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Lighting FAQ
How can I reduce lighting cost
 
Though the energy used by a single light is small, if you use energy-efficiency practices with all your lights, the savings can add up. To reduce your lighting costs, consider:
  • Evaluating your lighting needs (in case of an overlit facility, delamping might be appropriate).
  • Replacing T12 fluorescent lights with more energy efficient T8 lights and electronic ballasts.
  • Replacing old exit lights with new energy efficient ones that use fluorescent or LED technology.
  • Installing controls such as timers, time clocks or photocells to ensure that exterior lights are turned off at the appropriate time.
  • Replacing incandescent lights with ENERGY STAR®-qualified compact fluorescent lights that can reduce lighting costs by up to 70 percent and last up to eight times longer.

How much can I save?
Determine the percentage of your electric use that can be attributed to lighting. For most commercial facilities, lighting is responsible for 30 percent of the electric bill. If you will implement energy-efficiency practices that reduce your lighting load by half, your bill will see a cost reduction of 15 percent.
 

Can I improve?
How do I know if my building is a candidate for lighting improvements?
 
Look around. If your building has multiple incandescent lights (standard, flood, halogen) or T12 (1 1/2-inch diameter) fluorescent lights, it is probably a good candidate for a lighting retrofit. Call your utility company and ask them to conduct a free energy audit. You may discover a very attractive payback by improving your lighting system. In addition, you will have opportunity to better assess your building lighting needs and adjust them accordingly.
 

Is there financial assistance?
Yes. The Oregon Department of Energy offers a Business Energy Tax Credit for eligible energy-efficiency improvements. This is a 35 percent credit, spread over five years (or one year for projects with eligible costs of $20,000 or less), that comes off your taxes. The Energy Loan Program offers low interest loans to businesses for projects resulting in increased energy efficiency. In addition, your local utility may offer energy-efficiency rebates which often pay for sizeable portion of improvements.

How can I instantly save?
How can I instantly reduce my lighting energy use?
 
 
  • Turn off non-essential and decorative lighting, especially in unoccupied areas.
  • Replace flickering, dim and burned-out lights.
  • Clean fixtures and diffusers (at least annually).
  • Color-code or mark light switches and circuit breakers that can be turned off when not needed.
  • Use task lighting to directly illuminate work areas reducing the need for general lighting.
  • Lower the height of light fixtures if possible to increase usable light.
  • Replace burned out lights with lower wattage lights or energy-saving lights wherever possible.
  • Replacing interior incandescent lighting systems with compact fluorescent lights.
  • Replace exterior incandescent security flood lighting with high-pressure sodium fixtures.
  • Replace existing T12 lighting systems with energy-efficient T8 lighting and electronic ballasts.
  • Install more efficient security and parking lot lighting. High-pressure sodium fixtures are more efficient than metal halide, mercury vapor, fluorescent or incandescent fixtures.
  • Install time clocks or photoelectric cells to control exterior lighting, advertising sign lighting and some interior lighting.
  • Paint dark walls and ceilings with lighter colors to maximize the effect of existing light sources.
  • Maximize natural lighting by installing skylights or windows and dim or separately switch off perimeter lighting fixtures during daylight hours.
  • Install dimmer or occupancy switches where appropriate to lower energy use such as in stairwells, copy rooms, restrooms.
  • Schedule janitorial services during the day, or use a minimum number of lights when cleaning.
  • Color-code switches that should remain off when janitorial crews are cleaning.
  • Implement a group re-lamping schedule, and re-lamp at 70 percent of rated light life. Lights that run longer than 70 percent of their rated life actually cost more in terms of the ratio of energy use to light output.
  • Trim bushes and trees away from outdoor lighting to maximize illumination and prevent shadows.

Can HID sources be dimmed?
Yes. High Intensity Discharge sources can be safely dimmed down to approximately 50 percent power and 30 percent of full light output using special ballasts and control devices. But, it should be noted that as HIDs are dimmed, the color shifts. Therefore, HID dimming is generally only suitable in areas where color rendering is less important. Also, keep in mind that existing HID luminaries must have new ballasts installed to permit dimming. Doing this is often more expensive than the complete HID lighting system. Before installing dimming in HID systems, consider fluorescent replacements. New fluorescent fixtures using four to six high output T5 lamps have been designed for "high bay" applications up to mounting heights of 30 to 40 feet. These fluorescent systems are much more efficient than ordinary HID lighting, allowing maximum power to be reduced by 20 to 25 percent. The big advantage of fluorescent technology is the ability to switch lights instantly and in pairs. This permits more effective on/off and dimming control.

