The central Europe is a highly urbanised area with a huge stock of existing public and private buildings with low energy efficiency. Great efforts are necessary to overcome the problem of energy consumption. To reach the goal of a nearly-zero energy demand buildings there is a great need for new techniques, methodologies and investments. The overall objective of the project CEC5 is the promotion of energy efficiency and exploitation of renewable energy sources through application in public buildings. At EU level, the Directive 2009/28/EC on Renewable Energy Sources (RES) and the Proposal on the Recast of the Energy Performance of Buildings Directive (2002/91/EC) define the framework for related actions for the next years in the fields of RES and energy efficiency (EE). The project will directly address all these elements in a combined way.