According to the Office Building Energy Use Profile report from the Environmental Protection Agency (EPA), space conditioning and lighting account for 70 percent of all energy consumed in a typical office building with an additional 20 percent of energy consumption used to power office equipment. Water heating, cooking, refrigeration systems and other miscellaneous uses consume the remaining energy. The report estimated that as much as 30 percent of the energy consumed in office buildings is wasted. Implementing energy-efficiency lighting measures, such as using high performance light sources, occupancy sensors and perimeter daylighting controls, results in savings during the workday with those more efficient technologies, and overnight with lighting controls. By being knowledgeable about office lighting sources, ballasts, fixtures and controls, the electrical contractor can demonstrate to the office building owner how implementation will save money and energy as well as enhance the offices’ aesthetics and worker productivity.
With today’s pervasive concerns about energy consumption, lighting manufacturers are focusing on providing more high-efficiency lighting sources for office applications. Fluorescent lighting still is used most often in office applications, and the newer T5 fluorescent lights have even higher efficacy than T8 lamps, particularly when combined with programmable start ballasts.
“Light sources today are driving watts-per-square foot down to lower levels. And the use of occupancy sensors in conjunction with new programmed start ballast technology in private offices preserves the fluorescent lamp’s life longer,” said Steve Lydecker, vice president of commercial fluorescent lighting for Lithonia Lighting, Conyers, Ga., an Acuity Brands company.
Lamps are, of course, controlled by ballasts. When electronic ballasts were introduced in the industry more than 20 years ago, they showed promise of gains in electrical efficiency that these products delivered. As the technology has continued to evolve, high-efficiency fixed output electronic ballasts have gained in popularity, according to Stuart Berjansky, senior product manager, controllable lighting, Advance Transformer Co., Rosemont, Ill.
“These ballasts help reduce the losses of the lamp/ballast system and deliver an overall higher efficiency system, which can reduce total system wattage by more than 45 percent relative to the much older T12 fluorescent systems, driven by magnetic ballasts, and by as much as 30 percent relative to the use of conventional T8 lamps and electronic ballasts,” he said.
Energy savings can further be improved through the use of dimming ballasts. Continuous dimming ballasts can maximize energy savings and provide fluorescent lamp dimming from as low as 1 percent output all the way to full output, while step dimming ballasts enable light output at fixed, preprogrammed steps.
“Electrical contractors can work with the office lighting designer to consider the total cost of ownership over the life of the system and not just the up-front capital cost in determining which system is best for the project,” Berjansky said.
Advanced lamp sources and ballasts require innovative fixtures to improve both energy consumption and office aesthetics. Since the 1990s, the modern office has tried to eliminate glare from high-angle lights, according to Lydecker. Now that computer monitors have evolved to reduce the effect of reflected light, the industry has developed volumetric fixtures that illuminate both vertical and horizontal surfaces and provide a better sense of the architecture and space in the office.
According to a paper by Kevin Leadford, principal engineer at Lithonia, volumetric lighting refers simply to lighting that is less directional and more uniform throughout the entire space. It extends beyond the workspace to illuminate adequately the entirety of the interior, resulting in the office feeling brighter, larger, more public and more relaxing.
Managing lighting is the latest industry innovation, according to Michael Jouaneh, marketing manager, Lutron Electronics Co. Inc., Coopersburg, Pa.
“In the recent past, office light fixtures were static, individual entities that didn’t communicate with each other or with other building systems and only turned off or on with a standard switch or with the help of a time clock or occupancy sensor,” he said.
In today’s digital age, office lighting fixtures can listen and talk to each other and to environmental and daylighting sensors through digital addressable dimming ballasts. This enables them to become dynamic entities that are networked with sensors, controls, window shades, building management systems, and with each other for maximum energy efficiency, productivity, and comfort. Digital addressable ballasts and software allow the office facility manager to control, monitor, analyze and report on the lights for an entire building or office campus. Additionally, natural light can be managed through the use of automated window shades, which can be automatically raised or lowered to reduce solar heat gain and sun glare while improving office occupants’ comfort.
“Today’s new lighting controls, sensors, ballasts and automated shades provide a total light management solution,” Jouaneh said.
Renovation opportunities in office lighting applications also are on the rise, according to Lydecker.