Removing Fluorescent lights?
Can we save energy by removing some of the fluorescent lights?
 
It depends what type of ballast is being used in the fixture. For standard 4-foot lights, you are most likely to have one of the following:
  • The most common ballast is a two-light magnetic ballast. You probably have this type of ballast if you are using F40 T12 lights. It is a series ballast, which means that if you remove one light, the remaining light will glow dimly and sputter. You should not remove a light from this type of ballast to save energy. (There are also three-light magnetic ballasts and four-light magnetic ballasts, and they are parallel-series types that will behave much like a two-light ballast, above. These are very rare, however.)
  • There are single light magnetic ballasts. Removing a light won't have any effect on any other lights, but the ballast will continue to draw some energy. Removing a light does save energy, but not nearly save as much as when you disconnect the ballast.
  • Many buildings use the modern F32 T8 lights and parallel circuit electronic ballasts. The most common electronic ballasts are three-light and four-light. In general, removing one or more lights is fine and power is reduced. The remaining lights will usually put out a little more light and the reduction in power and light is proportional.
  • There are also series and series-parallel electronic ballasts. A series electronic ballast has the same limitations as a series magnetic ballast.
 
You must also remember that many three-light lighting fixtures are wired so that there is one two-light ballast in one lighting fixture and two two-light ballasts in another, with the third light in each fixture sharing the second ballast.
 
The first test is to remove one light and see what happens. If you have series ballasts, removing one light will cause one or more other lights to turn dim and sputter. In this case, you should abandon the idea of removing lights. If the remaining light or lights continue to operate, you either have parallel circuit ballasts or single light ballasts. Removing lights is generally OK, and with each light removed, you reduce power. With electronic ballasts, the power will go down proportionately with the number of removed lights. With magnetic ballasts, the power will go down, but not as much. It is better to disconnect magnetic ballasts than to simply remove lights.
 
As with any type of electrical work, qualified electricians should be employed to disconnect ballasts and to make any other wiring changes.

T12 vs. T8?
How much energy can be saved by switching from T12 lights and magnetic ballasts to T8 lights and electronic ballasts?
 
If you replace your existing T12 lighting system with T8 lights and magnetic ballasts with electronic ballasts, you will see a reduction of lighting energy by 17 to 48 percent depending on the specific lights and ballasts. In some instances, you may want to remove some of the existing T12 lights and not replace them. You may also use one electronic ballast to serve four lights instead of one magnetic ballast for two lights previously installed. Or, you may use specular reflectors to further enhance light distribution. The overall result may bring 50 percent savings without compromising the quality of delivered light.

Renovating:Upgrade or replace?
When renovating the building, is it better to upgrade the lighting system to more efficient lights and ballasts or replace the existing fixtures altogether?
 
It all depends on your particular situation. As you are well aware, building renovation involves compliance with the current building code which may affect your decision one way or the other. Your design team (architect, engineer or contractor) should be able to advise which scheme is more beneficial to you.
Generally, if your renovations are modest and you are not changing your lighting system in any major way, most older systems can be retrofitted to use less energy. You should probably retrofit your lighting system if:
  • The fixtures are not being moved and your design team recommends retrofitting the fixtures in place.
  • You have a relatively modern lighting system that require simple cleaning and retrofitting of T8 lights and ballasts. Retrofit reflectors may permit delamping to further reduce energy use.
  • You have an open commercial or industrial lighting system that can be easily retrofitted in place.
 
You should probably replace your lighting system if:
  • It is an old style lighting system that is no longer suitable for modern office environment. Modern office space with computers generally should be updated to either parabolic troffers or suspended indirect lighting systems, and the energy savings will often pay for the cost of the new lighting system.
  • The existing lighting system is sufficiently worn, broken, or damaged to warrant a new system. The cost of disassembly, repair, washing, new reflector, wiring, ballast and lights and re-installation may well exceed the cost of removing the fixture, disposal and a new fixture purchase and installation.
 
Regardless of your decision you should check with your local utility the available rebate programs, that could reduce your capital outlay for the project.