Lighting: Energy Efficiency Opportunities

Upgraded lighting can save money through reduced energy use, and result in increased occupant comfort and sales. The most efficient light is the light not used.

Lighting consumes 25 – 30% of energy in commercial buildings, and is a primary source of heat gain and waste heat. Excess heat and energy can be reduced by implementing an energy-efficient lighting system. Upgraded lighting systems can also improve lighting quality to increase occupant comfort and productivity.

Benefits of a comprehensive lighting upgrade:

• Highly profitable energy savings and low-risk investment.
• Maximize energy savings opportunities for subsequent building systems upgrades.
• Successful lighting upgrades can increase management and occupant acceptance of other energy-efficiency projects.

A comprehensive lighting upgrade achieves your qualitative lighting objectives while maximizing efficiency and profitability. With rewards beyond the sum of its parts, this process integrates equipment replacement with deliberate design, operation, maintenance, and disposal practices. This whole-system approach takes what is frequently regarded as a complex system of individual decisions and unites them into a strategic approach that ensures that each opportunity is addressed and balanced with other objectives.

Avoid implementing only the easiest and quickest payback opportunities. While this may seem appealing, you will forgo quality-enhancing and savings opportunities that result from comprehensive upgrades. A simplified upgrade may yield faster payback, but you will sacrifice long term energy savings over the life of the system.

High-quality lighting design includes a comprehensive lighting analysis and the coordinated selection of lighting, fixtures, fixture placement, controls and room finishes (e.g., high reflectivity paint) to result in improved lighting quality and reduced energy use. To achieve the best quality and efficiency from any new lighting system you install, it is best to consult a lighting professional with experience in energy efficiency. And that’s Empower Energy. Contact us to day and we’ll show you how to start saving money through reduced energy use in your lighting. Call Mark Bell at 404.681.3270 or email at mbell@empoweret.com.

Read more on Lighting Efficiency – click here.

Too often, lighting retrofits start and finish with the objective of pairing lamps with ballasts to turn electricity into visible light most efficiently. While the majority of energy savings potential often resides here, pursuit of high efficiency alone may lead to compromises in light quality and controllability and higher system installation and maintenance costs. Lamp and ballast specification should seek to optimize efficiency while maintaining a balance with these other considerations.

While a wide range of light sources are available, the predominant types used in commercial and industrial spaces are fluorescent and high-intensity discharge (HID). Historically, fluorescent lighting has been used for high-quality, general-purpose indoor diffuse lighting. HID has been used for industrial and outside lighting. However, technical advances and a flood of new products have increased the use of HID in interiors.

Although fluorescent sources are still limited by their inability to function in very hot or cold environments or as spotlights, advances in physical size, thermal performance, and light quality are allowing wider application in industrial, manufacturing, and residential environments. Likewise, in the past, HIDs have typically been limited by their high light output and their inability to render color accurately or to be switched on and off frequently or dimmed. Today, however, HID lamps are used indoors in some applications where light quality is critical and where dimming and lower light outputs are necessary. While practical limitations still exist, now, more than ever, specifiers need to research lamp capabilities and understand the tradeoffs between efficiency and performance. For example, linear T5 lamps, which have recently been introduced, are becoming popular in direct/indirect pendent mounted systems, cove lighting and retail display lighting. But should not be used in retrofit applications because of the following limitations:

• Available only in metric lengths
• Lamp holder design is different that T8 and T12
• Higher tube luminance, which will cause glare problems in existing lighting equipment.

Ballast selection is integral to lamp performance. All fluorescent and HID lamps require a ballast to provide the necessary starting voltage and regulate lamp current and power quality. Ballasts determine the lamp’s light output, life, and control capabilities. Similar to advances in lamp technology, electronics advances have greatly expanded ballast capabilities and selection.

