A unit arrangement having a receiving housing, in particular a switchgear cabinet, in an interior of which electrical units are accommodated and having a cooling device which is in air-conducting communication with the interior of the receiving housing via at least one air inlet and at least one blower aperture, and a cooling operation monitoring device. A requirement-orientated control of the cooling operation is possible when the cooling operation monitoring device has an inlet temperature sensor which measures a temperature of the air to be cooled which is supplied to the cooling unit via the air inlet. An outlet temperature sensor measures a temperature of the cooled air which is supplied to the interior of the receiving housing via the blower aperture. A computing unit of the cooling operation monitoring device determines a temperature difference between the temperature measured by the inlet temperature sensor and the outlet temperature sensor.