"There's a gap between data and reality," he said. "Bad data causes confusion in the marketplace, and can result in a loss of credibility for LED technology."
As the DOE commercial product testing program has demonstrated (see LEDs Magazine February 2007, p8), many commercial LED fixtures fall far short of their stated values of efficacy and lumen output. One very obvious error is that a fixture datasheet may quote the efficacy value for an individual LED. Within the fixture itself, depending on the quality of its design, optical and electrical losses can easily reduce the efficacy by 30%. The new Energy Star ratings for LED fixtures are all based on luminaire (rather than LED or LED system) efficacy.
Hunter criticized companies (both LED and fixture makers) for producing figures that are driven by marketing, and also criticised the press for being willing participants/victims of the hype. "A result [for LED performance] might be reported in lumens/watt, but the price, package type, chip size or measurement technique is not disclosed," he said. "Such results set up false expectations, and have made some traditional light fixture manufacturers sceptical of stated performance. As a result, the industry suffers."
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This article was published in the April 2007 issue of LEDs Magazine.
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