Building renovation processes towards low greenhouse gas emissions and energy use

Large residential areas in Sweden and elsewhere are facing a need for renovation. Swedish buildings from the record year era (1961 – 1974) are now 40 – 55 years old and in many cases in need of extensive renovation measures. This need for renovation could be seen as an important opportunity to achieve overarching sustainability target levels and to perform renovation with a holistic approach. This thesis is part of the research project " Management of environmental aspects in the renovation process " aiming at creating support for the formulation and achievement of adequate environmental targets that relate to overarching Swedish Environmental Quality Objectives. The overall aim of the thesis is to contribute to an understanding of the current situation of environmental management in renovation processes. The scope of this thesis is limited to the aspects energy use and greenhouse gas (GHG) emissions from energy use and material production. This thesis contributes to this aim with a stepwise procedure for evaluation of measures together with a proposal for target levels for three environmental aspects. The three aspects are: operational energy use, GHG emissions due to total energy use for building operation, and embodied GHG emissions due to production of building materials. The first paper appended to this thesis investigates how six Swedish property owners performed renovation projects and how sustainability aspects are handled. From this paper it can be concluded that the way Swedish property owners address environmental aspects in renovation projects needs to be improved. Furthermore, the conclusion can be drawn that the main barrier (except economic ones) are characterized by lack of knowledge about overarching objectives and what aspects define a sustainable built environment. The second paper assesses embodied GHG emissions due to material production for the totality of measures needed to reduce operational energy demand per unit heated floor area by 50% compared with 1995. On a national level, embodied GHG emissions are estimated to be 12% of the reduction of GHG emissions achieved by operational energy demand reduction. Thus, while embodied GHG emission constitute a relatively small share of the total GHG emissions, the fraction is not insignificant, suggesting that embodied GHG emissions are relevant to consider in renovation projects. The final paper appended to this thesis uses a case study building to illustrate a working procedure to identify project-specific target levels for the three aforementioned environmental aspects. In addition, it identifies indicative improvements necessary for …