Digital models for the decarbonization of the built environment

The building sector is one of the main contributors to global greenhouse gas emissions, making the energy renovation of the existing building stock a priority for achieving decarbonization targets, particularly in Europe where most buildings are already constructed. This stock includes both historical and modern heritage, often characterized by architectural, cultural and regulatory constraints that complicate intervention processes. In this context, digitalization offers significant potential to support more informed and effective renovation strategies, although its application remains fragmented and not fully aligned with the needs of different stakeholders. This research investigates how digital models can support the decarbonization of existing buildings, focusing on their role within renovation workflows. The study is structured around three research questions: how data acquisition methodologies influence the construction of digital models; which characteristics digital models must possess to support the different phases of energy retrofitting; and how the usability and interoperability of BIM models can be ensured for actors with diverse skills and objectives. The research adopts a combined theoretical and experimental approach, based on three case studies representative of different building types and intervention goals. The first case study focuses on historical heritage and investigates the development of geometric models to support knowledge and documentation processes, analysing the transition from data acquisition to representation. The second case study, addresses modern heritage and explores the use of informative models to support the comparison of renovation strategies, integrating energy analysis and design communication while considering conservation requirements. The third case study, examines a design-oriented workflow in which digital models support renovation interventions based on prefabricated components, linking modelling activities with technical development and construction processes. Across the three case studies, workflows are defined and compared through the phases of data acquisition, data processing and integration, and modelling for different purposes. The research contributes to the definition of a flexible and integrated methodological framework for the development of digital models supporting renovation processes. By aligning data acquisition strategies, modelling approaches and intended uses, the proposed framework enhances the effectiveness, replicability and scalability of digital workflows.