Ask the Energy Optimization Experts: Lighting Efficiency
Question: How can I improve the lighting efficiency of my facility’s system?
Answer from the Energy Optimization Experts: Lighting efficiency system issues, which include problems with outdated fixtures, uncontrolled fixtures and cleanliness can take several forms. An energy audit will typically identify energy inefficiencies in one or several of the following areas:
- Incandescent lamps are used in offices, workrooms, hallways and gymnasiums
- Lamps and fixtures are not clean
- Lamps are replaced individually as they burn out
- Ceilings and other room surfaces have reduced reflectivity due to dirt
- Daylight is not used effectively
- Decorative lighting is excessive and/or not controlled optimally
- In fixtures where fluorescent lamps have been removed, the ballasts have not been disconnected
- When burned out fluorescent lamps and/or ballasts have been replaced, more efficient lights have not been installed
- Lighting is on in unoccupied areas
- Security/outdoor lighting is not automatically controlled and/or lighting levels are excessive
- Deep baffled downlighting fixtures have conventional “R” reflector lamps installed
- Two lamps have not been removed from four lamp fixtures
The suggested operations and maintenance improvements and facility improvement measures will vary based on your facility’s unique mix of inefficiencies, but what follows are some general guidelines.
Suggested Lighting Efficiency Operations and Maintenance Improvements:
- Where possible, use a single incandescent lamp of high wattage rather than two or more smaller lamps of combined wattage.
- Discontinue using extended service lamps except in special cases such as recessed directional lights where short lamp life is a problem.
- Discontinue using multi-level lamps. The efficiency of a single wattage lamp is higher per watt than a multi-level lamp.
- Establish a regular inspection and cleaning schedule for lamps and fixtures. Dust buildup reduces effectiveness.
- Replace lens shielding that has turned yellow or hazy with new acrylic lenses which do not discolor.
- Replace outdated or damaged fixtures with modern types that are easy to clean.
- Establish a group relamping schedule.
- Clean ceilings, windows and skylights.
- When repainting or recovering, use coatings or coverings with good reflectance.
- Locate work stations requiring high illumination adjacent to windows.
- Switch off lights when daylight is sufficient.
- Replace burned out lamps with lower wattage lamps.
- Establish a schedule for manual control or control operation with existing photoelectric or time clock controls if practical.
- Disconnect ballasts, which still use a significant amount of energy even though the lamps have been removed.
- When relamping, replace fluorescent tubes with more efficient and lower wattage types. Wherever possible, replace burned out ballasts with more efficient, lower wattage, energy conserving ballasts.
- Consider not replacing burned out lamps and disconnecting ballasts in areas where delamping is possible.
- Post instructions to turn off lights when leaving the area.
- Identify areas being controlled by ganged switches.
- Assure wall switch timers function properly.
- Establish manual operation schedule considering change in daylight with season.
- Control lighting with existing photoelectric or time-clock controls if practical.
- Eliminate outdoor lighting where practical.
- Replace burned out “R” lamps with elliptical reflector “ER” lamps which yield approximately the same average light level for half the energy costs.
- Remove two lamps from four lamp fixtures and disconnect ballasts.
Suggested Lighting Efficiency Facility Improvement Measures:
- Replace non-decorative incandescent lamps with more energy conserving types such as fluorescents in general purpose areas and HIDs in large group areas.
- Install light sensors and dimming equipment which automatically compensate for varying natural lighting conditions.
- Replace unnecessary tubes with “dummy” types which draw little current and yet provide uniform lighting effect.
- Install more efficienty fluorescent tubes and ballasts in all existing fixtures (Note: Verify that new lamps will work with existing ballasts).
- Lowering fixtures will increase illumination levels on the task area, and may permit a reduction in the number of fixtures or the wattage of lamps.
- Reduce high bay lighting by installing task lights at work stations and lights at work stations.
- Rewire switches so that one switch does not control all fixtures in multiple work spaces.
- Provide timer switches in remote or seldom used areas where there will be brief occupancy periods.
- Replace exterior incandescent lamps with more efficient types.