An enclosure containing heat-producing equipment includes an air inlet for admitting air from an environment containing the enclosure. The equipment is situated relative to the air inlet such that the air absorbs heat from the equipment, increasing the temperature of the air. An air-to-liquid heat exchanger is mounted on an outside surface of the enclosure adjacent to an air outlet. The heat exchanger is connectable to an external cooling source such that heat from the heated air exiting the enclosure absorbed by the heat exchanger is expelled outside the environment containing the enclosure.