The Next Wave in Lighting Energy Savings

November 11, 2003

What do most people think of when lighting is mentioned to those involved in energy efficiency? For many energy professionals, lighting energy efficiency opportunities are represented by the T8 lamp and electronic ballast retrofit. While the energy savings opportunities of the T8/electronic retrofit "movement" are undeniable, that particular solution is truly the tip of the iceberg with respect to the benefits of energy efficient lighting.

Lighting technology offers tremendous opportunity. Energy savings often ranges from 25 to 40 percent, while the most aggressive solutions can deliver as much as 75 percent savings. There is also an opportunity to deliver tangible non-energy benefits to the occupants of a building, if thoughtful consideration is given to design solutions that support comfort, preference, and the task work of the federal workforce. FEMP technical assistance in the area of lighting is designed to support energy professionals in making the most of lighting energy opportunities.

Lighting Standards Have Changed

A few years ago, the primary metric for lighting was the horizontal footcandle. This is a technical measurement for the amount of light delivered to the horizontal task (such as a desktop or workbench). The Illuminating Engineering Society of North America (IESNA) is the standards-writing organization in the field of lighting, and the IESNA Lighting Handbook provided a long list of footcandle requirements for the many and varied types of applications. In 2000, Lighting Handbook (9th edition) the lighting standards changed in a profound and fundamental way. No longer are footcandles the only metric. In fact, footcandles are often secondary or tertiary in importance. Chapter 10 of the Lighting Handbook now provides a matrix of design requirements for each type of application that must be addressed in order to meet the minimum standard of care. This is a fundamental shift in practice and represents a challenge and opportunity for federal energy managers.

Photo of overhead lighting.

Strategy to reduce overhead glare; South Admin Area-National Laboratory Center; Bureau of Alcohol, Tobacco, Firearms and Explosives; Ammendale, MD.

For example, an appropriate design for offices should now include lighting the walls (vertical illuminance) and reducing glare. There are many kinds of glare, and one of the most common offenders is often overlooked. Concerns about reflected glare in the computer monitor screen is less of a concern than it used to be due to the improvements in screen technology. One of the most frequent offenders in current practice is overhead glare. This requires a fundamental shift in strategy for lighting energy savings, as explained below.

Many retrofit solutions are geared toward focusing the light downward with the use of specular reflectors. This was considered an improvement because there was an increase in horizontal footcandles for less energy. However, in the context of the current standards this creates a problem in several ways. First, it can create an experience of discomfort for the occupant due to the increased intensity of the light overhead. Second, it reduces the amount of light delivered between the fixtures (uniformity). Third, the downward focus of the light reduces the brightness on the walls.

So what are the new solutions that meet the IESNA standards and provide visual comfort and satisfaction for occupants? FEMP technical assistance can help. Consider the following partial list of information and tools prepared to support agencies, energy services companies, and utilities. All of these tools can be found through the FEMP Web site.

  • Energy Effective Lighting Checklist. A front-and-back checklist to help achieve maximum efficiency while still meeting the current standards.

  • Benefits of Energy Effective Lighting. This piece describes the non-energy benefits of effective lighting in terms that are understandable by the layperson.

  • Economics of Energy Effective Lighting for Offices. This 4-pager provides comparisons of several design solutions with both simple payback and federal savings-to-investment ratios.

  • FEMP Lights Basic Training. This Web-based course is recommended for anyone who is managing or delivering a federal lighting project.

  • Web-based Occupant Satisfaction Tool. Use this tool to measure the satisfaction of building occupants-identify problems or capture project-related satisfaction improvements.

There are some lighting challenges that require assistance geared specifically toward a particular agency or project. For example, many agencies and service providers have not yet updated their boilerplate specifications to reflect the new lighting standards. Certain lighting projects require specialized attention and may merit design assistance. FEMP can provide technical assistance in these areas.

Photo of lighting in a laboratory.

Alcohol LaboratoryNational Laboratory Center; Bureau of Alcohol, Tobacco, Firearms and Explosives; Ammendale, MD.

FEMP Lighting Partnerships

In addition to the tools and services mentioned above, there are some other resources and services that will help to ensure a successful lighting project. FEMP has been a partner in lighting industry efforts that result in resources and services.

Advanced Lighting Guidelines. FEMP has supported the development and maintenance of this landmark technical resource. The 2003 revision has recently been completed, and limited copies of the CD are available through the EREC hotline courtesy of FEMP. The Advanced Lighting Guidelines can be viewed for free on the Web at www.newbuildings.org.

National Council on Qualifications for the Lighting Professions (NCQLP). FEMP is a member of the NCQLP. People with "LC" (Lighting Certified) credential have demonstrated an ability to apply fundamental lighting principles and techniques in the NCQLP Lighting Certification exam. Having LC professionals on federal projects will increase the likelihood of successful lighting solutions. Projects that are especially challenging or unique will benefit from professionals that have lighting design expertise and a portfolio of successful project work.

Lighting Technology Opportunities

Lighting technology is evolving at a rapid pace, and there are a number of opportunities that are available but still not commonly installed in federal buildings.

High performance T8 lamps and electronic ballasts. There have been significant improvements made to the T8 lamp, and each of the three major lamp manufacturers have high performance lamps with increased lumen output, improved lumen maintenance, longer life, and improved color rendering. There have also been numerous improvements in electronic ballast technology. Paired with the right ballast, this high performance system can save 10 to 20 percent as compared to a standard T8/electronic ballast system. In some cases, this may even merit a retrofit of a system that has already been retrofitted from T12 lamps to standard T8.

Task-ambient lighting with T5 lamps and semi-indirect pendant fixtures. Indirect lighting provides a tangible improvement in the lighted environment, but historically has been out of reach for federal facilities for cost reasons. In recent years, costs have dropped dramatically and semi-indirect steel fixtures are available at the same installed cost as parabolic 2x4 fixtures. The new T5 lamps are more efficient with respect to lumen output and photometric availability, and so the fixtures can often be placed 15 feet on center, which is a significant reduction in connected load. It is acceptable to provide a reduced horizontal illuminance of 35 to 40 footcandles, but only if an articulated (moveable arm) desktop task light with compact fluorescent lamps is made available.

Lighting controls. Lighting controls are a tremendous energy savings opportunity. It is critical to find the right solution for your occupants. Maintenance and commissioning are a key element of success with lighting controls. Refer to the Advanced Lighting Guidelines for more information about lighting controls.

To summarize, it's clear that coming up-to-speed with respect to the newest lighting standards and technologies is an opportunity that we can't afford to miss.

For more information, please contact Carol Jones of PNNL at 781-895-1013 or carol.jones@pnl.gov.