From high-energy demands to nZEB: the retrofit of a school in Catalonia, Spain

Since existing buildings are responsible for almost 40% of the energy consumption, a major focus in the construction sector is represented by building energy-saving retrofits. Considering the limited current economic possibilities in the construction market, the retrofit of existing buildings has become a target for both private actors and public administrations in most of European countries. In this context, the province of Catalonia in Spain is defining strategic plans and guidelines to help energy retrofits according to nZEB criteria. In this framework, the present paper evaluates the effectiveness of a series of strategies considered in the energy refurbishment of a school located in the Metropolitan Area of Barcelona. Firstly, the study reports the results of an extensive (level three) energy audit. This data is then used to create a reliable energy simulation model. A set of possible interventions is hence investigated considering technical feasibility, cost, and potential energy saving and indoor comfort benefits. Results show the actual possibility of reaching the nZEB standard at the end of the refurbishment of this high-energy consuming building. Finally, the case study is discussed as a valuable example for promoting energy retrofits in Catalonia and beyond.