Indicating the environmental performance of the residential building stock in EU-25 countries by LCA

Beside being used for evaluating the environmental impacts of new buildings, Life Cycle Assessment (LCA) is also a suitable instrument for assessing existing buildings. As knowledge about the environmental performance of the residential building stock in EU-25 countries was rather limited, the research project "Environmental Improvement Potentials for Residential Buildings" (IMPRO-Building) was initiated by the European Commission (IPTS). A main objective of the project was to outline the current environmental performances of residential buildings in the EU-25 throughout their entire life cycle. Furthermore, an assessment and evaluation of environmental improvement options for both new and existing buildings from an European perspective were conducted. For this purpose, the existing residential EU-25 building stock was clustered in major building groups such as single-family houses or high-rise buildings and aggregated, using geographical zones within Europe. For efficiently addressing the environmental relevant aspects of various building types, a highly sophisticated generic life cycle model of buildings has been developed. It was used to identify environmental hot spots of new planned and existing buildings and to evaluate improvement options of more than 50 building types in a consistent way. As the general options for decisions for existing and planned buildings vary, their LCA system boundaries differ. The model for 'existing buildings', based on retrofit actions, considers only the use phase, retrofit measures and demolition. In contrast, the model for 'new buildings' includes the entire construction phase, the use phase and the demolition of the building. An overview on the identified residential building types in the EU-25 will be presented including exemplary results on their environmental performance for Southern, Central and Northern European countries. Besides, the methodology and the parameterized models developed for an efficient and consistent life cycle modeling of the related various building types will be described.