U.S. Department of Energy - Energy Efficiency and Renewable Energy

Building Technologies Office – Market-Based Programs

LED PAR38 Lamps

The following CALiPER reports provide detailed analysis of LED PAR38 lamp performance, covering basic performance characteristics as well as subjective evaluation of beam, shadow, and color quality. Pending reports will offer analysis on flicker, dimming and power quality characteristics; stress testing; and lumen and chromaticity maintenance. These reports are intended to educate the industry on market trends, potential issues, and important areas for improvement.

  • Application Summary Report 20: LED PAR38 Lamps
    An initial sample of 38 LED PAR38 lamps and 5 halogen and CFL benchmarks underwent photometric testing according to IES LM-79-08. CALiPER Application Summary Report 20, which also includes an addendum covering 6 additional LED products and 3 additional benchmarks that were similarly tested, focuses on the basic performance characteristics of the LED lamps compared to the benchmarks, as well as performance relative to manufacturers' claims. (34 pages, November 2012—Addendum September 2013).

    Following the initial CALiPER report on LED PAR38 lamps, several additional special investigations were initiated. The results of these investigations are divided into four reports, each of which includes new data for all or a subset of the products described in Application Summary Report 20. Information on basic performance characteristics—such as efficacy, lumen output, and beam angle—is generally not repeated in any of the special investigation reports.

    • Report 20.1: Subjective Evaluation of Beam Quality, Shadow Quality, and Color Quality for LED PAR38 Lamps
      This report focuses on human-evaluated characteristics, including beam quality, shadow quality, and color quality. Using a questionnaire that included rank-ordering, opinions on 27 of the Report 20 PAR38 lamps were gathered during a demonstration event for members of the local Illuminating Engineering Society (IES) chapter. This was not a rigorous scientific experiment, and the data should not be extrapolated beyond the scope of the demonstration. The results suggest that many of the LED products compared favorably to halogen PAR38 benchmarks in all attributes considered. LED lamps using a single-emitter design were generally preferred for their beam quality and shadow quality, and the IES members' ranking of color quality did not always match the rank according to the color rendering index (CRI). (31 pages, October 2013)

    • Report 20.2: Flicker, Dimming, and Power Quality Characteristics of LED PAR38 Lamps (pending)
      Dimming curves and flicker waveforms, measured at the Pacific Northwest National Laboratory (PNNL), will be presented for all of the PAR38 lamps included in Application Summary Report 20.

    • Report 20.3: Stress Testing of LED PAR38 Lamps (pending)
      A small sample of each of the Application Summary Report 20 PAR38 lamp types underwent stress testing that included substantial temperature and humidity changes, electrical variation, and vibration. The results do not directly address expected lifetime, but can be compared with one another, as well as with benchmark conventional products, to assess the relative robustness of the product designs.

    • Report 20.4: Lumen and Chromaticity Maintenance of LED PAR38 Lamps (pending)
      The lumen depreciation and color shift of 40 lamps were monitored for an extended period of time using the Lumen Maintenance Test Apparatus at PNNL.

Detailed reports are available for all CALiPER-tested products via an online search system. Older CALiPER Reports are available for download in the CALiPER archives.