We report data for a pair of singlestack all-phosphorescent 15×15 cm2 organic light emitting-diode (OLED) light panels with high efficacy, long lifetime, and very low operating temperature: Panel 1 has 62 lm/W efficacy, CRI = 81 and lifetime to LT70 = 18,000 h at 1000 cd/m2, while Panel 2 has 58 lm/W efficacy, CRI = 82 and lifetime to LT70 = 30,000 h at 1000 cd/m2. Operating at a higher luminance of 3000 cd/m2, Panel 2 has 49 lm/W efficacy with lifetime to LT70 = 4000 h. Excellent panel lifetime is enabled by a stable light blue phosphorescent materials system. Panel temperatures are within 10°C of ambient temperature at 3000 cd/m2. Panel 2 was further used as a building block to demonstrate an all-phosphorescent OLED luminaire for under-cabinet lighting applications. Operating at approximately 3000 cd/m2, the luminaire delivers 570 lm with 52 lm/W total system efficacy, CRI = 86 and CCT = 2940 K.