Residential LED Down Lights

The objective of this study is to assess the status of the light-emitting diode (LED) recessed can lighting and to measure any incremental energy and demand savings over their pin-based compact fluorescent and halogen counterparts. Photometric and power tests conducted in the Southern California Lighting Technology Center (SCLTC) demonstrate the differences and similarities of the baseline (fluorescent and halogen) vs. measure (LED) cases. To supplement the tests conducted at the SCLTC, a field study was conducted to understand how residences use their kitchen overhead lighting. This study consisted of monitoring 60 houses. Of the 60 houses, it was found that there were two predominant lighting configurations: kitchens with only overhead lighting and kitchens with both overhead and under cabinet lighting. The data was used to help gain an understanding of the yearly operation of the overhead lighting in kitchen applications. The photometric and power data obtained through lab testing was combined with hourly usage figures to obtain energy savings, demand savings, and efficacy figures for the technology. Recent advances in LED technology have made them brighter and more efficient, thereby expanding the application of the LED to the various lighting markets. In addition to using high efficiency LED chips, some manufacturers have improved efficiency of the required ACDC conversion process. This study assumes that the end user operates the LED lamp in the same way as the fluorescent and halogen lamps. The measured lumen output of LED lamps ranged from 126 lumens (lm) to 1456 lm. The 26 Watt (W) pin-based fluorescent was tested both as a bare lamp and inside a recessed can fixture. The measured lumen output of the Compact Fluorescent Lamp (CFL) inside of a recessed can was 447 lm; most of the LED lamps exceeded this light output. Test results demonstrate that there are some LEDs that can compete with both the CFL and halogen baselines. Since there was a range of tested efficacies and lumen outputs, the baseline cases were normalized to estimate the CFL and halogen wattage at different lumen outputs based on efficacy. Through the field evaluation, homes with only overhead lighting (Kitchen Configuration A) used it for 1180.2 hours annually. Homes with both overhead and under cabinet lighting (Kitchen Configuration B) used the overhead lighting for 963.9 hours annually. Combined with the average demand savings acquired through lab testing, it was found that on average tested LEDs save 16.47 kilowatt hours (kWh) annually in Kitchen Configuration A and 13.45 kWh annually in Kitchen Configuration B over the 26W CFL. The average tested LEDs save 38.61 kWh annually in Kitchen Configuration A and 31.53 kWh annually in Kitchen Configuration B over the 60W halogen. The LEDs tested had manufacturer ratings for wattage that ranged from 5 – 38W.