Data source integration approach for the definition of new reference buildings: The Italian case study

Reference Buildings (RBs) play a crucial role in assessing building energy performance and developing energy-efficient policies. However, identifying RBs is often challenging due to the complexity and heterogeneity of building stocks. In this study, a comprehensive analysis was carried out to define RBs for the Italian residential sector, focusing on key building parameters such as climatic zones, construction periods, number of stories, building units, net floor area, energy use, and energy systems. By integrating different data sources about the Italian building stock, some used for the first time for this purpose, the study addressed gaps in previous research and marked the first attempt to define RBs across all six Italian climatic zones. The analysis shows that one-story and two-story buildings and those in the 60–100 m 2 range are the most common nationwide. Larger building units are more prevalent in warmer climatic zones, while smaller solutions are more typical in colder climatic zones. Traditional energy systems, such as standard boilers, are predominant in older buildings, but newer constructions show a clear shift toward energy-efficient systems, including condensing boilers and heat pumps. These trends are consistent across all climatic zones. The resulting reference models provide crucial insights for improving energy performance in the Italian residential sector, supporting future research and guiding energy policy implementation.