Electric lighting has revolutionized the way we live, work and play. According to The Need Project, lighting accounts for about 25 percent of the average home’s electric bill, while, on average, the commercial sector uses approximately 60 percent of its electricity for lighting. And, according to the Department of Energy (DOE), almost half of the energy used in the United States today is for lighting.
Many factors contribute to the energy consumed through a building’s lighting, including the type and efficiency of the lights used, the design of the lighting system, and the lighting controls used. The amount of energy consumed through lighting also can vary by the type of the commercial building. It can account for as little as 15 percent in food-service buildings or as high as 30 percent for retail and service buildings. The commercial sector offers a unique set of opportunities and challenges for energy management with potential savings ranging from 15 to 30 percent of usage.
Most commercial buildings have converted from incandescent to fluorescent lighting, which uses much less energy to produce the same amount of light and can lower long-term lighting costs by as much as 50 percent. In addition, compact fluorescent lamps (CFLs) have made inroads into both residential and commercial lighting systems in the last few years, as they are very long-lived and produce significant savings over the life of the bulb.
Additional lighting technologies also enable electrical contractors to provide customers and end-users with opportunities to better manage their building’s energy consumption, depending on the specific application.
Light emitting diodes (LEDs), commonly used in exit and other signage in and around a building, consume less energy, have a very long life and are less expensive to maintain. White LEDs are expected to overcome issues with color rendering and light output and be used in general illumination applications within the next few years. Expectations are that by 2030, 20 percent of the total lighting market will be LED-based.
Electronic ballasts with dimming controls can lower lighting operating expenses and enable a significant energy consumption reduction by using fewer fixtures in new construction applications or lower-wattage lamps in retrofits. Occupancy and motion sensors reduce light usage and consumption in unoccupied spaces, while daylight harvesting enables building managers to use digital photo sensors to detect daylight levels and automatically adjust the output level of electric lighting.
Energy-efficient lighting can lead to better building energy management. Lighting controls and programmable dimming systems, such as Digital Addressable Lighting Interface (DALI) technology, also are essential. DALI is a dedicated protocol purely for lighting control. It is effective for setting scenes and for getting feedback concerning faulty light sources. According to DALI-AG, this makes the technology useful for tying lighting controls into building automation systems where remote supervising and service reports are required.
Other strategies that minimize a building’s energy requirements include specifying illumination requirements for each given area of use, analyzing lighting quality to ensure that issues such as glare or incorrect color spectrums are not biasing the design, integrating space planning and interior architecture to lighting design, selecting fixture and lamp types to reflect the best available technology for energy conservation, maintaining lighting systems to minimize energy waste, and training building occupants to use lighting equipment in the most efficient manner.
The Energy Policy Act (EPAct) established a number of tax deductions for either new or retrofit construction of commercial or residential multirise buildings that are designed to achieve 50 percent energy cost savings relative to the requirements outlined in ASHRAE Standard 90.1-2001. In December 2006, the EPAct tax credits were extended to include the installation of qualifying technologies between Jan. 1, 2006, and Dec. 31, 2008. Under the law, building owners are encouraged to focus first on lighting systems because of their ease and availability of upgrades and because of the known achievements in energy efficiency that are gained through more efficient lighting.
Until the Treasury Department issues final regulations defining savings targets for individual building systems, the Commercial Buildings Deduction’s Interim Rules for Lighting Systems are in effect. The rules offer an accelerated tax deduction that is the lesser of either the complete cost of installing energy-efficient interior lighting, or 30 to 60 cents per square foot proportional to lighting power density savings of 25 to 40 percent of ASHRAE 90.1-2001. In addition, the rules require bilevel switching, which is considered a simple controls addition that can reduce power input by up to 15 percent on an annual basis.
These provisions for lighting in the EPAct represent a strong incentive for building owners to reduce operating costs and invest in available, proven, energy-efficient lighting choices that better manage building energy use.
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.