Saving energy, maintenance with LED exit signs

Editor's note:The Energy Services Bulletin features real answers to real questions posed to our staff at the Energy Services Power Line. We hope you find it useful.

Question:

What are the potential energy savings for commercial light-emitting diode exit signs?

Answer:

Exit signs using incandescent lamps consume about 20 to 40 watts of electricity.  Energy Star-labeled exit signs – many of which are LED – consume less than 5 watts per face, potentially yielding a 75- to 88-percent savings of energy. According to the Department of Energy, if all U.S. companies switched to ENERGY STAR qualified exit signs, they would save $75 million in electricity costs.

Building owners at commercial, institutional and industrial buildings are adopting the technology. Some are simply replacing the entire sign, while others use a retrofit kit. Prices for LED exit signs have come down, further reducing life-cycle cost. Retrofit kits are available for those seeking that alternative, but the entire unit itself can range from around $80 and up, depending on the casing materials used, batteries and other options.

As LED exit signs make their way into the marketplace, it is becoming easier to find signs that meet certain characteristics or specifications. Most manufacturers and distributors offer several options, ranging from different LED colors to a variety of casings to battery-operated signs. All signs must meet UL requirements and comply with the National Electric Code, Life Safety Code and the Occupational Safety & Health Administration's standards.

Study feedback mainly positive

The Washington State University Extension Energy Program participated in a procurement research study on LED exit signs in Washington and Oregon. Most of the local governments interviewed for the project stated that maintenance costs were the primary reason for retrofitting or replacing their exit signs. The resulting energy savings were an added bonus. Some also noted that their utilities were offering a rebate to install LED exit signs, so that may have added incentive for their installation.

Some participants stated that the sign's longevity diminished if its voltage was above 130 volts. At least one manufacturer has developed an LED exit sign to work as efficiently with 130 volts. Another group that was interviewed stated that LED exit signs have a poor power factor, around 50 percent. This is not a significant concern, however, because LEDs have a low power draw.

References

• National Lighting Product Information Program, Specifier Report: "Exit Signs."
• Conway, Kathryn M. and Peter R. Boyce, "Expanding the Market for Visually Effective, Highly Efficient Exit Signs," Lighting Research Center, 1997.
• "A Graceful Exit," IAEEL Newsletter, March 1993.
• "Revolutionary New Exit Signs," Environmental Building News, May/June 1994, Vol. 3, No. 3.
• " U.S. Postal Service Specifies Energy Star in Recent Bid to Replace Exit Signs," USPS Postal News, Press Release No. 9, January 16, 1997. 
• Bibliography and references, Exit Signs and Emergency Egress.
• Bullough, John, Kun Michelle Huang and Kathryn Conway. "Optimizing the Design and Use of Light-Emitting Diodes for Visually Critical Applications in Transportation and Architecture," 11. References.

Articles and fact sheets:

• Evaluating Lighting Systems to Improve Efficiency and Effectiveness; From Energy User News
• L.E.D. Exit Signs; Energy Center of Wisconsin fact sheet.
• Lighting website of U.S. Department of Energy's Buildings Program; Resources for energy-efficient electric lighting
• Operation and Maintenance Best Practices for Energy Efficient Buildings; Western Area Power Administration fact sheet

Case studies:

• BetterBricks success stories
  Real-world examples of energy-effective design saving energy and money, creating a better work environment and increasing property value
• Case Studies: Daylighting in Schools, Office, Warehouse, and Retail
  Resources from the Lighting Research Center
• LED Traffic Signals Equal Energy Savings for the City of Portland, Oregon (pdf)
  Results of a Northwest Energy Efficiency Alliance study

Reports and documents:

• A Guide to Energy Efficient Lighting Upgrades in State Facilities
  Developed for Virginia state agencies
• Light Emitting Diode (LED) Lighting Systems (PDF)
  A report evaluating a new LED nightlight product in hotel setting
• Non-Residential Lighting Best Practices Report
  Comparative analysis of six lighting efficiency programs offered to commercial and/or industrial customers

Web resources:

• lighting.com – Searchable Web site with lighting-related articles and product directories
• Lightsearch.com – Information on companies, products and resources in the lighting field

For more resources, visit Western's Energy Solutions, or submit a question to the Power Line.