Peak loads in Iran's national electrical grid are always appear during summers days where a significant part of them is due to cooling systems in the buildings. In this paper a prototype Double Skin Facade (DSF) integrated into a Double Glazed Window (DGW) has been designed and retrofitted to increase the efficiency of the cooling system of a typical sunshine oriented office room. Temperature profiles on inner and outer surfaces of this office have been recorded before and after implementing this energy saving method. On the other hand, a numerical simulation was developed in order to model the behavior of the system where the inputs of the model are environmental parameters such as solar irradiation, wind velocity and ambient air temperature. The simulated model was fully validated by implementing a local experimental setup. In this research, experimental temperature profiles are compared to the model based ones to evaluate the numerical model's validity. By employing the final prediction errors the results show a good agreement between model and profiles. From energy saving point of view, thermo-graphical images showed that the designed system has the ability to save 0.27-0.42 kWhth/m(2)/day, by decreasing the air conditioning inlet temperature between 4 and 6 degrees C in summer days. Integration of the proposed DSF system into the buildings in suitable conditions, would potentially provide a nation-wide electricity consumption reduction up to 4283039.4 MWh alongside with its positive environmental benefits during hot season.