A solid-state lighting unit comprising: a solid-state array housing defining an internal compartment; at least one solid-state array module, comprising: an array of solid-state lighting elements; a solid-state lighting element control circuit; and a printed circuit board, the solid-state array module being accommodated within the internal compartment of the solid-state array housing; a rear surface of the solid-state array housing comprising a heat transfer element; and a power supply housing accommodating a power supply, the power supply housing having a front surface opposing the rear surface of the solid-state array housing, and having a chimney extending therethrough from the front surface of the power supply housing to a rear surface thereof, the rear surface of the solid-state array housing being fixedly disposed in a spaced apart relationship with respect to the front surface of the power supply housing, such that an input airflow space is defined therebetween so that, during operation of the solid-state lighting unit, ambient air flows, radially inwardly toward the central illumination axis, into the input airflow space and toward the central illumination axis of the solid-state lighting unit and exits axially along the central axis and through the chimney to facilitate removal of heat from the solid-state lighting elements, characterized in that the chimney comprises a lumen aligned along the central illumination axis, the lumen comprising a first conically shaped lumen with its base facing the rear surface of the solid-state array housing, and a second conically shaped lumen with its base facing the rear surface of the power supply housing, the first and second conically shaped lumens joined together along a generally narrower throat section. a solid-state array housing defining an internal compartment; at least one solid-state array module, comprising: an array of solid-state lighting elements; a solid-state lighting element control circuit; and a printed circuit board, the solid-state array module being accommodated within the internal compartment of the solid-state array housing; a rear surface of the solid-state array housing comprising a heat transfer element; and a power supply housing accommodating a power supply, the power supply housing having a front surface opposing the rear surface of the solid-state array housing, and having a chimney extending therethrough from the front surface of the power supply housing to a rear surface thereof, the rear surface of the solid-state array housing being fixedly disposed in a spaced apart relationship with respect to the front surface of the power supply housing, such that an input airflow space is defined therebetween so that, during operation of the solid-state lighting unit, ambient air flows, radially inwardly toward the central illumination axis, into the input airflow space and toward the central illumination axis of the solid-state lighting unit and exits axially along the central axis and through the chimney to facilitate removal of heat from the solid-state lighting elements, characterized in that the chimney comprises a lumen aligned along the central illumination axis, the lumen comprising a first conically shaped lumen with its base facing the rear surface of the solid-state array housing, and a second conically shaped lumen with its base facing the rear surface of the power supply housing, the first and second conically shaped lumens joined together along a generally narrower throat section.