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.
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.
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.
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.
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.
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.
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.
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.