The three types of fluorescent ballasts are magnetic, electronic, and hybrid ballasts. Magnetic ballasts, also known as electromagnetic ballasts, have improved from the standard-efficiency, core-coil ballasts last made in 1989 to higher efficiency models. Electronic ballasts have been developed for almost all fluorescent lighting applications to replace their conventional magnetic counterparts directly. Electronic ballasts operate fluorescent lamps at a higher frequency, which improves system efficiency by about 30 percent when used in conjunction with T8 lamps to replace T12 lamps and standard magnetic ballasts. Electronic ballasts also offer these advantages:

• Less audible noise and virtually no lamp flicker.
• Dimming capability (with specific ballast models).
• Ability to power up to four lamps, increasing energy efficiency by an additional 8 percent, while reducing first cost and maintenance costs.

Hybrid ballasts, which combine features of magnetic and electronic ballasts, are also available. Although these ballasts offer the same efficiency benefits as electronic ballasts, they cannot power more than three lamps.

Instant-start circuitry offers an additional 5 percent efficiency compared with rapid-start electronic ballasts. However, if lamps are frequently switched on and off, additional lamp and maintenance costs may exceed energy savings.

Programmed-start ballasts offer increased lamp life compared to instant or rapid start ballasts. Programmed-start ballasts are designed to soft start the lamp, which decreases lamp cathode damage. luminaires are switched on and off frequently, such as in spaces controlled by an occupancy sensor.

Selecting ballasts for HID lamps involves matching a ballast type to the electrical distribution system in your building to control the lamp light output when line voltage varies. The level of this control is then balanced against ballast losses, power factor, lamp life, and cost. lamps, these ballasts are becoming more popular because of their smaller size, weight, decreased lamp color shifting, and increased compatibility with lighting controls Nominal efficiency improvements of only 5 to 7 percent make retrofits difficult to justify on energy savings alone. Linear reactor circuit ballasts have been developed which, when used with matched, pulse-start, metal halide lamps, can cut ballast losses in half and offer a 20-percent improvement in efficiency.

Successful lighting design begins with an assessment of several design issues to meet the occupants’ lighting needs, which depend on the tasks performed in the workspace. The lighting system should be designed to provide the quantity and quality of light responsive to those requirements. Several issues that should be considered are color, daylight availability, glare and light distribution. Retrofits that skip this assessment may perpetuate designs that have become inadequate because of workspace rearrangements or changing tasks.

It is important to recognize that people do not see absolute levels of illuminance, the amount of light shining on a surface. They see differences in luminance or brightness—the amount of light reflected back from the surface. The fundamental relationship between lighting and occupant tasks makes it essential that the lighting, task, and surrounding area be evaluated together. Although lighting retrofits are generally limited to the lighting equipment, good design should evaluate and modify work environments where appropriate. For example, a lighting redesign may reorient computer monitors away from windows or increase the contrast between tasks and their backgrounds.

Room dimensions and finishes also affect the required light output and thus the energy consumption of all interior lighting systems. As much as one-third of the energy use of a lighting system depends upon the surrounding interior features, such as the ceiling height, windows, and color and reflectivity of room surfaces and furnishings. Where possible, ensure that features that significantly enhance lighting levels, such as large windows and light-colored finishes, are utilized wherever possible. This helps minimize the required light output and therefore the energy consumption of the lighting system.

The same principals and guidance that apply to interior lighting are applicable to exterior lighting as well. Outdoor lighting that is designed and implemented properly should be cost effective, control light by directing it where needed; reduce glare and distribute illumination evenly; and reduce light trespass.

A lighting upgrade will most likely require the removal and disposal of lamps and ballasts. Group relamping every several years, and occasional spot relamping as necessary, will also create additional lamp waste. Some of this waste may be hazardous. As the waste generator, you must manage it according to applicable federal, state, and local requirements. While your specific requirements and your selected disposal options will determine the expense, it is important to note that disposal costs are rarely a “deal breaker” in a lighting upgrade. Typically, disposal costs constitute a very small percentage of the overall life-cycle costs of operating a lighting system. Investigate and budget for these disposal costs both as a first cost during the upgrade and as an ongoing operation and maintenance expense.

