Commercial buildings in the U.S. devote the greatest portion of their energy consumption—about 27%—to lighting, according to the Department of Energy’s “Building Energy Data Book” (http://buildingsdatabook.eren.doe.gov). It’s not surprising, therefore, that recent innovations in lighting technologies hold significant long-term potential for energy savings.
This is particularly true of solid-state lighting using light-emitting diodes. According to a recent study by Pike Research (“Energy Efficient Lighting for Commercial Markets,” at: http://www.pikeresearch.com), by 2020 LED lighting will achieve a 46% penetration of the U.S. market for lamps in the commercial, industrial, and outdoor stationary sectors.
While LEDs are coming down in cost and improving in performance, they aren’t dominating the market just yet. Fluorescent T8 and T5 lamps, which offer longevity at a reasonable price, will overtake incandescent lamps before LEDs come of age, according to the Pike Research report.
Nonetheless, there are compelling reasons to use LEDs for certain applications, such as in freezers and refrigerated cases, which is why Walmart and Target are installing LEDs in their food departments. Whereas fluorescent lamps are sensitive to temperature, “LEDs love the cold,” says Shelli Sedlak, LC, LEED AP, an electrical engineer with GE Lighting Solutions, East Cleveland, Ohio.
LED lighting can be used anywhere that incandescent, halogen, and most types of fluorescent lighting are used, says Bob Smith, director of Energy Marketing Solutions for Cooper Lighting, Peachtree City, Ga. “Ceramic metal halide lighting is beginning to be replaced by LEDs because LEDs deliver more footcandles but use less energy,” says Smith. “The color is reasonably good, and LEDs tend to cost less than metal halide.”
LED PERFORMANCE IMPROVING RAPIDLY
LEDs have come a long way in the last two years as a general lighting solution, says Stephan Schmitt, managing partner for SimplyLEDs, Garden City, Idaho, which specializes in customized LED solutions. “LEDs generate well above 100 lumens per watt, and the color rendering has greatly improved,” he says. “In the next two or three years, the cost will come down and performance will improve even more.”
However, LEDs are still fairly expensive. According to a July 2011 report by Illumination Arts, a lighting design firm in Bloomfield, N.J., a compact fluorescent lamp (CFL) delivering 1,430 lumens costs $100 (distributor cost), while an LED delivering 1,500 lumens costs $250 (distributor cost) — a 150% increase.
Schmitt notes that the cost of LEDs depends on the type of installation. For new installations, he says, they’re two to four times as expensive as metal halide or other high-performing high intensity discharge (HID) systems, and four to eight times as much as CFLs. In retrofits where the existing housing is used, LEDs cost two to three times as much as installing modern HID fixtures. However, for expensive lighting infrastructure, LEDs can actually be cheaper (see “LEDs Make a Splash at Boise’s Y”). In applications where lights are kept on 10-12 hours a day, the total ownership return on investment with LEDs can be quite attractive, says Schmitt. “If you consider the energy savings, reduction in maintenance costs, and utility rebates, the ROI for LEDs versus high-intensity discharge lighting is typically less than three years—often in the one- to two-year range. Compared to compact fluorescent lighting, the ROI is still longer than four years.”
It’s important to note that LEDs are not a one-size-fits-all solution. “Halogen is still a good source that offers very high color rendering or color saturation, which is very important in retail settings,” says Cooper Lighting’s Smith. “LEDs aren’t as effective in those cases.”
Faith Baum, IALD, LC, IES, LEED AP, principal of Illumination Arts, Bloomfield, N.J., has used white LEDs for task lighting, step lighting, low-level landscape lighting, and exterior lighting. But she has shied away from using LEDs for general lighting, citing glare as a key concern. “Some of them aren’t dimmable,” she adds.
Baum acknowledges that the long life span of LEDs may offset their relatively high upfront cost. And she notes that LEDs have some special applications. “They’re a better solution than halogen lamps for museums and art galleries because they don’t emit ultraviolet rays that can damage artwork and displays,” she says.
FLUORESCENTS STEP UP EFFICIENCY
Fluorescent lamps are often specified for nonresidential projects because they are more efficient and last much longer than standard incandescent lamps. They come in several forms: as linear or T5HO (high output) lamps; as compact fluorescent lamps (CFLs), generally used for downlighting and wall washing; as low-mercury fluorescent lamps; and as inductive fluorescent lamps—white-light sources with good color rendering and color temperature properties. Linear fluorescents are usually installed in troffers—long recessed ceiling fixtures that are usually set flush with the ceiling. “This is where T8s and T5s give great value,” says Smith.
With fluorescents, it is important to pair the lamp with the right ballast. For example, even though T8s are a generation older than T5s, it is possible to gain efficiency if a T8 lamp is combined with one of the new types of ballast combinations. Says Baum, “We can eke out a lot more energy-efficient lighting from a T8 lamp/ballast combination than we can from other light sources.”
