Abstract: Enclosure for an illuminating fixture used in operating rooms. The enclosure comprises an upper enclosure section and a lower enclosure section which are heat insulated from each other. The lower section contains an opening for the transmission of light from the light source enclosed in the fixture. The inner surface of the lower section has good reflection characteristics for infrared light. The inner surface of the upper section has good characteristics for absorbing infrared light. The outside (back) surface of the upper section has good characteristics for emitting heat.