Quantification of Building Envelope Heat Losses on a District Level for Comparative Renovation Strategies Assessment

A renovation wave calls for an integrated, participatory, and neighbourhood to neighbourhood approach tailored to the local environments. This can be hindered by the lack of geometric and performance input data about the existing building stock. Depending on the Level of Detail (LOD) of buildings in national registries the calculation results for heat loss and energy performance differ. This paper aims to analyse the impact of LOD on heating energy demand (HED) and energy performance value (EPV) using existing data from the building registry and digital twin model. As a rule, compared to the calculations based on project data or to the measured energy consumption, the calculations based on the LOD building geometry overestimate the HED and EPV. When comparing different LOD, using the same building sample, the difference between heating energy demand (HED) and energy performance value (EPV) ranges from 1% to 57% and 1% to 41% (complex geometry) or from 2% to 7% and 2% to 5% (unsophisticated geometry) accordingly. The results exhibit a good correlation of the discrepancy between the difference in the shape of LOD and the building in the reality and show that the more complex the shape of the buildings, the more important it is to use highest LOD possible. Pooling the building envelope heat loss calculation on a district level improves accuracy on average allowing better assessment of comparative renovation strategies.