RES4BUILD will develop renewable-eneRRES4BUILD develops renewable energy-based solutions for decarbonising the energy used in buildings. The approach of the project is flexible, so that the solutions are applicable to a wide variety of buildings, new or renovated, tailored to their size, their type and the climatic zones of their location. In the heart of the solution lies an innovative multi-source heat pump with a cascading configuration, including a magnetocaloric (bottom cycle) and a vapour compression heat pump (top cycle). The heat pump will be combined with other technologies in tailored made solutions that suit the specific needs of each building. These technologies will be selected on a case by case basis from a mix of standard equipment available in the market and from innovative components that will be specifically explored within the project. The innovative technologies include innovative collectors that integrate in one panel photovoltaic cells and solar thermal energy collectors (PV/T) and borehole thermal energy storage (BTES). For all solutions, advanced modelling and control approaches will be developed and will be integrated in a Building Energy Management System, allowing the users to select their objectives and to optimise the use of the system accordingly, allowing the activation of demand response and the exploitation of the full value of smart appliances and smart charging of electric vehicles. The project adopts a co-development methodology, where the end-users and other relevant stakeholders are engaged in an interactive process, where a RES$BUILD system is designed for their buildings with their active participation. In parallel, a full life cycle assessment and life cycle costing analysis will be carried out, showing from an early stage the real impact of each proposed design. The diverse consortium and the dedicated exploitation tasks will connect the project with the market, paving the way for wide application of the developed solutions.