Many lamps contain mercury, and are therefore considered hazardous waste under the Resource Conservation and Recovery Act (RCRA). A added hazardous waste lamps to the universal waste program. universal waste lamps include fluorescent, high intensity discharge, neon, mercury vapor, high pressure sodium, and metal halide lamps. Visit EPA’s online RCRA Web site at www.epa.gov/rcraonline/ for more details. Recycling spent mercury-containing lamps is an alternative disposal method. The National Electrical Manufacturer’s Association (NEMA) encourages this practice and offers information on a website www.lamprecycle.org designed specifically to address lamp recycling issues.

The proper method for disposing of used ballasts depends on several factors, such as the type and condition of the ballasts. Generally, ballasts manufactured after 1978 contain the statement “No PCBs” and have not been found to contain PCBs. The disposal of Polychlorinated biphenyls (PCBs) is regulated under the Toxic Substances Control Act (TSCA). nformation regarding the disposal of PCBs can be found on the PCB Home Page at www.epa.gov/pcb. Additional information can be obtained from the TSCA Hotline, which is reachable by phone at (202) 554-1401 or by e-mail at tsa-hotline@epa.gov.  Other factors controlling the disposal of ballasts will depend on the regulations and recommendations in effect in the state(s) where you remove or discard them.  Check with regional, state or local authorities for all applicable regulations in your area.

If you generated lighting material wastes, you are responsible for managing its disposal according to federal, state, and local laws or requirements.

The three main considerations for exterior lighting are energy waste, glare, and light trespass. Light trespass, also known as spill light, is light that strays from its intended target and becomes an annoyance or nuisance. Maximizing the utilization of light output where and when it is needed will reduce light trespass. IES recommended light levels makes good economic sense and will minimize adverse environmental impacts associated with light trespass.

Strategies for Exterior Lighting

• Use lighting fixture with directional control.
• Direct and control light output to locations where it is needed.
• Use time controls/dimmers to turn lights on and off and reduce light levels.
• Design and install lighting to minimize glare.
• Use the right amount of light for the task
• Use energy efficient light sources and fixtures.

Environmental Effects

Exterior lighting can also have effects on the environment, excessive lighting near wildlife areas can adversely impact migrating bird life, nocturnal insects and other species. State and local ordinances have been established to protect natural wildlife from light pollution.

Ordinances and Community Standards

Outdoor lighting ordinances and codes encourage better quality lighting, which reduces glare, light trespass, and energy waste. Many codes are now including the concept of E-zones to distinguish between different types of lighting areas. For example, near national or state parks, wildlife refuges, or astronomical observatories lighting levels should be much lower than in city centers. The ordinances and community standards vary and local zoning departments should be contacted before implementing an outdoor lighting project.

A lighting upgrade does not end with the installation of efficient equipment. Many cost-effective opportunities for reducing energy and maintenance costs and improving occupant satisfaction are frequently missed simply because operations and maintenance issues are ignored or addressed in an ad hoc fashion after the upgrade. The following decisions need to be integrated into your upgrade design from the beginning.

All lighting systems experience a decrease in light output and efficiency over time from three factors:

• Lamp light output decreases (lamp lumen depreciation).
• Dirt accumulates on fixtures (luminaire dirt depreciation).
• Lamps burn out.

Over time, these factors can degrade a system’s efficiency by up to 60 percent wasting energy and maintenance costs and compromising safety, productivity, and building aesthetics. A planned maintenance program of group relamping and fixture cleaning at a scheduled interval minimizes this waste and maximizes system performance.

Integrating a planned maintenance program into your lighting upgrade saves money in two ways. First, you will not have to overcompensate with higher initial lighting levels to ensure adequate lighting over time. The lighting system can be rightsized, saving on annual energy use and material first costs.

