This study presents the results of the actual thermal behaviour of a multi-storey naturally ventilated double skin facade. Governed by lack of experimentally measured data, a field of detailed measurements were performed during the 2013/2014 season in the office building located in Belgrade, Serbia. The uniqueness of this building is that the first facade layer is made in the tradition manner. Apart from studying classical environmentally influenced air cavity behaviour, the methodology incorporates a detailed analysis of the air cavity enthalpy flow. The main purpose of this research is to examine the current state of the building facade and how it affects energy performance. To this effect, measurement data was used in order to analyse transmission losses and gains and to quantify enthalpy change of the cavity air linked to the airflow established within the facade. Analyse of the transmission losses and gains were described by a series of diagrams of vertical and horizontal temperatures trends for selected typical days in each regime. For investigation of the natural ventilation potential, an adequate indicator based on the enthalpy change was established. Overall, the experiment results highlight that the use of a double skin facade does not necessarily reduce energy consumption. (C) 2014 Elsevier B.V. All rights reserved.