Energy Star Labels for LED Lighting

Energy Star Criteria for Specific LED Lighting Applications

There will soon be an Energy Star label for light-emitting diode (LED) light fixtures. The U.S. Department of Energy (DOE) has tasked the Pacific Northwest National Laboratory (PNNL) with promoting the commercialization of LEDs, or solid-state lighting (the broader category of lighting into which LEDs fall; see EBN Vol. 16, No. 8). Energy Star product certification should help identify quality products and ensure consumer acceptance.

At the Better Buildings by Design conference in Burlington, Vermont, in February 2008, Jeff McCullough of PNNL described how radically different solid-state lighting is from any other lighting, calling it “the most disruptive technology to hit the lighting industry in 50 years.” DOE and Energy Star are trying to avoid the problems that were experienced when compact fluorescent lamps (CFLs) were introduced to the marketplace (including unrealistic expectations and poor product performance). “We’re seeking to avoid these pitfalls with LEDs,” he said.

Based on that goal, Energy Star has developed eligibility criteria for solid-state lighting luminaires (fixtures). Version 1.0 of these criteria has been through two comment drafts and was released in September 2007. The effective date for Energy Star labeling is September 2008—giving manufacturers time to test and certify products.

Comparing LED Downlights with Incandescent Light Bulbs and CFL Downlights

While the measured efficacy of incandescent and CFL downlights fall over a fairly narrow range (shown by the darker ellipses in the figure), LED downlights vary widely (shown by the larger, lighter ellipse).

The eligibility criteria for Energy Star LED luminaires include both general requirements that apply to all LED luminaires or broad categories of them and additional requirements that vary by fixture type. Among the general requirements are the following: a minimum color rendering index (CRI) of 75; color maintenance within a narrow, precisely defined range; at least 70% light-output maintenance such that after 35,000 hours of use (25,000 hours for residential indoor products); automatic controls to ensure that residential outdoor luminaires greater than 13 watts are turned off during daylight hours; minimum power factor requirements of 0.70 (residential) and 0.90 (commercial); a Class A sound rating for the power supply; and a three-year warranty.

The table above shows the near-term application-specific Energy Star criteria for light output and efficiency. According to McCullough, over the next three years there will be a “convergent ratcheting” of the efficiency requirements to 70 lumens per watt. This ratcheting of performance standards will be possible because of the speed at which improvement is occurring. DOE raised its performance targets three times in the development of a 2009-2014 program plan for LEDs (published in March 2008) because products are “outperforming the projections,” he told EBN.

To carry the Energy Star label, LED luminaires must have been tested by an independent, third-party, DOE-approved laboratory. There are currently two laboratories that do most of the testing, but PNNL is working hard to get other laboratories geared up and approved for this work. Testing laboratories will procure three samples of each luminaire through normal market channels.

In addition to advancing LED lighting through the Energy Star program, DOE operates the Commercially Available LED Product Evaluation and Reporting (CALiPER) Program, which tests commercially available LED products and offers objective information on performance to support the industry and discourage low-quality products. PNNL has tested more than 70 LED luminaires and has found a wide range of performance. Among 13 LED downlight products tested to date, for example, efficacies ranged from 11 to 61 lumens per watt (see figure).

– Alex Wilson

For more information:

U.S. Department of Energy
Solid-State Lighting, Building Technologies Program
www.netl.doe.gov/ssl

April 1, 2008

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