Lighting Efficiency: Obstacles and Opportunities
March 01, 2004
Appeared in Building Operating Management/FacilitiesNet
Now that winter is nearly over in many parts of the country, facility executives concerned with utility use will turn their attention from natural gas to electric costs. Fluctuating prices, the risk of summertime brownouts and sticker shock at the monthly energy bill all reinforce the need for improved efficiency. Lighting, perhaps the most visible use of electricity, often has been the first target for efficiency upgrades. But many facilities have upgraded lighting systems in the last decade, and some facility executives wonder just how much efficiency can be gained from another improvement.
What’s more, other building concerns compete with lighting for upgrade funding. Natural gas prices have risen breathtakingly fast, and security concerns are top-of-mind for many facility executives. As a result, lighting efficiency upgrades might get pushed out of the budget to make room for reflective roofing, long-needed HVAC retrofits or new CCTV cameras.
But facility executives should keep in mind that lighting still presents many opportunities for efficiency gains. The key is to find out how best to employ the variety of lighting options now available.
In most commercial office environments, lighting accounts for 25 to 30 percent of energy use; in offices with older technology or inefficient systems, energy use attributable to lighting can reach as high as 40 percent.
For the few remaining buildings that use T12 lamps, a switch to T8 lamps and electronic ballasts offers substantial energy savings — nearly 20 percent. But for the remainder of facilities, particularly those that use well-spaced T8 lamps with adequate accent and task lighting, one of the largest obstacles to improving lighting is the lack of a sense of urgency.
The American Council for an Energy Efficient Economy (ACEEE) recommends that “demand-side management operators increase or shift emphasis to promote new ‘super’ T8 lamps with high-efficiency ballasts” to promote improved efficiency. The savings, says ACEEE, will be in the neighborhood of 18 percent over standard T8 systems, which is comparable to the savings achieved when replacing T12 lamps with T8s.
The new premium T8 lamps are high-lumen replacements for the standard 800-series F32T8 lamps. According to manufacturer specifications, these new T8 lamps — when paired with reduced-power electronic ballasts — reduce system wattage 15 to 20 percent.
But Gary Steffy, principal at Gary Steffy Lighting Design, remains skeptical. “I might get skewered for saying this, but I’d venture that savings from standard T8 systems to the newer systems are nonexistent.”
The margin of savings, after factoring in all of the costs — including labor, first-cost for the new lamps and ballasts, disposal of the old lamps, and myriad others — strips away the savings, says Steffy. However, savings may be more significant if facility executives were planning a lighting retrofit or if there were incentives available.
But opportunities for facility executives to save money on lighting abound.
“ When owners get involved with the project from the start, there are equipment savings of 20 to 30 percent just by managing the design properly and not relying on bid engineering,” says Stefan Graf of Illuminart. “With the right lamp/ballast combinations you can achieve operational savings.”
Lighting controls are the most neglected and underused way to save money, says Steffy. “When properly used, owners can get 10 to 20 percent savings from controls.”
The concept that lighting controls help save money seems intuitive. Moreover, building codes mandate the use of lighting controls. But that doesn’t mean that facility executives use controls to full effect. Too often, control systems are overlooked, forgotten about or misprogrammed. As a result, opportunities to save money are wasted.
“ Controls are getting more complex, but they don’t have to be difficult,” says Paul Ericson, vice president of lighting design for Syska Hennessy’s Western region. He says that the simplest system is usually the best and that when full-time maintenance staff is not on site, complex programmable control systems should probably be avoided.
An effective and relatively low-tech way for many corporate environments to control lighting is via a time-programmable system. Ericson cites the system used in his firm’s San Diego offices, which switches the lights off at 6 p.m. and turns them on at 7:30 a.m. The system alerts occupants that the lights will shut off when five minutes remain on the programmable timer via a flashing light or unobtrusive audible signal.
“ All I have to do in our office if I want to stay later is walk over and push a button on a wall,” says Ericson. “The lights are programmed to stay on for another two hours.”
Similarly, if a worker arrives early, the lights can be activated at the touch of a button, each of which controls roughly 5,000 square feet of space.
