Introduction

Lighting is probably the first place in a facility to look for when attempting energy savings as an easy and inexpensive changes can give a quick return. Of the few steps to be assessed are: current lighting conditions: measure current conditions against calculated upgrades; understand current lighting conditions and needs that will aid in determining applicable opportunities and recommendations.

Assess Existing Conditions

To conduct a lighting audit initially basic lighting information is needed, such as the number of lights, their location, and their time in use to help one understand the current energy use attributed to lighting in the facility. This information will help auditor understand how much you are currently spending and the potential savings available from lighting efficiencies.

Opportunities for Increasing Lighting Energy

Determine if the following opportunities exist for a given location. Each checkbox represents an opportunity for energy savings followed by suggestions on how to best take advantage of the opportunity.

Turn off lights in unoccupied areas

1. Post reminder stickers to turn off lights when leaving the area. Install time switches or occupancy sensors in areas of brief occupancy and remote areas (warehouses, storage areas, etc.).
2. Rewire switches so that one switch does not control all fixtures for multiple work areas.
3. Ensure wall-switch timers function properly.
4. Determine if existing lighting levels are higher than recommended levels.

1. Reduce lighting levels where appropriate.
2. Reduce lighting hours.
3. Employ uniform or task delamping to reduce power and lighting.

Review outside lighting needs

1. Without compromising on safety and security eliminate outdoor lighting where possible.
2. Manually turn off lights.
3. Replace burned out lamps with lower wattage lamps.
4. Replace exterior incandescent lights with more efficient lights, such as high pressure sodium (HPS) or metal halide (MH).
5. Install photoelectric or motion sensors where light needs are intermittent.
6. Ensure existing sensors function properly.

1. Remove fluorescent lamps controlled by magnetic ballasts in pairs since they are operated and wired in pairs (two fluorescent lamps from a four-lamp fixture). With electronic ballasts, each lamp is controlled individually. Some facilities have seen an energy savings of more than 30 percent or more from this action.
2. Remove unnecessary tubes and replace them with “dummy” tubes that draw little current and provide the effect of uniform lighting.
3. Disconnect ballasts, as the ballast will continue to use energy when the fixture is switched on.

Install more efficient lighting

• Replace incandescent lamps in offices, work rooms, hallways, etc. with compact fluorescent lamps (CFLs).
• Use single incandescent lamp of high wattage instead of two or more smaller lamps of combined wattage. Efficiency of incandescent lamps increases as lamp wattage increases.
• Replace non-decorative incandescent lamps with fluorescent or high intensity discharge lamps.
• Replace standard fluorescent lamps and ballasts with T8 and matching electronic ballasts (switching from fluorescent to high-efficiency fluorescent can save 10 to 30 percent in energy costs).
• Replace fluorescent lamps with more efficient HPS lamps.
• Replace mercury vapor lights with higher efficiency MH or HPS lamps.
• Employ more effective lighting settings.
• Lower fixtures or use a lamp extender to increase illumination on a given area.
• Install reflectors or lenses to spread out and focus light (specular reflectors can improve efficiency by up to 17 percent in fluorescent lights).
• Use light-colored paint on walls.
• Ensure the layout of room is conducive to light and that light obstructions do not exist.
  

Follow a regular maintenance schedule

• Establish a regular inspection and cleaning schedule for lamps and fixtures.
• Establish a group relamping schedule to replace lamps as they burn out, usually done at 70 percent of rated lamp life. Group relamping will cut down on both energy and labour costs. Energy is still consumed while lumen output of fluorescent lamps decreases with age.
• Replace yellow or hazy lens shading with new acrylic lenses that do not discolor.
• Clean room surfaces such as tables, walls, etc. to remove dirt, increasing reflectivity.
• Use day lighting effectively.
• Locate workstations with high illumination needs adjacent to windows.
• Turn off lights when daylight is sufficient.
• Install light sensors/dimming equipment that automatically compensate for natural light variance.
• Clean windows and skylights.
• Reschedule housekeeping duties to operate during the day so additional after-hours lighting is not needed.

Upgrade exit signs with the help of an expert.

• Retrofit by replacing incandescent lamps with CFLs.
• Retrofit by replacing incandescent lamps with light-emitting diode (LED) lamps, which use one-tenth the electricity of incandescent lamps and have a life span of more than 100,000 hours.
• Replace old exit signs with new LED signs.
• Remove unnecessary lighting in beverage machines.
• Train staff, especially housekeeping staff, on lighting policies/efficiency.
• Post lighting schedules that display necessary hours of use for lights so that staff members know when turning off lights is appropriate.

Calculate the Savings

For each change use the following formulas to calculate annual savings:

(____watts x ____ hours per day x ____ days per year)/ 1,000 wh/kWh = ____ kilowatt hours (kWh)

____ kWh x cost per kWh per year = ____ total annual kWh charges saved by this change.

Additional tools are available to calculate potential energy savings, environmental improvements and payback for upgrade conversions.

Pollution Prevention Savings

Upgrading a typical four-lamp, 2-foot by 4-foot fixture from a magnetic ballast and 34 watt T-12 lamps to a partial output electronic ballast and 32 watt T-8 saves 43 watts. Based upon an average 3,000 annual operating hours, upgrading 35 fixtures would reduce carbon dioxide emissions from the power plant equivalent to that of removing a car from the road. The payback on this investment would be 2.74 years at a rate of 8 cents/kWh.