Thermal building simulations (TRNSYS) were linked to nodal airflow network simulations (COMIS) for a detailed ventilated double-skin facade performance calculation. Simulation results were compared with measured data from an office building in Lisbon for a sunny and an overcast day in September 2005. The simulation results of surface and air temperature show good agreement with measurements. The simulation model can be used to reduce surface temperatures by using different materials for the roller blind that is positioned in the cavity of the double-skin façade. The model can further be used to reduce the high peak cooling loads during the summer period by controlling the exhaust airflow. This has potential to result in significant energy conservations and a reduction in systems cooling size.