EASEE aims at developing a tool-kit for energy efficient envelope retrofitting of existing multi-storey and multi-owner buildings which combines novel design and assessment strategies, modular prefabricated elements, advanced insulating materials and new scaffolding-free installation approaches, to reduce energy demand, minimising the impact on occupants while preserving the façade original appearance.Particularly, the project will target residential buildings with cavity walls built before 70’s. These buildings require façade retrofitting for technical reasons or improvements in the insulation and energy efficiency to reduce the energy demand, while the conservation of the building appearance is necessary.EASEE will focus on the 3 main components of the envelope that influence the energy performance of multi-storey building, namely the outer façade, the cavity walls and the interior envelope, by developing innovative and easy to implement solutions. A new range of specific solutions will be developed within the project, that will be combined according to the characteristics of the building to be retrofitted as well as to other non technical parameters as for example cost and location of the building, also within the district.The proposed approach will allow for an overall retrofitting cost over the whole life cycle and for a total cost of ownership up to 120 Euro/m2 allowing a return on investment below 7 years. EASEE will reduce overall retrofitting duration and optimise the worksite in general with direct benefits for the workers and the occupants, while creating new business opportunities worth 4 BEuro in energy efficient retrofitting of existing buildings by the 5th year after project completion, mobilising new cooperation schemes between Les and local SMEs through licensing mechanisms. This is fully in line with the expected impact in the call and with the overall goal of the EeB PPP under the recovery plan.