Environmental impact assessment of Swiss residential archetypes: a comparison of construction and mobility scenarios

Environmental performance assessment of the built environment tends to focus mostly on operational final energy consumption of buildings located within a specific context. Such a limited scope prevents broader usability of findings in practice. In Switzerland, the ‘2000-W society’ vision provides a theoretical framework towards energy transition. Intermediate targets for 2050 relate to an extensive assessment incorporating environmental impacts of construction materials and use of a building, and of induced mobility of its occupants. Accordingly, it becomes crucial to gather information about the current building stock performance and its transition potential. The paper aims at contributing to the sustainability transition debate by providing a comparative assessment of retrofitted and new residential buildings representative of the Swiss building stock. A direct output could constitute in establishing a reliable reference dataset to support practitioners’ or lawmakers’ future decisions. The novelty of the study relies on two aspects: (1) on adopting an interdisciplinary approach to propose an overview of the current status and transition potential of the built environment, and (2) on building a methodology able to extrapolate results for large-scale studies of neighbourhoods or larger built areas. Based on the definition of four building archetypes, this study assesses four scenarios decomposed into four to six variants. The scenarios consist in varying the building energy-performance, while the variants implement different locations—among urban, peripheral and rural areas—and different passive or active strategies. Results are expressed in terms of non-renewable primary energy consumption and global warming potential. They highlight in particular the performances of renovation projects that can decrease the impacts of current building stock by 75 to 85%, the effect of high-energy performance on embodied impacts, the high-level of performance of multi-family houses with 37% lower impacts compared to those of single-family houses and the significant impact of mobility (around 50%).