,000 units in 2010 to nearly 700,000 units in 2012. Manufacturers report demand has escalated over the past two years, estimating that 15+ percent of new troffer luminaires sold today employ LEDs as the light source.
“Many of the initial concerns with first-generation technology around light levels, light quality, performance and even cost have been resolved,” says Heather Milcarek, Director, Trade Marketing Professional, Philips Lighting. “For many applications, LED products have become an everyday shelf stock item that the distributor needs to have on hand to avoid losing business to a competitor.”
David VanSpybrook, Director of Sales Enablement, Cree, Inc., agrees: “As LED technology continues to advance, it is important for customers to understand that LED lighting has become viable, high-performing and is ready for mass conversion today. The cost curve and payback period for LED lighting solutions have reached the point where waiting for further advancements actually decreases the potential lifetime savings.”
In recent years, LED technology has challenged fluorescent for commercial general lighting applications. DOE estimates that energy savings for an individual project can be 25+ percent. Image courtesy of Cree, Inc.
LED recessed troffers typically operate at a 20 percent higher efficacy than traditional fluorescent systems operating at about 100 lumens/W. Some products have achieved efficacies as high as 150 lumens/W.
While efficacy is important, making LED an economically attractive alternative to fluorescent, the primary consideration is how the LED troffer performs as a lighting product. Manufacturers report that LED troffers are available that provide good light output, color quality and optical control, which is related to both luminaire efficiency and visual comfort. Some products offer color tuning, which is relatively difficult to implement with fluorescent. Others offer advanced onboard digital control and sensors.
“For troffers, there are a lot of products with the LED boards on the back of the housing that push the light directly out,” she says. “It was the quick and efficacious approach. Now we are starting to see more thoughtful designs that aim for that balance of efficacy and visual comfort.”
DOE states that LED troffers are generally comparable in light output to two-lamp troffers, though there are products available that produce light output comparable to three- and four-lamp troffers. Contemporary light level recommendations are lower than when a majority of commercial buildings were built, allowing a reduction in light levels. However, designers must note the service life of the luminaire and associated lumen depreciation to ensure light levels are met on an ongoing basis.
LED troffers are suitable for new construction and retrofit. With nearly 1 billion linear fluorescent luminaires installed in the United States, the existing buildings market is an attractive sales opportunity.
“The proliferation of LED products represents a huge opportunity for electrical distribution,” says VanSpybrook. “The upgrade to LED lighting is a race for contractors and distribution. Who will capture that upgrade opportunity?”
In existing buildings, new LED troffers generally provide higher energy savings for equal luminaire output compared to fluorescent troffers upgraded with LED retrofit kits or replacement lamps, according to DOE. While “drop in” LED linear replacement lamps are available that offer the lowest installation costs, a majority of replacement lamps require electrical modifications with associated installation costs, making new luminaires an economically competitive choice in many cases. For best results, one must note the spacing criterion of any LED option in an existing space to ensure the continuation of good uniformity of light levels across the task plane. Note many LED troffers emit light in a controlled “teardrop” pattern, with some products emitting a small amount of intensity above 60 degrees to place light on high walls and brighten the ceiling plane.
Image courtesy of GE Lighting.
LED is still a young technology and should be viewed cautiously during product selection. Distributors should look for performance that satisfies criteria, backed by testing to industry standards such as IES-LM-79, and strong warranties. It is often desirable to request product samples and encourage a mockup prior to commitment. Distributors should continue to become educated about LED lighting and its suppliers.
“To effectively sell LED products, the distributor sales team must be able to educate the customer about the benefits of the new technology versus traditional lighting options,” says Chris Dolan, Product Marketing, IGA, Philips Lighting. “There is a wide range of performance and quality on the market. Do your homework to determine which product is most appropriate given the performance, aesthetic and budget consideration.”
Stevenson agrees: “It is important to understand the detailed specs and warranties of the lighting you’re purchasing/specifying—you want to make sure you’re aware of the lifespan, engineering and reliability.”
Distributors can find a number of good products among the winners of the Next Generation Luminaires Design Competition (www.ngldc.org) and the DesignLights Consortium’s (DLC) Qualified Products List (www.designlights.org), which is used by many utility incentive programs. The DLC criteria (v.2.1) require: 1) minimum luminaire efficacy of 85 lumens/W, 2) minimum CRI of 80, 3) minimum 50,000-hour rated life (L70), 4) a minimum five-year warranty and 5) minimum light output levels depending on the size of the troffer.
“The biggest benefit to pitch to customers is, ‘LED is going to save you money on reduced energy and maintenance costs,’” Stevenson says. “With performance continually improving and price points becoming even more affordable, the time for LED is now.”
The Illuminating Engineering Society has published an introductory e-textbook on lighting, ARCHITECTURE FOR LIGHT by Kim and Paul Mercier.
Cree’s SmartCast lighting control technology now includes field-adjustable color temperature for the company’s SmartCast-enabled CR Series LED troffers. This provides dynamic and customizable color control from 3000K to 5000K in 500K increments for commercial building general lighting.
