Recessed downlights are one of the most popular fixtures used for lighting commercial buildings. The vast majority of these fixture use incandescent lamps in sizes ranging from 50 to 150W. Because cost and energy efficiency are a growing concern in the lighting design process, fixtures using compact fluorescent lamps (CFLs) have made significant inroads into the incandescent market. While providing high efficiency, these fixtures also reduce operating cost. CFLs have an efficacy about four times that of incandescent lamps; they also last about 10 times longer, thus providing maintenance savings.