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Energy Savings: Lighting

  1. Three simple and effective light savers
    There are three ways in which lighting energy use can be reduced by building owners: implement a greater degree of control over the use of lighting, use more efficient lighting equipment and apply better lighting system design strategies. Translated into a general guide, the goals statement for a comprehensive lighting energy conservation program should read: turn it off when it isn't needed; use the most efficient, suitable equipment; and provide light only where it is needed.

  2. A good lighting design is worth the investment.
    When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.

  3. Balance ballast costs with bulb life cost savings.
    Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

  4. Consider a T8 system retrofit
    Even if you have already retrofitted a lighting system with energy-efficient core-coil ballasts and "watt miser" lamps, you can get further savings with a T8 conversion. The T8 system is, in most cases, the best retrofit method for existing fluorescent lamps. T8 lamps and ballasts are much more efficient than standard lamps and ballasts and their use creates an opportunity for delamping by astute use of reflectors, new lenses and "overdriven" ballasts. Often, existing four-lamp fixtures can be retrofitted with three or even two T8 lamps and ballasts and still maintain the same light output. Fixtures that have state-of-the-art lamps or ballasts (T8 lamps, electronic ballasts, etc.) may save plenty of energy but may also require a higher premium at relamping or reballasting time. Much of this cost is offset because of the longer life. This longer life not only cuts down on replacement component costs but also reduces the associated labor expense to replace them.

  5. Consider dimming systems
    Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox-mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

  6. Consider motion detectors
    Incorporate motion detectors where they make sense. Suppose that you have fixtures with U-shaped fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). If you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three-hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 1/2 years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

  7. Consider the cost of energy when retrofitting lighting systems
    When considering lighting system retrofits; remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses.

  8. Distribute daylight evenly.
    Employ special strategies to help distribute daylight evenly in multiple-story buildings. Simply enlarging window openings in such structures does not solve the problem. This is because near the ground level, some daylight bounces off the landscaping and streetscaping to balance the light from the sky. In high-rise buildings, you can achieve balance artificially by using reflectors and diffusers built into the glass.

  9. Every facility is different.
    When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

  10. Exit signs can be a fast way to cut costs.
    Replace your 10, or 20 watt incandescent lamps in exit signs with 5 watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two lamp 15 watt incandescent sign with two, 5 watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LFD and electroluminescent exit light fixtures can be an effective alternative to CFLs.

  11. Fluorescent light dimming systems can save big.
    Full-range and "step" fluorescent dimming systems can significantly reduce the power delivered to fluorescent lights and can even be activated in response to available daylight for perimeter areas. While fluorescent control systems can be costly, the potential savings are great. A simple wallbox mounted occupancy sensor (infrared or motion detector) can save a significant amount of money.

  12. Improve your lighting control
    Lighting control is perhaps the most important element of any lighting energy conservation program. Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time-based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

  13. In lighting systems, one size does not fit all.
    When incorporating energy-efficient lighting technologies, it's important to remember that every facility is different. Without careful thought as to which are best suited for your particular application, you will not achieve the best rate of return on your energy conservation investment. In some applications, it will make sense to replace the entire incandescent fixture with a fluorescent one. In others, it is better to simply replace the incandescent lamp with a compact fluorescent lamp.

  14. Incorporate motion detectors where they make sense.
    Suppose that you have fixtures with U-Shaped 'fluorescent lamps normally rated at 18,000 hours of life (at 12 hours per start). If you use the fixtures every day of the week for 12 hours each day, the lamps should last approximately four years before they burn out. Let's say you determine that the offices are only used for two three hour periods each day. You decide to install motion detectors in these spaces. Now, at three hours per start, the life of these lamps is reduced to 12,000 hours. Even so, because of the reduced usage, they will last about 5 ½ years before they burn out. You have extended the time between relamping by 1 1/2 years (37.5 percent) and consequently lowered your maintenance costs. You have cut down your energy bill by 50 percent at the same time.

  15. Increase natural light
    Increasing the amount of natural light used in your facilities dramatically lowers your utility bills. The more artificial lighting used, the greater the heat load imposed on the air conditioning system. This is a critical point because artificial lighting and air conditioning consume the largest amount of electrical energy in a typical commercial building.

  16. Lighting control systems are a good long-term investment.
    Lighting control is perhaps the most important element of any lighting energy conservation program Its benefits are concrete, measurable and, in most cases, quickly realized. Many lighting control projects have payback periods of less than one year. On/off controls are most suitable for applications where lighting is not needed for extended periods of time, but where manual switches might be left on. The choice between occupancy sensors and time based controls should be based on the nature of the operation being performed in the affected space. For example, hallway lighting in office buildings is generally needed only during scheduled hours and therefore well-suited for time-based controls. If lighting is needed on a more random basis, such as private offices, occupancy sensors provide a better level of control and greater energy savings. Daylighting control systems examine the total amount of light available in a given space and switch off one or more banks of lights whenever enough sunlight is available. Daylighting control systems are particularly well suited for use in facilities with large areas of exterior glass.

