EET

LED wall wash lighting gets better

Lighting designers who use wallwash lighting got some good news recently with the release of the Dept. of Energy's latest CALiPER report – Application Summary Report 18. The report analyzed the performance of 17 LED recessed wallwasher luminaires and concluded that many of the LED recessed wallwashers perform about as well as their conventional counterparts.

The wallwashing technique is used for illuminating large surfaces in contemporary architectural schemes for public cultural buildings, museums, galleries, and so forth. This sort of illumination employs asymmetric lighting fixtures that evenly illuminate walls. Mainly used by lighting designers, wallwashing generally creates lighter spaces or makes rooms seem brighter or higher.

The new report notes that recessed wallwashers are not covered by Energy Star — the downlight category requires axial symmetry. DoE thinks this may lead to confusion about the status of the wallwasher product. For example, two of the Series 18 LED recessed wallwasher products appear to be Energy Star qualified because the logo is present on the manufacturers’ specification sheets. In both cases, the logo explicitly refered to the wallwasher product, not a standard downlight in the same family. A third product appeared to be Energy Star qualified based on the manufacturer’s webpage, although the page is for both the standard and wallwash optics. DoE says despite the presence of the Energy Star logo in relation to these products, by definition they do not meet all the Energy Star program requirements.

DoE also notes that even conventional wallwash lights have relatively poor lumen efficiency. Only 9 of the 17 Series 18 LED recessed wallwashers it tested met the DLC QPL minimum efficacy requirement of 40 lm/W, and only 7 products would meet current Energy Star efficacy requirements for downlights of 42 lm/W, if they applied. Among other LED products, this level of performance is below average, but compared to conventional wallwashers, the efficacy of many of the Series 18 products may still be an improvement.

DoE says that CALiPER testing shows that the mean efficacy of LED products has risen steadily from about 21 lm/W in 2007 to roughly 52 lm/W for products included in the 2012 reports to date. Moreover, intensity distribution and color quality have also improved markedly, as has the accuracy of manufacturer claims.

DoE also says there are far fewer low-performing products, relatively speaking, than there were a few years ago. CALiPER studies on LED replacement lamps sold in retail stores have found that many lamps purchased in 2010 were unlikely to meet consumer expectations, but those purchased in late 2011 showed substantial improvement as well as better performance at a given price. And more products were Energy Star-qualified or listed by LED Lighting Facts, equivalency claims were more accurate, and color quality improved, DoE says.

The CALiPER study is free and available here: http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/caliper_18_summary.pdf

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