While controls might be mandated by code, some regions have more stringent requirements. California’s Title 24 requires automatic control of all spaces in a building. But in other parts of the country, energy is cheaper, and mandated automatic controls are not as prevalent.
To get an accurate sense of potential energy savings, facility executives must assess the needs of their facility.
The basic components for the savings equation include the size of the lighted area and the fixtures used (or to be used) in the lighted area. The wild card is power cost.
Rate structures vary from market to market, even from hour to hour. Remember that electricity generally costs less in the winter, but lights are on longer hours. Commercial lighting systems also are operated when electricity rates peak; using an average power cost to figure savings likely will underestimate actual savings.
To obtain the most accurate estimate of savings, facility executives must use the rate schedule in effect for the facility. Although this will complicate savings calculations, it provides a better estimate of the cost effect of lighting upgrades.
An important question for facility executives is the “kind” of efficiency they seek and how it will best benefit them.
“ Lighting efficiency can be categorized in two ways,” says Graf. “There’s energy-efficient lighting and visually efficient lighting.” Visually efficient lighting, he says, offers potential savings in productivity.
Subjectively, it’s easy to agree that better lighting improves productivity. But quantifying possible gains in worker productivity is difficult at best. The argument is that satisfied workers get more done during the day and are inclined to miss fewer work days during the year. But accurately gauging productivity is difficult if not downright impossible.
Another obstacle to the use of new lighting technologies is a lack of awareness, says DeVeaux Gauger, a Leadership in Energy and Environmental Design (LEED)-accredited lighting designer at Illuminart. A recent ACEEE report backs up Gauger’s assessment. According to the ACEEE, market barriers to the adoption of energy-efficient lighting designs include, among others, a lack of awareness, concern over higher first costs of improved lighting equipment and lighting design, concerns about technology performance, and split incentives between renters and landlords in lease properties.
Facility executives are often leaders in building awareness for good lighting design. “They’re more aware of holistic design,” says Gauger. “They’ve had so many bad experiences or spent so much time and cost experimenting with bad lighting design that they value the benefits of good lighting.”
Generally, if office spaces are lit improperly, the problem is too much light. This tends to be a holdover from codes requiring light levels for the paper-based work environment that existed before computers became a standard fixture in offices; this light level is about 50 footcandles. In an underlit office space, the ambient light is usually adequate, but accent or task lighting isn’t.
Facility executives should consider revamping overhead fixtures first if there are questions about light quality. But sometimes, as Graf discovered, lighting quality has nothing to do with fixtures.
“ A shopping mall had a brightly lit food court area and adjacent hallways that seemed significantly darker,” says Graf. Skylights over the food court created strong sunlit areas, making the nearby hallways seem dark. The solution was to redirect the daylight coming in from the skylights, add accent lighting, and repaint the hallway walls a lighter shade. The updates cost the shopping mall considerably less than adding fixtures and established an equilibrium in lighting quality between the food court and hallways.
When used well, task lighting can save energy. This occurs for several reasons. For one thing, task lighting puts a smaller source of light closer to the workspace. What’s more, because some building occupants will not use their task lights all the time, it reduces the duration of the lighting used.
But too often, say designers, the correct task lighting is difficult to obtain. Steffy says it should be part of the architectural budget — only then can facility executives adequately strike the right balance between ambient and task lighting.
“ Task lights also need to have more than an on-off switch,” says Steffy. “We need more control over task lighting, like ballasts with two or three phases.”
Graf and Gauger agree. “We need to pay attention to the color quality of the lamp. There should be good distribution of light through lensing and reflectors, and there needs to be more control over task lighting,” says Gauger.
Facility executives also can get stuck with poor task lighting when it is part of the furniture budget. “With systems furniture,” says Ericson, “you often get what’s in the furniture.”
In task lighting, as with many aspects of lighting design, ensuring good design requires facility executives to be present from the start. “The key is holistic design,” says Graf. “Owners should be involved early and all the way through the process.”
Facility executives also need to be aware that good lighting design involves more than a simple one-to-one replacement of fixtures. Given today’s high-efficiency light sources, such a replacement plan will lead to overlit work environments. To compensate, fixtures should be spaced further apart.