LED Takes On fluorescent In Troffers

www.tedmag.com
By: Craig DiLouie

According to the DOE, four out of five lamps in service in commercial buildings in 2010 were fluorescent, with a majority used in troffer (cross between “trough” and “coffer”) luminaires. Available in standard 1x4´, 2x4´, and 2x2´ 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. The DOE estimates that energy savings for an individual project can be more than 25%, and 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 with LED 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,” said Eric Stevenson, product general manager, indoor LED fixtures, GE Lighting (gelighting.com). “Further, the ability to control LED is unsurpassed by other lighting technologies. From occupancy sensors and daylight harvesting to 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. The DOE estimates that the installed base of LED troffers increased from an estimated 40,000 units in 2010 to nearly 700,000 units in 2012. Manufacturers report that demand has escalated over the past two years, estimating that more

than 15% 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,” said Heather Milcarek, director, trade marketing professional, Philips Lighting (philipslighting.com). “For many applications, LED products have become an everyday shelf stock item that distributors need to have on hand to avoid losing business to a competitor.”

David VanSpybrook, director of sales enablement, Cree (cree.com), agreed, noting, “As LED technology advances, it is important for customers to understand that LED lighting is viable, high performing, and 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.”

LED recessed troffers typically operate at a 20% higher efficacy than traditional fluorescent systems operating at about 100lm/W. Some products have achieved efficacies as high as 150lm/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 effciency and visual comfort. In addition, 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—the quick and efficacious approach,” said Milcarek. “Now we are seeing more thoughtful designs that aim for that balance of efficacy and visual comfort.”

The DOE states that LED troffers are generally comparable in light output to two lamp troffers, although there are products available that produce light output comparable to three- and four-lamp troffers.  Contemporary light level recommendations are lower than when most commercial buildings were built, allowing for 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.

SUITABILITY
LED troffers are suitable for new construction and retrofit. With nearly 1 billion linear fluorescent luminaires currently installed in the United States, the existing buildings market is an attractive sales opportunity

“The proliferation of LED products represents a huge opportunity for distributors,” said 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 the 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 good uniformity of light levels across the task plane. (Many LED troffers emit light in a controlled “teardrop” pattern, with some products emitting a small amount of intensity above 60˚ to place light on high walls and brighten the ceiling plane.)

SELECTING THE RIGHT PRODUCT
LED is still a young technoogy and should be viewed cautiously during product selection. Distributors should look for performance that satisfies criteria, is backed by testing to industry standards, and offers strong warranties. It is often desirable to request product samples and encourage a mock-up prior to commitment.

Distributors should also continue to become educated about LED lighting and its suppliers.

 “To effectively sell LED products, a distributor’s sales team must be able to educate the customer about the benefits of the new technology vs. traditional lighting options,” said 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 agreed: “It is important to understand the detailed specs and warranties of the lighting that is being purchased/specified make sure you are 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 (ngldc.org) and the DesignLights Consortium’s (DLC) Qualified Products List (design lights.org), which is used by many utility incentive programs. The DLC criteria (v.2.1) require:

1. Minimum CRI of 80

2. Minimum 50,000-hour rated life (L70)

3. Minimum five-year warranty

4. Minimum luminaire efficacy of 85lm/W

5. Minimum light output levels depending on the size of the Troffer

“The biggest benefit to pitch to customers is that ‘LED is going to save you money on reduced energy and maintenance costs,’” Stevenson said. “With performance continually improving and price points becoming even more affordable, the time for LED is now.”

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