A lighting system or luminaire can comprise two environmentally sealed housings. One of the housings can house one or more light emitting diodes. The other housing can house a driver for supplying electricity to the light emitting diode or diodes. The housings can be nested together. For example, one of the housings can extend partially into a cavity of the other housing. A portion of the cavity can remain unfilled when the housings are nested, to provide an air gap between the two housings. The air gap can be environmentally exposed, for example exposed to moisture when the lighting system is mounted outdoors.