Assessing buildings' absolute environmental sustainability performance using LCA focusing on climate change impacts

The building sector is ofmajor concern when seeking to reduce the environmental impact of our society. A common tool often used in certification systems for quantification of environmental impactsis Life Cycle Assessments (LCAs). LCAs are traditionally used for relative comparisons, i.e. to assess whether one product orservice performs better than another. Recently, a method for absolute evaluationsbased onthe Planetary Boundaries, wascoupled withLCA in order to define the boundary between environmental sustainability and unsustainability. In this study Planetary Boundaries-based Life Cycle Impact Assessmentmethodhasbeen applied to a case study of six single family stand-alone dwellings to assess whether these buildingscan be considered absolute sustainablerelative to the Planetary Boundaries. The results from the assessment indicate that irrespective of the design strategy used for the six houses and future increase in the use of renewables for electricity and heat production,it is unlikely that any of these houses can be regarded as sustainablein absoluteterms. This underlinesthat more radical changes are needed in the way buildings are constructed and used in order for buildings to become environmentally sustainable.