New publication examines and explains “full-spectrum” lighting

* What is it? What does it do for us? Is it worth the price? *

Light sources promoted as full spectrum can cost ten times more than nearly identical products that do not bear the full-spectrum claim. Lighting Answers: Full Spectrum Light Sources addresses questions about these products: What are they? How valid are the claimed benefits? Are they worth the extra cost?

Various manufacturers have different ideas about what a full-spectrum light source is and why it yields the claimed benefits. Some say that invisible-to-the-eye UV (ultraviolet) radiation is a necessary ingredient in full-spectrum light. Recently however, several lighting products have emerged that reduce radiation in a small part of the visible spectrum in an effort to improve visibility—and these products are also called full-spectrum. This Lighting Answers report proposes a convenient definition for full-spectrum light sources that can quantify the extent to which a given light source deviates from a full-spectrum light source.

LRC Director Mark Rea, Ph.D., who led the team of researchers examining full-spectrum lighting, says most full-spectrum light sources are marketed at a premium price over other light sources, but generally produce fewer lumens per watt. If manufacturers’ claims are valid, says Dr. Rea, the benefits claimed for full-spectrum light sources would seem to be worth the additional expense and the loss in efficacy. “The problem is,” Rea explains, “with each manufacturer making up its own definition of full-spectrum lighting, consumers have no way to know exactly what they are getting, let alone what benefits to actually expect.”

The report also explores consumer perceptions about full-spectrum light sources. Consumers searching for healthy lighting solutions are often told by manufacturers and retailers that full-spectrum lighting products simulate natural sunlight and improve color perception, visual clarity, mood, productivity, mental awareness, student performance, retail sales, and plant growth. They also, according to some claims, enhance the results of light therapy in treating seasonal affective disorder (SAD) and sleep disorders, promote vitamin D synthesis in the body, and even reduce incidence of dental decay.

“Full-spectrum lighting has been a topic of conversation in the technical community for many years,” said Dr. Rea, “but there have been very few discussions about the strengths and weaknesses of light sources claiming to be full spectrum.” Because there has never been a formal definition of full-spectrum lighting, Rea says it has been difficult to quantitatively compare light source characteristics. “This publication takes a significant step away from non-technical marketing and toward educating the specification community about full-spectrum lighting and its properties.”

About NLPIP and Lighting Answers

The Lighting Answers series of publications answers specific questions about lighting products relevant to lighting decision makers and end users. NLPIP (the National Lighting Product Information Program) publishes reports designed to aid facility managers, utilities, lighting designers, engineers and electrical contractors in choosing the right products for the right applications. Currently, all NLPIP reports in Adobe Acrobat PDF format are available free to the public at www.lrc.rpi.edu/programs/NLPIP/publications.asp.

About Rensselaer

Rensselaer Polytechnic Institute, founded in 1824, is the nation's oldest technological university. The school offers degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve students and working professionals around the world. Rensselaer faculty members are known for pre-eminence in research conducted in a wide range of research centers characterized by strong industry partnerships. The Institute is known for its success transferring technology from the lab to the marketplace, allowing new discoveries and inventions to benefit human life, protect the environment, and strengthen economic development.

The Lighting Research Center (LRC), part of Rensselaer Polytechnic Institute, is the world’s leading university-based research and education institution dedicated to lighting. Located at 21 Union Street in Troy, New York, the LRC employs an expert staff of nearly forty researchers, educators, designers, and scientists committed to “advancing the effective use of light and creating a legacy of positive change for society and the environment.” Visit LRC’s Web site at www.lrc.rpi.edu.