To date, the implementation of energy performance certificates (EPCs) varies significantly across Member States in terms of scope and available information, resulting in some cases in limited reliability, compliance, market penetration or acceptance by the users. Aspects like smart dimension or the interaction with the district energy system are only insufficiently covered in current EPC schemes. In order to become a catalyst for energy renovations, the next-generation EPC must provide an improved and more reliable service to the end-users. X-tendo will develop and test next-generation EPC features in 9 countries around Europe covering 40% of the EU building stock, and assist the implementation of the features into the existing EPC schemes. This will support the public authorities in these regions in the recasting of the existing EPC schemes and lead to increased rates of application of EPCs as well as renovation activities in a remarkable number of defined regions across EU. The main tool to support public officers is the X-tendo toolbox, that considers the strengths and weaknesses of current EPC schemes according to their effect on the market, end users and the society as a whole, and looks into possible additions and improvements to these schemes. The modular structure of the toolbox covers different features of innovative indicators as well as innovative data handling approaches. The features are smart readiness indicator, comfort, outdoor air pollution, real energy consumption, district heating, EPC databases, building logbook, tailored recommendations, financing options, one stop shops. A selection of relevant test projects will demonstrate the potential of the developed toolbox to deliver more reliable next-generation EPC schemes across the EU. By enhancing innovative aspects in the X-tendo toolbox and disseminating the toolbox throughout Europe, the innovative aspects will gain ground in a quick and easy way. The modular structure also enables energy agencies to choose for a gradual implementation of all aspects, as it ensures the possibility of a stepwise innovation of EPC schemes, without risking lock-in effects as all the modules of the toolbox can interoperate. X-tendo promotes systems to create better, more advanced, more useful and more engaging EPCs. As such, the X-tendo toolbox will increase the trust in the energy performance assessment and certification, that will likely result in more EPCs issues, on both voluntary and mandatory basis. The increased trust in the certificate and the more useful information it contains will lead to an increased renovation rate, ensuring extra jobs in the construction sector and a boost for economy.