New and efficient luminaires have been designed for compact, twin tube-type fluorescent lamps. One important example of these new fixture applications is the 1*1 ft luminaire with three 18 W high lumen twin tube fluorescent lamps. Performance comparisons with this luminaire type have been made using different 18 W lamps operating on preheat and rapid start-type ballasts. The preheat (switch start) measurements were made at 240 V and 50 Hz using single lamp reactor type ballasts, and the rapid start measurements were made at 120 V and 60 Hz using three-lamp electromagnetic and electronic ballasts. In addition, comparisons are made against an older technology 150 W incandescent downlight fixture with approximately the same light output level indicating the substantial improvement in system photometric performance for these new compact fluorescent light sources.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>