Renovation and reconstruction of built heritage. criteria, instruments, and means for energy savings at urban scale.

The building sector accounts for approximately 40% of energy consumption and 36% of greenhouse gas (GHG) emissions. Renovation and reconstruction are two of the main strategies to mitigate the energy use of existing building heritage and take action at the urban scale. Starting from GIS data concerning an Italian case study of the second half of the 20th century, a scenario-based analysis approach was taken to evaluate the energy savings of seven different renovation and reconstruction scenarios. The proposed methodology combines the municipal geodatabase with a building database of a specific period from archival research on building permits. Subsequently, data processing in Grasshopper allows the semi-automatically transforming of the 2D GIS geometric polygons into 3D models characterized by proper morphology, approximate window accuracy and construction information. In this way, building elements featured by material parameters (density, thermal conductivity, etc.) are used inside the two environmental analysis plugins, Ladybug and Honeybee (Ladybug Tools LLC), to achieve the building block energy modelling. The thermal model provides the energy consumption of the existing residential block and simulates the renovation and reconstruction scenarios. These findings are employed as part of a decision-making urban regeneration platform that compares demolition with reconstruction and renovation, considering economic, social, structural safety, obsolescence, and environmental aspects.