Empirical assessment of life cycle GHG emissions of historical buildings with heritage values

Historic building stocks have important cultural and aesthetic values embedded in the designs and urban environments. Careful renovation, maintenance and management practices are needed to ensure that heritage values in historic buildings are not lost. However, there is little empirical evidence of the life cycle processes from renovation practices and the greenhouse gas emissions (GHGe) associated with them. This study presents a life cycle-based assessment of 56 historical buildings in Denmark. Results show GHGe in the range of 3–178 kg CO 2 eq/m 2 and a median of 66 kg CO 2 eq/m 2 . These numbers represent the production, construction waste treatment and final end-of-life modules of the building life cycle. Maintenance logs from the 56 case study buildings over a period from 2015 to 2023 provide unique insights into real maintenance-repair-replacement activities. These numbers show, in general, negligible GHGe to the overall result, although a few of the replacement activities show to be significant. Future logging and improved granularity in modelling between maintenance, repair and replacements could provide valuable insights for research and practice. Post-renovation median energy use for heating and hot water is found at 123 kWh/m 2 /year for residential- and 119 kWh/m 2 /year for non-residential buildings. The heating technology in place shows to be the most important determinant for the life cycle GHGe from the renovated buildings, pointing to the importance of effective energy management and energy use practices. The analysis of the results highlights the important dimensions of a building’s characteristics, condition, and transformative use as key elements in determining the GHGe from renovation activities.