The workhorse in indoor commercial applications has been the linear fluorescent lamp, but vastly more efficient alternatives are slowly, steadily putting that horse out to pasture.
The Department of Energy (DOE) estimated that lighting systems using linear fluorescent lamps account for over 75% of the lighting service in commercial buildings, with the total number of installed fluorescent luminaires in the U.S. estimated at over 960 million units.
“Troffers are roughly 50% of all commercial light fixtures. They’re the most ubiquitous fixture you have,” says Michael Myer, of the Energy and Environment Directorate for the Pacific Northwest National Laboratory (PNNL). “It’s pretty much a guarantee: every building has at least one, and most have a lot.”
While lighting solutions have become more efficient over the years, adoption and implementation of new technologies are still lagging. Although the installation of LED troffer-style luminaires jumped from an estimated 40,000 units in 2010 to nearly 700,000 units in 2012, LEDs still represent less than 0.1% of the installed troffer luminaires in commercial buildings, according to Mary Yamada and Dan Chwastyk, authors of the report, “Adoption of Light-Emitting Diodes in Common Lighting Applications.”
“LEDs have surpassed many conventional lighting technologies in terms of energy efficiency, lifetime, versatility and color quality. Due to their increasing cost competitiveness, they are beginning to successfully compete in a variety of lighting applications,” the authors note. “It is forecasted that LED lighting will represent over 75% of all lighting sales by 2030, resulting in an annual primary energy savings of 3.4 quads.”
Additionally, Yamada and Chwastyk conclude that it may be possible to achieve over 25% energy savings on a national level if LED technology reaches its projected market penetration in troffer luminaires of over 65% by 2030.
As such, building owners and facility managers can significantly reduce their energy costs by retrofitting troffer lighting to more efficient fixtures. The key to a successful lighting fit-out is to assess the existing facility’s needs, evaluate available options, and calculate all costs prior to undertaking a lighting upgrade.
Assess Needs and Options
“First survey what you have and determine what you need,” Myer explains. “If you’re using an outdated T12—and, shockingly, there are still a lot of T12s out there—then that’s a slam dunk retrofit opportunity.”
He adds that if a building is over-lit or using bad fluorescent optics like egg crates, that is another no-brainer opportunity because the number of lamps used to light the space can often be cut in half. “You should be able to cut down on your output because egg crate louvers are only 50% efficient, so you’re losing a lot right there,” he says.
Tubular LEDs (TLEDs) are an easy retrofitting option because many work directly with the inline ballast, and upgrading inefficient fixtures is as simple as changing a bulb. Also known as UL Type A TLEDs, these products have the benefit of the easiest installation, with no electrical or structural modifications needed.
However, some manufacturers and energy service companies (ESCOs) warn that if the age or manufacturer of the existing ballast isn’t known, TLEDs aren’t recommended. Not all TLEDs are compatible with existing ballasts, which may fail, creating long-term maintenance and warranty issues that owners and FMs want to avoid. Additionally, a UL Type A tube sacrifices efficiency due to the additional power loss from the existing ballast and is limited in dimming and controllability, according to Myers.
Replacing all of the ballasts is another option, but it comes at a much greater cost, of course. Alternatively, UL Type B TLEDs can be hard wired directly into electrical leads, bypassing the ballast which eliminates the compatibility issue. Type B TLEDs are more efficient than Type As, with no power loss resulting from removing the existing LFL ballast, but are also limited by control and dimming capabilities. Also, as Myers notes, facility professionals that choose this course of action have now created an electrical scenario to which they are committed.
As a result of these challenges, Myers believes troffer retrofit kits are the most promising solution for lighting upgrades in existing facilities.
“Kits are the sweet spot,” he says. “I’ve seen a lot of manufacturers advertise the speed and efficiency when installing their kit. I think they’re the future because they reduce labor time by not needing to change out the fixture, yet you reap all the benefits of better thermal management, better optics and fewer electrical interactions to manage,” he explains.
Myers adds that the up-front and installation costs are often half of those for a new luminaire, and retrofit troffer kits are also control-ready.
Count the Costs
Part of the difficulty in estimating overall savings with lighting upgrades is the many variables to consider, and each project is case-specific. With that in mind, and using a national baseline cost of 10 cents per kWh, Myers estimates the potential energy savings realized by converting to TLEDs or retrofit kits (along with controls) in the neighborhood of 30-50%. However, he cautions facility professionals against selecting a lighting solution based solely on wattage rather than lighting needs.
“Some people are not providing adequate light. They’re just looking at the wattage, and they’re thinking, ‘Well, this product draws this many watts. That’s all I want,’” he says. “They’re not actually saying, ‘Well, how efficient is it? Am I getting the right amount of light?’”
TLEDs are the lowest-cost equipment option, followed by kits, then troffers. Labor is often the item that inflates costs the most. “Depending on where you’re located – especially if you’re in an earthquake area – it’s not only the electrical component, but a structural one because you must tie off three or four corners of a troffer to a structural member,” he notes. “It’s not just electrical labor.”
In terms of return on investment, the numbers are again very case-specific (see case studies for examples). Some organizations have recouped their investments with retrofit kits in as few as five years. Some large-scale TLED installations have been paid back within eight years, while other full troffer installations have had longer paybacks, Myers says.
When you have narrowed down your options, test them in place. Don’t rely only on manufacturer data or choose based on what seems comparable to the existing lighting. “You may not like the color of a certain bulb or see some flicker,” he warns.
For standard fixtures, he recommends doing at least a single mock-up, while a retrofit kit requires two or more. This ensures that an accurate baseline can be established to determine how long it will actually take to retrofit a facility as opposed to manufacturers’ estimates. For TLEDs, Myers suggests conducting multiple tests before committing to a purchase.
“Make sure TLEDs are installed in a couple different places. You’re going to have some variety in types of optics. Not all TLEDs are going to behave the same way,” he adds.
Because at the end of the day, the last thing any building owner or facility manager wants is to get halfway through a lighting upgrade and discover what looked good on paper turned out to be a poor choice in the field.