DOE unveils results of Round 2 of testing program

The performance of commercially available solid-state lighting products ranged from "excellent to dismal" according to results of Round 2 of product testing from the DOE's Commercial Product Testing Program (CPTP).

As part of the DOE's Solid State Lighting (SSL) program, the CPTP Round 2 tests were carried out from March to May 2007 on a wide range of products, including replacement lamps, downlights and desk-task lamps. The results, along with those published for Round 1, are available at www.netl.doe.gov/ssl/comm_testing.htm.

Table 1 The test procedure LM-79 was used, which involves testing the luminaire as a whole system, ensuring that all aspects of control electronics, heat sinks and other factors are included. Replacement lamps were mounted for testing using standard lampholders, and appropriate fixture losses should be applied to determine the performance of such a lamp inside a luminaire.

The Round 2 results showed widely divergent performance. Some downlights and directional replacement lamps produce light output comparable to similar incandescent and CFL downlights, and have higher efficacy (see Table 1). The DOE says that upcoming testing on more recent SSL downlights is expected to show more that are close to or surpassing CFL products in output and efficacy.

However, replacement A-lamps performed very poorly, producing less than 20 lumens. This is less than 5% of the light from a typical A17 or A19 incandescent lamp and makes the LED version very unsuitable as a "replacement" in most situations. Moreover, the manufacturer's literature for one such A-lamp suggested that electricity consumption was 80-90% lower. In truth, this was purely as a result of the very low light output.

Disparity between test results and manufacturers datasheets was highlighted in Round 1 of the testing program, and the situation has not improved. The Round 2 results showed that only two of the tested products had test results similar to the manufacturer's literature. All the other products overstated their performance claims by 25-35% for efficacy and 30-95% for light output.

Outdoor lamps and refrigerated display case lamps performed well in terms of efficacy and light output. Other factors may be as important as efficacy for these applications, including cold temperature performance, longer lifetimes, controllability, dimmability, and insensitivity to frequent on/off cycling.

Table 2 Task-desk lamps generally did not meet performance expectations. A direct comparison was made between an LED product (test ID 07-22) and an equivalent model with a halogen light source (07-10). The LED version had higher efficacy but produced only about 50% of the light output. The halogen version had warmer CRI and much better color rendering (CRI) than either LED-based product.

However, the biggest discrepancy occurred when off-state power consumption was considered. As shown in Table 2, the LED product (07-22) consumes a huge 2.5 W of power when nominally switched off, as a result of inefficient electrical design. As a result, the average efficacy for the LED products is much lower (for more on this subject, see Make sure the LED luminaire you choose is a "Sleeping Beauty").

Round 2 also looked at power factor. In the draft Energy Star requirements for SSL luminaires, the minimum power factor value is 0.7. All the Round 2 luminaires that are integrated fixtures have power factors above 0.7, while those that are replacement lamps are below 0.7 (and the A-lamps were below 0.4).