Buildings consume about 40% of total final energy in Europe, and those built before 1980 represent 95% of this energy consumption. The low renovation rate of building stock (1% per year) means that boosting energy efficient buildings’ retrofitting is the only way to reach EU’s “20-20-20” targets. The higher impact will be achieved through interventions in non-residential buildings, as their energy consumption is 40% higher than in residential buildings, being the public buildings more than 30% of the non-residential buildings in EU. A2PBEER will develop a systemic energy efficient buildings’ retrofitting methodology for Public buildings and will take advantage of synergies derived from interventions at district level. A2PBEER methodology will include already available building solutions and more innovative ones developed by the project: a “high performance envelope retrofitting”, based on an external and internal super-insulated (VIP–Vacuum Insulated Panels) façade retrofit and smart windows, “smart lighting systems” combining LED and natural light, and the “Smart Dual Thermal Substation”, a new approach to district heating based in smart grid functionality and integrating heating and cooling. A “kit-concept” will be applied in the development of new solutions in order to deploy adaptable and affordable solutions. The methodology and developed kits will be demonstrated and validated through three real retrofitting deployments, covering main climatic areas in Europe (continental, oceanic and Mediterranean), different types of Public districts and main Public end-uses. Moreover, the replicability of A2PBEER results will be further validated through three complementary virtual projects covering additional climatic areas and end-uses. A comprehensive “Train the Trainer” and an innovative market approach will allow results be transferred to all key players of the value chain, with special focus on SMEs, and the transferability to social housing will be also addressed.