The energy upgrading of the building of the Regional Unit of Pella as a public building aims to achieve the national targets set in the National Action Plan for Energy Efficiency. Furthermore, the aim is to exploit the potential for energy savings and improvement of energy efficiency in the building sector, with the building of the central administration of the Prefecture of Pella being an example for the mobilisation of all public buildings in the area. The intended results of the interventions concern the reduction of the energy consumption of the building and the parallel reduction of greenhouse gas emissions, namely a reduction of CO2 emissions from 873 kgm2 to 671 kgm2 through the improvement of energy efficiency and the use of RES and consequently the drastic reduction of operating costs.