Second, while replacing lamps as they burn out on a spot basis may seem like a cost-effective practice, it actually wastes valuable labor. Group relamping times the replacement of lamps at their maximum economic value, generally at about 70 percent of their calendar life. Although it means replacing lamps before they expire, group relamping dramatically reduces the time spent replacing each lamp (not to mention the time spent responding to service calls and complaints), which can reduce your overall lighting maintenance budget by more than 25 percent. In addition, planned maintenance reduces the cost of lamps through bulk-purchase discounts, the storage space needs for replacement lamps, and disruptions in the workplace.

To sustain an efficient, high-performance lighting upgrade, assemble an operations and maintenance (O&M) manual. Use it as both the lighting management policy and a central operating reference for building management and maintenance staff. This manual should include the following information:

• Facility blueprints.
• Fixture and controls schedule.
• Equipment specifications, including product cut sheets.
• Equipment and service provider sources and contacts (include utility contacts).
• Fixture cleaning and relamping schedule with service tracking log.
• Procedures for relamping, reballasting, and cleaning fixtures.
• Procedures for the adjustment of photosensors and occupancy sensors.
• Procedures for proper lamp and ballast disposal.

Review the O&M manual with the staff responsible for lighting maintenance. Make training mandatory for all new maintenance personnel. Correct operation and maintenance should be built into job descriptions and should become part of all annual performance reviews.

Reducing the connected load (wattage) of the lighting system represents only half of the potential for maximizing energy savings. The other half is minimizing the use of that load through automatic controls. Automatic controls switch or dim lighting based on time, occupancy, lighting-level strategies, or a combination of all three. In situations where lighting may be on longer than needed, left on in unoccupied areas, or used when sufficient daylight exists, you should consider installing automatic controls as a supplement or replacement for manual controls.

Time-Based Controls

The most basic controlling strategies involve time-based controls, best suited for spaces where lighting needs are predictable and predetermined. Time-based controls can be used in both indoor and outdoor situations. Common outdoor applications include automatically switching parking lot or security lighting based on the sunset and sunrise times. Typical indoor situations include switching lighting in production, manufacturing, and retail facilities that operate on fixed, predefined operating schedules. Time-based control systems for indoor lighting typically include a manual override option for situations when lighting is needed beyond the scheduled period. Simple equipment, such as mechanical and electronic timeclocks and electromechanical and electronic photocells, can be independent or part of a larger centralized energy-management system.

Occupancy-Based Controls

Occupancy-based strategies are best suited to spaces that have highly variable and unpredictable occupancy patterns. Occupancy or motion sensors are used to detect occupant motion, lighting the space only when it is occupied. For both initial and sustained success in using occupancy sensors, the sensor must be able to see the range of motion in the entire space while avoiding either on or off false triggering. This requires proper product selection, positioning, and testing.

Occupancy sensors should first be selected based on the range of body motion expected to occur throughout the entire lighted space. Controls for hallways, for example, need only be sensitive to a person walking down a narrow area, while sensors for offices need to detect smaller upper body motion, such as typing or reaching for a telephone. Once sensitivity and coverage area is established, sensors are selected from two predominant technology types.

Passive infrared sensors detect the motion of heat between vertical and horizontal fan pattern detection zones. This technology requires a direct line of sight and is more sensitive to lateral motion, but it requires larger motion as distance from the sensor increases. The coverage pattern and field of view can also be precisely controlled. It typically finds its best application in smaller spaces with a direct line of sight, warehouses, and aisles.

Ultrasonic sensors detect movement by sensing disturbances in high-frequency ultrasonic patterns. Because this technology emits ultrasonic waves that are reflected around the room surfaces, it does not require a direct line of sight, is more sensitive to motion toward and away from the sensor, and its sensitivity decreases relative to its distance from the sensor. It also does not have a definable coverage pattern or field of view. These characteristics make it suitable for use in larger enclosed areas that may have cabinets, shelving, partitions, or other obstructions. If necessary, these technologies can also be combined into one product to improve detection and reduce the likelihood of false on or off triggering.

