Republication of Postings from the U.S. Department of Energy (DOE) Solid-State Lighting Program
by Jim Brodrick, U.S. Department of Energy
Although A lamps comprise only 10 percent of the lamps currently listed by the LED Lighting Facts program — compared with 60+ percent that are directional — they represent a key market segment because, to the typical consumer, they’re the quintessential light source and the main type of bulb purchased for home use. That’s why the shelves of retail stores are filled with such a wide variety of A lamps — and why A lamps have received so much attention from SSL manufacturers, who are seeking to capitalize on the billions of existing sockets worldwide.
Earlier this month, the U.S. Department of Energy’s (DOE) CALiPER program published a Snapshot Report on LED A lamps. In keeping with a change that was implemented in the LED Lighting Facts classification system in August of this year, the report covers products listed as either A lamps or omnidirectional replacement lamps.
Because LED packages typically emit light in only one direction, they require special optics in order to achieve the omnidirectional luminous intensity distribution of incandescent A lamps. Many of the early LED A lamps fell short in this regard and thus were inadequate for a large number of uses — a problem that was frequently compounded by weak lumen output and inflated equivalency claims.
Much has changed over the past few years, and today many LED A lamp products are omnidirectional — a development aided in part by efficacy increases that allow for smaller thermal management systems, which in turn allow for greater flexibility in optical systems. Lumen output has also increased. The multitude of commercially available LED A lamps, however, differ widely across a number of performance parameters — not just in their luminous intensity distribution, but in their energy efficiency, color quality, dimming, and compatibility with controls.
Among the Snapshot’s key findings:
* The mean efficacy of all A lamps listed by LED Lighting Facts has steadily increased, and is now at 69 lm/W.
* 95 percent of those lamps meet the current ENERGY STAR efficacy criterion, and nearly 90 percent meet the ENERGY STAR criterion set to take effect in September 2014.
* While the overall numbers for efficacy are favorable, there’s still wide variation for individual products; e.g., those with lumen output equivalent to a 60W incandescent lamp range from less than 60 lm/W to nearly 90 lm/W.
* Several LED A lamps are now available with lumen output equivalent to traditional 75W and 100W incandescent A lamps.
* Approximately 91 percent of currently listed LED A lamps have a color rendering index (CRI) in the 80s, and most of those products have a nominal correlated color temperature (CCT) of either 2700 K or 3000 K. It remains to be determined if this performance level will be acceptable to consumers, or if there will be significant demand for higher-CRI products.
It’s clear that as a category, LED A lamps haven’t reached their full maturity. Only a handful of such products can effectively replace 75W and 100W incandescent lamps, which already fall under restrictions set forth in the Energy Independence and Security Act of 2007.
To download a PDF of the full Snapshot report, please visit www.ssl.energy.gov/ledlightingfacts.html.