The U.S. Department of Energy’s CALiPER program has released an Application Summary Report that focuses on the bare-lamp performance of 31 linear LED lamps intended as an alternative to T8 fluorescent lamps. The testing covered light output, input watts, efficacy, color, power factor and beam angle. Products listed as satisfying DesignLights Consortium criteria and those not listed were included. Lamps were tested as bare lamps, not in luminaires, with the testing covering 31 products purchased in late 2012.
DOE found:
* LED linear lamps provide similar efficacy (lumens/W) as fluorescent lamps, but typically with much lower light output. As a result, achieving suitable light levels entails relying on the directionality of the light emission to increase luminaire efficiency. However, certain application issues can result, such as changes to light uniformity, luminaire appearance and glare, which will be the subject of two follow-up reports by DOE studying lamp performance in fluorescent troffers.
* The average light output of the tested LED T8 lamps was half as much as the benchmark 32W fluorescent T8 lamp. Wattages ranged from 16 to 29W. The average efficacy was 94 lumens/W, which is marginally higher than an 80+ CRI fluorescent T8 lamp, a marked improvement over products covered in previous CALiPER testing. In terms of efficacy, the five best-performing products ranged from 106 to 143 lumens/W.
* Many of the products were rated at 4000K with a CRI of 80+, but some products were limited to a higher color temperature (cooler light appearance) and 70+ CRI.
* Measured light output, input watts or efficacy differed by more than 10 percent from performance claimed by the manufacturer in 45 percent of the tested products. Many manufacturers failed to accurately report beam angle. To assure desired performance, specifiers and buyers may consider testing products in the intended application prior to commitment.
DOE concluded: “While the efficacy of linear LED lamps is higher than for many other LED product categories, the linear fluorescent lamp is a difficult incumbent to beat, on both energy efficiency and cost. However, in terms of energy savings, the tide may be starting to turn in favor of LEDs, but it remains to be seen whether the performance changes associated with the dramatically different luminous intensity distribution (e.g., luminaire appearance, glare, illuminance distribution) will be accepted. If quality limitations restrict adoption, the energy savings potential will remain theoretical.”
When quality issues limit adoption, DOE cites several realistic and other potential remedies, including LED luminaires, omnidirectional LED lamps and LED kits or inserts.
Download the report free here.
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