Light-emitting Diode (LED) replacement lamps, including omnidirectional, directional and decorative lamps, are now proliferating the market.
Unfortunately, many of these products have been of poor quality, according to CALiPER independent product testing conducted by the Department of Energy (DOE). Tested lamps have demonstrated wide variations in performance, the performance is routinely grossly overstated, few products are competitive against the sources they are intended to replace, and most products are fairly new, with little time in the field. For example, some products were found to last less than 500 hours despite claims of 50,000 hours.
On the other hand, performance is increasing, and viable replacement lamps are entering the market, particularly those intended to replace lower wattage lamps, such as decorative ones. How can buyers separate the wheat from the chaff?
On Aug. 31, 2010, the final Energy Star criteria for integral LED replacement lamps became effective. Energy Star is a voluntary labeling program designed to help consumers identify energy-efficient, cost-effective products. To earn the label, a manufacturer’s product must meet strict efficiency and performance criteria established by the DOE.
In the case of LED replacement lamps, the criteria require the product to be at least as efficient as comparable compact fluorescent lamps while providing light output, color and distribution equivalent to incandescent or halogen lamps.
The criteria cover lamps in nonstandard forms (which may not claim equivalency with any standard lamps) as well as in forms intended to replace existing standard electric lamps (which may claim equivalency). Criteria covering the latter include omnidirectional (light emitted in all directions), directional (80 percent of light output falling within a 120-degree cone) and decorative lamps (globes, candles, etc.). Let’s look at omnidirectional and directional lamps.
Omnidirectional lamps—including A, BT, P, PS, S and T—must operate at a minimum efficacy of 50 lumens per watt (W) for <10W LED lamps or 55 lumens/W for 10W. The lamp must produce light output based on the wattage intended for replacement, expressed on a scale starting at 200 lumens (being able to claim replacement for a 25W incandescent) and running up to 2,600 lumens (150W replacement). Not surprisingly, the lamp is expected to produce a uniform 360-degree distribution.
Directional lamps—including BR, ER, K, MR16, PAR16, PAR20, PAR30, PAR30LN and PAR38—must operate at a minimum efficacy of 40 lumens per watt for 2.5-inch-diameter and 45 lumens per watt for >2.5 inch-diameter lamps. The lamp must produce a minimum light output of 10 times the wattage of the lamp intended for replacement. Determining the equivalent conventional directional lamp is based on entering wattage and beam angle into a center beam candlepower calculator (Note: for several reasons, it is not a perfect equivalent; performance may still vary).
For both omnidirectional and directional lamps, the lamp’s color tone must be 2,700K, 3,000K, 3,500K or 4,000K; exhibit a certain level of color maintenance; and have a minimum color rendering index (CRI) rating of 80, with R9>0. If the lamp is >5W, it must have a power factor 0.7. Finally, it must have a rated service life of at least 25,000 hours and have basic information published in a standard Lighting Facts label on the product packaging.
What is R9, and why is it important? CRI is based on an average of the R1 through R8 color palette. R9 through R14 are saturated colors; R9 is the saturated red. Halogen sets the bar with an R9 of 100. A high R9 is important for rendering red well in display lighting for food, flower, clothing and similar applications. Many new ceramic metal halide products commonly used in retail display lighting, for example, claim high R9 values.
What is rated life based on? LED replacement lamps are different than most light sources in that rated life is based on useful life reflecting lumen depreciation, not failures reflecting mortality. Energy Star recognizes an L70 rating as the industry standard. An L70 rating means, at the product's rated service life, it will be producting 70 percent of its full light output.
What about dimming? Dimming reduces LED internal temperatures, which can increase efficacy and extend product life. However, not all LED replacement lamps are dimmable, and not all dimmable products are compatible with all existing dimmers. The DOE is currently working with NEMA on a dimming standard. Until then, Energy Star only requires that the manufacturer clearly state whether the product is dimmable on the product packaging and then publish information on a webpage about dimmer compatibility (several manufacturers, including Leviton Manufacturing Co. and Lutron Electronics Co., have recently introduced dimmers specifically made for LEDs).
What about LED linear T8 replacements? DOE has bluntly stated that these products are not ready for primetime, based on product testing in which LED lamps were found to produce only a third of the light output of the lamps they are intended to replace.
Energy Star criteria helps contractors feel confident that a given LED replacement will perform—in terms of light output and distribution—as well as, or better than, the to-be-replaced lamp.
DILOUIE, a lighting industry journalist, analyst and marketing consultant, is principal of ZING Communications. He can be reached at www.zinginc.com.