To achieve cost-effective, user-friendly occupancy sensor installations, both types of technologies need to be carefully commissioned at installation to make sure that their position, time delay, and sensitivity are properly adjusted for the space and tasks.

Lighting Level-Based Controls

Lighting level-based strategies take advantage of any available daylight and supply only the necessary amount of electric light to provide target lighting levels. In addition to saving energy, lighting level controls can minimize overlighting and glare and help reduce electricity demand charges. The two main strategies for controlling perimeter fixtures in daylighted areas are daylight switching or daylight dimming.

Daylight switching involves switching fixtures off when the target lighting levels can be achieved by utilizing daylight. To avoid frequent cycling of the lamps and to minimize distraction to occupants, a time delay, provided by a deadband, is necessary. Several levels of switching are commonly used to provide for flexibility and a smooth transition between natural and electric lighting.

Daylight dimming involves continuously varying the electric lighting level to maintain a constant target level of illumination. Dimming systems save energy by dimming fluorescent lights down to as low as 10 to 20 percent of full output, with the added benefit of maintaining consistent lighting levels. Because HID sources cannot be frequently switched on and off, they are instead dimmed for time, occupancy, and lighting level-based control strategies.

Of equal importance to the quantity of light is the quality of light. The quality of light is dependent on both the properties of the light and how that light is delivered to the space. The fundamental quality issues include all of the IESNA “design issues“ listed in The Right Quantity of Light with special consideration given to:

• Glare
• Uniformity of luminance
• Color temperature and color rendition

The eye does not see absolute levels of illuminance; the amount of light shining on a surface. It sees differences in luminance, the amount of light reflected back from the surface. Eyestrain and fatigue are caused when the eye is forced to adapt continually to different luminances. Therefore, it is important not only to provide the right level of light but also to ensure that light is evenly distributed across the task area. Balancing light levels also ensures that task lighting levels will be adequate throughout the space. Uniformity on vertical surfaces should also be maintained to avoid a gloomy, cavelike atmosphere.

IESNA recommends as good design practice an average luminance ratio of no more than 3 to 1 for close objects and 10 to 1 for distant objects and outdoor applications (IESNA Lighting Handbook, Sect. 11—Office Lighting). In other words, the difference in light level between the task area and the background should be less than a factor of three. While some designers use illuminance variation as an organizing theme, such as defining hallways leading to open offices, or as a highlighting strategy, such as in retail and merchandising locations, large footcandle variations within a workspace should be avoided.

A common misperception contributing to the proliferation of ineffective and inefficient lighting is that more light equals higher quality light. Lighting-level requirements have evolved with the changes in our workplaces and our knowledge of visual science. The Illuminating Engineering Society of North America (IESNA) has developed consensus-based guidelines to select appropriate luminance levels for hundreds of indoor and outdoor activities. These recommendations are starting points, suggesting a range of values based on design issues, locations, and tasks. Listed below are several design issues outlined by IESNA:

• Appearance of Space and Luminaires
• Color Appearance (and Color Contrast)
• Daylighting Integration and Control
• Direct Glare
• Flicker (and Strobe)
• Light Distribution on Surfaces
• Light Distribution on Task Plane (Uniformity)
• Luminances of Room Surfaces
• Modeling of Faces and Objects
• Point(s) of Interest
• Reflected Glare
• Shadows
• Source/Task/Eye Geometry
• Sparkle/Desirable Reflected Highlights
• Surface Characteristics
• System Control and Flexibility

Lighting levels should be customized through the use of supplemental task lighting in areas requiring higher localized levels. Target lighting levels should be the sum of the ambient and task lighting levels. This task and ambient lighting design approach creates flexibility to accommodate individual tasks or worker requirements, creates visual interest, and can save considerable energy in comparison to a uniform ambient level approach.