Analysing the inequitable energy framework for the implementation of nearly zero energy buildings (nZEB) in Spain

Most countries from the European Union work towards a low-carbon horizon in the building sector. As for Spain, the last modification of the Spanish Building Technical Code in 2020 establishes that every building ensuring the fulfilment of the regulation will obtain the category of nearly zero energy building. However, the limit values of the thermal properties of envelopes only distinguish 6 variations according to the winter climate zone. For this reason, this study analyses the potential risk of the existence of energy inequalities due to the fulfilment of the regulation as regards energy efficiency in Spain. A total of 48,786 energy simulations were performed by taking the 8131 municipalities of the country into account, as well as the previous and current regulation. The results considered heating and cooling demands, cluster analyses, and their impact on population, showing that the improvement of thermal properties could guarantee buildings with a better energy performance for a greater number of inhabitants. There was, however, a limitation in the current climate classification, so a more detailed climate classification with new limit values is required. The results also showed the limitations of use of the thermal transmittance to reduce the cooling energy consumption. This study could be the starting point to establish new regulatory parameters to reduce energy consumption equitably, considering the importance of cooling consumption in future climate change scenarios.