An interesting piece from the current issue of LED’s Magazine highlighted developments and challenges in LED lighting. Jim Brodrick, the US Department of Energy’s LED lighting guru (http://www1.eere. was the headliner at the LEDs 2011 conference on October 25 in San Diego. DOE is doing very aggressive work in getting solid-state lighting up to speed because of the technology’s tremendous potential for energy savings. (A recent DOE report estimates that LED lighting could save enough electricity to power 19 million homes.)
Brodrick pointed out the challenges in getting from here to there and that to get the optimal combination of light output and energy savings, products have to be designed from scratch. Unlike fluorescent lights, which emit light from all sides of a tube, LEDs only go in one direction. That means that a fixture designed to reflect light from its innards isn’t really going to be effective if you just stick an LED in it. Brodrick stated that the best performance so far has been coming from LED fixtures designed to replace conventional recessed downlights, outdoor area lights, 2 ft x2 ft lay-in troffers and refrigerated-case lights. He was less impressed with the progress in applying LEDs to directly replace standard incandescents (A-lamps), straight-tube fluorescents and fluorescent cove lighting. With regards to incandescent replacement lamps Brodrick stated that although the lamps are improving, “generally they don’t match the output, color quality, and light distribution” of incandescent sources. The full article can be found at http://www.ledsmagazine.com/news/8/10/30?cmpid=EnlLEDsOctober262011.
I share his skepticism about LED products that are designed to directly replace fluorescent tubes. For one thing, there are safety and maintenance concerns. Some of these products are designed to run on line voltage, which means the ballast must be removed and the lampholders (tombstones) connected to the building voltage. Pity the person who unknowingly installs a standard fluorescent tube in these figures. If you install these, put the insurance agent and attorney on speed dial. LED tubes that use the (very low) ballast voltage are safer, but what happens when the ballast fails? Many T8 lamp and ballast installations are 10 to 15 years old, or older, and ballasts are reaching the ends of their natural lives. The bottom line, though, is that there’s a better way to use the light-producing qualities of an LED than to stick it deep inside a 2’x4’ fixture. New light sources require new forms. Incandescent lights were originally designed to fit inside or replicate gas lighting (which was similar to candles and kerosene lighting). I’m sure it took years for people to accept the recessed incandescent (try doing that with a flame!). When fluorescent lights came out in the 1930’s, they took on a new shape to match the new light source. Now that LEDs are reaching maturity (adolescence?), they need shapes and forms that match their strengths. I don’t know what those shapes are, but the end goal remains to provide good lighting.
