Life cycle assessment of clustered buildings with a similar renovation potential

Purpose The purpose of this research is to estimate the renovation potential of a city's building stock and evaluate the environmental impact reduction and greenhouse gas emission reduction realized by clustered renovation. These reductions are compared to the climate goals for 2050 by the city of Leuven, i.e., 81% reduction in CO2-eq. compared to 2011 to support the development of an optimal renovation strategy for the city. Methods The building stock of Leuven is analyzed and subdivided into various clusters of buildings with a similar renovation potential. This paper presents the existing status of one cluster consisting of terraced buildings built between 1946 and 1970 and assesses its required renovation measures using a life cycle approach by applying the Belgian LCA method for buildings. The environmental impact of this cluster and the potential reductions obtained by the renovation are upscaled and compared to the city climate goals. Based on these results, the total impact of this cluster on the greenhouse gas emissions of Leuven is calculated and the most impactful renovation measures identified. Results and discussion The results reveal that renovating the walls, floors, and roofs of the houses in this cluster in Leuven (representing ca. 5% of the stock) can lead to a reduction in CO2-eq. emissions of 0.9 to 1.9% compared to the emissions by Leuven households in 2011. This estimate ignores the improvement of the airtightness and the renewal of heating systems. So, higher reductions may be possible. The renovation impact of each of the building elements is evaluated separately, indicating that the highest improvements can be obtained by improving the insulation level of the walls. A sensitivity on the original state of the building has been performed by assuming the absence of (a small) insulation layer in the original roof state. This reveals a significant higher CO2-eq. reduction potential due to renovation. Conclusions The results demonstrate the appropriateness of the clustering approach in estimating the greenhouse gas emissions of a certain housing type and the potential contribution of renovating these to reduce the city greenhouse gas emissions. By extending this analysis to all identified clusters, the full potential of renovating the housing stock in Leuven can be estimated and can help in setting priorities in the overall goal to reduce greenhouse gas emissions.