Other points stressed by these presenters were that LEDs are only appropriate for a limited number of applications, such as tasklighting, cove lighting, façade lighting, and exterior and area lighting. When it comes to general lighting, such as for laboratories, classrooms, and lecture halls, LEDs are not yet competitive.
LEDs are also having a significant impact on the preparation and writing of lighting specifications. Typically, a three-name specification (the named manufacturer with alternates) is required on public university projects. But when it comes to proprietary LED systems, this is virtually impossible. Competing LED products are not comparable or easily interchangeable, and this is why a professional integrator is absolutely necessary for comprehensive LED lighting and controls installations—there needs to be someone to coordinate the system and take responsibility for the appearance, life, and long-term function of the LED lighting and controls. Electricians may not be familiar with DC circuits, series wiring, loading issues, and controls incompatibility, and they need dedicated training for working with LED products.
Finally, LEDs present a whole new set of issues when it comes to outdoor lighting. Lighting design is all about balancing quantity and quality. Outdoor luminaires that have a wider beam spread may look energy efficient because they can be spaced farther apart, but these fixtures create more glare, and glare wastes energy. Dark Sky–sensitive design may need to be balanced with a little uplight on a tree-lined street to provide a sense of safety. Cutoff, light pollution, light trespass, directed optics, and visual interest are all important considerations, as are common outdoor LED failure issues with water, temperature, and connections.
LIGHTING MANUFACTURERS’ PERSPECTIVES Terry Clark of Finelite and Ann Reo of io Lighting, a Cooper Lighting brand, discussed LEDs from a manufacturer’s point of view. Each has struggled with components and compatibility issues in cases of research, development, and production. To counter some of the “hype” surrounding LEDs, which has (to a certain extent) been disruptive to this growing industry, they stressed several points.
First, venture capital funding of the semiconductor industry has changed the dynamics of the lighting industry. There is pressure on emerging lighting companies to deliver a return on investment within two years, rather than waiting until the product is ready for market. Consequently, some manufacturers who were “early adopters” are getting burned, and false performance claims coupled with faulty products by some has resulted in a cloud of doubt over LED technology.
Second, in order for LED luminaires to be successful, all components have to work flawlessly together. At the moment, they don’t. This means that luminaire manufacturers spend enormous sums fixing problems in the field. One step toward addressing these issues of compatibility and reliability is the Lighting Facts labeling program, and so are the standards that are being developed specifically for LEDs. LM-79-08 (“IES Approved Method: Electrical and Photometric Measurements of Solid-State Lighting Products”) and LM-80-08 (“Approved Method: Measuring Lumen Maintenance of LED Light Sources”) have been released to help, and they are increasingly being adopted as a starting point for assessing LEDs. TM-21 (“Lumen Depreciation Lifetime Estimation Method for LED Light Sources”) is still in development. At present, the industry has no consensus on how to predict LED life. Knowing when an LED product has reached its end-of-life is not easy. When a filament lamp reaches its end-of-life, it stops working. An LED’s light output diminishes over time, and no one can clearly say at what point the product’s output is no longer sufficient.
HOW TO PROCEED? Everyone—the lighting industry, designers, clients, facilities staff, and end-users —wants LEDs because of their long life, their small size, and their potential energy savings. The SSL in Higher Education Workshop was an informative forum that allowed facility managers, lighting designers, and lighting manufacturers to further the development and improvement of LED products and their applications. Ultimately, the discussion pointed toward the following recommendations: If LED technology is to be successful, more research and development is needed in order to fully study drivers and other components. Additionally, LED luminaires need to be marketed, specified, and installed as systems, not components, and the manufacturer’s warranty should cover all the components. In the case of higher-education clients, extended warranties may be appropriate. Going forward, there might also be the need for third-party testing to ensure product compatibility across manufacturer offerings. Finally, LED products are only out in the market just a short time before the next-generation LED technology is available, making it difficult to ensure that the absolute latest luminaire offerings are what will be specified and installed on a project. It would be extremely beneficial to establish a recycling system whereby manufacturers would accept older SSL products, properly recycle them and provide some kind of a rebate toward the replacement of the fixture with the most current LED technology.
Solid-state lighting has changed the rules of the lighting game. There’s still a long way to go, but workshops such as this one are a start in furthering the discussion. To read the report about the workshop, visit the DOE at ssl.energy.gov/higher_ed_workshop2010_materials.html.
Naomi J. Miller is a senior lighting engineer with the Pacific Northwest National Laboratory, and has 30 years of experience in lighting design and application dedicated to improving energy efficiency and lighting quality in the built environment.