“Renovation has typically centered on replacing lamps or ballasts to increase efficiency. Today, however, more office building owners want total fixture replacement as part of the renovation to take advantage of volumetric light technology and increased efficiency,” he said.
With the slowdown in new construction, renovation projects provide growth opportunities for electrical contractors and enable them to demonstrate how the latest lighting technology lowers operating cost, increases efficiency and provides improved environments for employees.
Technology and office lighting design
Since some of the newer fixtures can cover more square footage with light, the office lighting design requires less hardware, providing the electrical contractor with a simpler installation and the owner with overall lower installed and maintenance costs.
“Using fewer resources to gain adequate illumination at wider spacing is a more sustainable design solution,” Lydecker said.
Other sustainability initiatives, such as Leadership in Energy and Environmental Design (LEED) for Existing Buildings (EB), which addresses whole-building cleaning and maintenance issues (including chemical use), recycling programs, exterior maintenance programs, and systems upgrades, enable designers to do more with less and to take the energy required to light a space from 1.1 watts per square foot to as low as 0.6 watts. Sustainable design requires using more energy-efficient systems and longer life lighting products, the integration of daylight and a focus on the people occupying the office space, and the use of controls to tie lights and other LEED criteria-compliant energy savings materials and systems together.
The current strategy in sustainable office lighting design is, task-ambient lighting systems that use indirect or direct/indirect lighting and supplemental LED task lighting that is tied to daylight sensing, according to Susan Anderson, manager of energy relations for Osram Sylvania, Danvers, Mass.
“A task-ambient lighting approach to design reduces the general light levels and incorporates personal control of supplemental task lighting provided by energy-efficient lights,” she said.
Daylight harvesting is another key sustainability trend of which more building owners are taking advantage.
“Daylight harvesting allows innovative architectural design of the office space and enables the use of more sophisticated skylights and windows that can push more light into the interior and allow light sources to be dimmed to conserve energy,” said Mary Beth Gotti, manager of the GE Lighting and Electrical Institute, Cleveland. Besides, she said, people appreciate natural light, which can translate into increased productivity.
Today’s lighting technology allows designers to be more flexible in meeting the needs of a variety of environments and promoting a more comfortable, tailored environment for the office worker. Occupancy and motion sensors are particularly effective in small private offices that are unoccupied for long periods of time.
“Electrical contractors and designers must be careful when deciding which spaces actually require occupancy and motion sensors,” Gotti said.
These devices, however, have evolved to become intelligent and capable of learning usage patterns within the space.
“As more buildings become green and achieve LEED certification, sensors and daylight harvesting will become increasingly prevalent in offices because it truly enables building managers to maximize energy savings within a facility,” Berjansky said.
The next generation
It is expected that the next shift in office lighting will be in innovative white LED solutions for general illumination applications, such as cove lighting, perimeter lighting solutions, task lighting and integrated furniture lighting.
“White LEDs are still more expensive than conventional platforms, but they are expected to continue to evolve and mature to more cost-competitively provide better color rendition and a better value proposition,” Gotti said, adding that organic LEDs (OLEDs) are also being developed and are expected to provide a more soft and diffused light and may challenge some of the fluorescent applications in offices today.
Lydecker predicts more sustainable and efficient technologies will be developed for offices to drive down costs.
“The industry has always focused on improving technology and providing durable products that advance efficiency and higher quality, lower life cycle costs, and provide better visualization experiences for office workers,” Lydecker said.
According to Anderson, contractors should expect more prebid and construction conferences because of increasing system complexity and integration.
“Contractors should also expect to see commissioning requirements in bid documents that require testing light systems’ interoperability and performance to ensure that the solution is yielding the energy savings it is designed to deliver,” she said.
In the future, lighting systems will become increasingly integrated within the complete building, requiring the contractor to have a solid understanding of the ways in which these technologies interact and where the industry is headed in order to secure the company’s position, Berjansky said.
“The contractor’s ability to be application-oriented and to truly understand the needs of all parties involved will be invaluable,” Berjansky said.
By combining the use of sophisticated digital addressable ballasts, high-efficiency lighting sources and fixtures, lighting controls, occupancy and motion sensors, and daylight harvesting technologies, electrical contractors can help office building owners save 60 percent or more in office lighting energy. The result is good for everyone: the office worker, the building owner, the contractor and the planet.
BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 or firstname.lastname@example.org.