1 Long-Term Performance of Screwbase Compact Fluorescent Lamps Paper # 19 Conan O’Rourke and Mariana G. Figueiro, MS Lighting Research Center, Rensselaer Polytechnic Institute 21 Union Street, Troy, NY, 12180 Abstract Over the past several years, screwbase compact fluorescent lamps (SCFLs) have been promoted as replacements for incandescent lamps in interior and exterior luminaires. One commonly quoted benefit for SCFLs is longer life. The lamp industry uses the 3-hour-on/20-minute-off switching cycle to determine rated lamp life. However, in residential applications, lamps are switched on and off at different rates and lamp life for SCFLs depends on how frequently they are switched. An experiment was conducted to investigate the effects of different operating cycles on the life of SCFL products. Data for 11 different SCFL products from six different manufacturers operating in six different cycles are reported. This paper discusses performance characteristics of SCFL and factors affecting fluorescent lamp life. Differences between SCFL products and linear fluorescent lamps are also discussed.