The physical object of the operation concerns energy-saving interventions in the building complex which houses the school units of the 1st and the 1st High School of Igoumenitsa with a surface area of 3241.67 m², as well as the technical infrastructure costs required by the implementation of the technical infrastructure to connect to the network of Dendes.The existing situation, the building complex of the 1st High School of the 1st Lyceum, is a municipal building with low energy efficiency, in which there is a large potential saving. Energy-saving interventions based on the final study of subproject 1 are expected to be implemented within 18 months, apart from the obvious reduction of the operating costs of the building complex, reducing CO2 emissions, thermal comfort, optimisation of lighting by achieving visual comfort, minimising heating and cooling loads and improving quality of life as the environmental conditions within the spaces are properly regulated, so that students and teachers feel comfortable and pleasant.