  17. Look into a T8 lamp conversion.
    Even if you have already retrofitted a lighting system with energy efficient core coil ballasts and "watt miser" lamps, you can get further savings with a conversion to T8 lamps.

  18. Replace exit signs
    Replace your 10-, 15-, or 20-watt incandescent lamps in exit signs with 5- or 7-watt compact fluorescents (CFLs). While the incremental energy savings may seem small, the continual operation of exit signs makes the retrofit very cost effective. Retrofitting a two-lamp 15-watt incandescent sign with two, 5-watt CFLs will save approximately 175 watts, or about $15 per year. The cost of retrofit kits may be covered by utility rebates, resulting in a very quick payback. These savings are dwarfed in comparison to the maintenance savings from fewer lamp changes. A typical incandescent exit sign lamp needs to be changed every two months; a CFL needs to be replaced less than once a year. (And some fluorescent retrofit kits have two lamps which operate in tandem, thereby reducing by half the number of trips up the ladder to change a lamp.) Assuming 20 minutes per lamp change, you can save about two hours of labor per year per exit sign by converting to fluorescent. In a building with 100 exit signs, this results in a maintenance savings of five weeks labor time per year. LED and electroluminescent exit light fixtures can also be an effective alternative to CFLs.

  19. Replace incandescent lamps with compact fluorescents.
    It's a good idea to replace incandescent lamps with compact fluorescents (CFLs). When doing so, the proper ratio is about 3 1/2% incandescent watts to 1 compact fluorescent watt. There may be an aesthetic problem with replacing incandescent lamps with CFLs in "can" fixtures because these fixtures are not designed for CFLs. The lamps often protrude from the bottom of the fixture and the light distribution from the fixture is poor because its optical characteristics suit an incandescent lamp. Another approach: retrofit with a specially designed reflector and lamp holder that maximizes the optics of the CFL and has a more pleasing appearance.

  20. Replace inside and outside mercury lamps.
    Get rid of mercury lamps inside and outside a building. Their light output reduces over time, and a dim mercury lamp uses as much energy as a brand new one. Replace them with high-pressure sodium or metal halide lamps.

  21. The lowest cost lighting isn't usually the lowest purchase price.
    Do not let cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to run. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, and if you can tap into utility rebates and other incentives.

  22. Update a system using energy core-coil ballasts and "watt miser" lamps to a T8 system for further savings.
    Update a system using energy core-coil ballasts and "watt miser" lamps to a T8 system for further savings.

  23. Use task lighting where possible
    When retrofitting an existing lighting system, look at the task being performed in the space. In many cases, high overall light levels can be reduced when good task lighting is installed. A combination of good, sensible lighting design with the use of the latest technology lighting systems can result in substantial energy savings and an overall improvement in lighting quality.

Outdoor Lighting:

  1. Build Your Own Conservation Program.
    There are three ways in which lighting energy use can be reduced by building owners: implement a greater degree of control over the use of lighting, use more efficient lighting equipment and apply better lighting system design strategies. Translated into a general guide, the goals statement for a comprehensive lighting energy conservation program should read: turn it off when it isn't needed; use the most efficient, suitable equipment; and provide light only where it is needed.

  2. Consider the cost of energy when retrofitting lighting systems. When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses.

  3. Don't Think About First Cost Only! Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to operate. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, especially if there are utility rebates and other incentives.

  4. Replace inside and outside mercury lamps. Get rid of mercury lamps inside and outside a building. Their light output reduces over time, and a dim mercury lamp uses as much energy as a brand new one. Replace them with high-pressure sodium or metal halide lamps.

  5. Replace . Get rid of all mercury lamps inside or outside the building! Replace with high-pressure sodium (HPS) or metal halide lamps. These lamps have a higher efficacy (efficiency) than mercury lamps. A 400-watt mercury lamp is rated at about 47 lumens/watt, whereas the same size metal halide lamp is rated at 64 lumens/watt and a similar HPS lamp is rated at 112 lumens/watt. Also, mercury lamps have extremely long lives, but light output reduces drastically as lamps get older. A dim mercury lamp costs as much in energy as a brand new one to operate.

  6. The lowest cost lighting isn’t usually the lowest purchase price. Don't let first cost deter you from investigating some of the more energy-efficient lighting technologies. The most expensive lighting equipment usually consumes the least energy and therefore costs much less to run. The initial cost of a state-of-the-art system may even be lower than the overall cost of a less expensive and less efficient system if you use fewer fixtures to achieve the same or better light levels, and if you can tap into utility rebates and other incentives.

  7. Use life-cycle costs to make decisions. When considering lighting system retrofits, remember that the least expensive part of the system on a life-cycle basis is the fixture and lamp. The most expensive component is the energy that the system uses. That is why fluorescent lamps are usually much less expensive over the life of the lamp than incandescent.