Abstract: A luminaire includes a fixture including at least one light source, a power supply mounted to the fixture for supplying power to the light source, and circuitry in communication with the power supply for controlling the power supplied to the light source dependent upon an ambient temperature, such that the power supplied to the light source is reduced when the ambient temperature falls below the threshold ambient temperature in order to limit the power supplied to the light source while an output of the light source remains substantially constant despite the limited power supplied. A system for indicating when maintenance is required on one or more luminaires in a building by sensing ambient temperatures and determining a difference between the ambient temperatures sensed and providing an indication signal that the determined difference between the ambient temperatures is at or above a threshold difference.