Halogen and ceramic metal halide lamps have also been greatly improved. “Lighting manufacturers are making huge advances in the quality of metal halide lighting for outdoor applications,” Baum says. “The efficiency of the lamps has gone way up. You’re getting more lumens per watt.”
TWO STEPS FORWARD, ONE BACK
Not everyone is convinced that LEDs are the sole solution to the lighting efficiency problem. For example, Baum’s biggest concern with the technology is that it is advancing so fast that LEDs specified for a project today may be obsolete by the time construction starts. Baum’s advice to clients: Buy shelf stock now so they can replace their LED lamps when necessary.
Architect Steve Clem, AIA, ASID, IIDA, principal of tvsdesign in Atlanta, says LEDs have a lot of positive aspects: “They’re not heat generators, and their color accuracy has improved.” However, he’s concerned not only about their initial cost but also about certain design considerations with LEDs. “In some cases, I don’t believe they have the functionality to punch light and accent surfaces as fully as halogen and metal halide lighting, ” he says.
Lighting designer Chip Israel, FIALD, MIES, LC, LEED AP, says his firm, Lighting Design Alliance, Long Beach, Calif., is incorporating LEDs more and more into projects. “But to us, LEDs are just a design tool,” he says. He advocates maximizing daylight and turning lights off whenever possible. “Whether they’re fluorescents or halides or LEDs, if you can turn them off, you’ll save the most energy. The most efficient light is the one you turn off.” BD+C
SIDEBAR: LEDs Make a Splash at Boise’s Y
Fifteen years of wear and tear had darkened the walls and ceiling of the indoor swimming pool at Treasure Valley Family YMCA, Boise, Idaho, to the point where light levels in the pool area were severely compromised. Rather than replacing the existing metal halide fixtures, the YMCA chose to go with LEDs.
LEDs offered several advantages over other systems. They could be installed without the need to shut down the pool, which is open 20 hours a day; and the installer, SimplyLEDs, of Garden City, Idaho, was able to use the existing lighting infrastructure, which helped keep the cost of the project under control.
SimplyLEDs custom engineered a solution using LED arrays manufactured by Bridgelux, Livermore, Calif. The Bridgelux arrays replaced 66 metal halide two-lamp fixtures, each fixture consuming 920 watts. The new system consists of 4 Piazza Series LED modules using Bridgelux ES Series LED arrays at 150 watts per fixture, an energy savings of 770 watts per fixture. Custom-designed reflectors achieve uniform light distribution with minimal water glare.
The retrofit resulted in an annual energy savings of $20,000, yielding a payback of less than three years. Over the lifetime of the installation, the YMCA will realize more than $100,000 in savings, according to Bob Deely, CEO of SimplyLEDs. Moreover, says Deely, the use of LED solid-state lighting means that the entire installation will be virtually maintenance free, further reducing operating costs for the YMCA.
SIDEBAR: Custom Fixtures Help Showroom Gain LEED Platinum Status
Though technically a renovation of a vacant warehouse, the Herman Miller Showroom in Los Angeles was more like new construction, recalls lighting designer Chip Israel, FIALD, MIES, LC, LEED AP, president of Lighting Design Alliance, Long Beach, Calif. “Pretty much all we had was the roof and the outer walls,” he says.
But the bowstring wood ceiling trusses sparked the imagination of Israel’s team and architect Steve Clem, AIA, ASID, IIDA, a principal of tvsdesign in Atlanta. They designed custom hanging fixtures that not only uplight the structure, provide general ambient downlighting, and selectively accent the furniture, but also incorporate occupancy and daylight sensors.
Clem says the lighting scheme had to highlight the furniture without creating glare in the offices and conference rooms that share the space. He and Israel designed custom fixtures with fluorescent lamps that provide uplighting and downlighting, plus infrared halogen MR-16 lamps that can be dimmed or brightened to accent specific furniture pieces.
The new showroom is the first LEED-CI Platinum project in Los Angeles and exceeds Title 24 California Building Code requirements by more than 30%.
SIDEBAR: Target Beams in on Energy Savings
As part of a remodeling program to expand its fresh-food offerings, Target Corp. is implementing LED lighting on a large scale. New and existing refrigerated cases will feature LED display lighting that performs well in cold environments, says Target spokesperson Jenna Reck.
Older fluorescent T8 bulbs used previously lasted about 18-24 months, while LEDs can last up to 10 years, Reck says. The new lighting is expected to cut energy use by as much as 60%. Target will realize additional savings from the integration of motion-activated occupancy sensors in most of the display cases.
Target has used LEDs in exterior signage and has a large-scale LED display outside its corporate headquarters in Minneapolis, but this is one of the first times the company has used LEDs consistently inside its stores, says Reck. While the upfront cost may be significant, “in the long term—both from an energy efficiency and maintenance perspective—it’s really an efficient option for Target,” she says.
The company is also replacing many four-lamp fluorescent ceiling fixtures with two-lamp fixtures to save energy without sacrificing the quality of light throughout the store.