Guest post by Jim Brodrick, U.S. Department of Energy
t’s been a while since I’ve written about DOE’s CALiPER testing program, and the Round 11 Summary Report was published this week. As always, the results are worth noting. For those of you who don’t know, CALiPER tests a wide range of solid-state lighting products that are available on the market, and for benchmark purposes compares them with similar products that use traditional light sources. The results of each round of testing are highlighted in a Summary Report, with detailed reports going into greater depth.
CALiPER Round 11 was conducted from March to September of this year and looked at 31 LED lighting products in five applications: arm-mounted roadway luminaires, post-top roadway luminaires, linear replacement lamps, high-bay luminaires, and small replacement lamps. Overall, there were some encouraging findings. For example, we saw a continuation of the steady increase in average overall efficacy over previous rounds. And although many products continue to carry misleading equivalency claims and inaccurate performance metrics, performance claims for a number of products were found to be accurate – especially for those products carrying the Lighting Facts® label.
Regarding LED linear replacement lamps, there’s good news and bad news from Round 11. The good news is that they’re getting better, especially in terms of efficacy – but the bad news is that they still have some major performance issues in the areas of light distribution, color quality, and reliability. Still, using a troffer equipped with two SSL lamps to replace a single-lamp fluorescent troffer in situations where lower light levels are needed, or where other SSL characteristics provide an advantage, may now be viable in some cases – even though at this point in time LED linear replacement lamps will probably not be the most cost-effective or reliable option.
There’s been a lot of interest lately in outdoor applications for SSL, which makes the Round 11 roadway luminaire findings especially timely. Those findings were a mixed bag. Both the arm-mounted and the post-top luminaires showed a wide range in performance, although there was significant improvement on average over earlier rounds. Half of the SSL outdoor luminaires achieved light output and efficacy levels that matched or exceeded those of their benchmark counterparts, but most of those tested exhibited substantial variations in color characteristics (either CCT, Duv, or both) as compared to their rated CCT.
Five out of the six arm-mounted roadway LED luminaires tested met or came close (within 10%) to meeting manufacturer ratings for expected light output and efficacy. But both types of outdoor luminaires showed a broad range of distribution characteristics, which would require close analysis to determine their adequacy for a given application. While some of the LED products claim equivalency to 100W HPS, that equivalency may only be valid in a limited number of installation scenarios. In other words, depending on the particulars of a site, these LED products may or may not be suitable for that site.
So what’s the take-home message here about outdoor lighting, based on CALiPER Round 11? That evaluating it is not a simple matter. There are a lot of subtleties that come into play and have to be taken into consideration, which means that potential users need to look closely at the specific application, to see whether a product is suitable or not.
There’s a huge range in the performance of these LED products. Many wouldn’t make suitable one-for-one replacements when used with existing street-lighting systems, but might make economic sense with new installations. Why? Whether seeking to replace existing luminaires with LED or some other technology, the replacement product will always be faced with the challenge of competing in an application that was likely optimized around the existing product. Pole spacing may be somewhat flexible in new installations, thereby offering opportunities to optimize the installation for LEDs.
So when evaluating LED lighting products, there’s really no substitute for looking carefully at the requirements of each application and looking at photometric data obtained from standardized testing for each product being considered. And that holds true not just for roadway lighting, but pretty much across the board. Doing that can expand the options, while minimizing the likelihood of making a decision that will later be regretted.
