Methodological aspects of environmental assessment of buildings

Abstract: The built environment contributes extensively to the overall environmental impact of society. An increasing number of tools have been developed worldwide for comprehensive environmental assessment and rating of buildings in order to make the building sector more sustainable. These tools are expected to drive and facilitate future environmental improvements and market transformation in the sector. This thesis explores different methodological aspects in tool development using experiences from two large Swedish projects, the EcoEffect and ByggaBo tools, which were developed with a high level of stakeholder participation in order to be of practical use in the building sector. The methodological aspects explored and discussed here include an approach for systematic selection of assessment aspects (energy use, indoor air quality, etc.) in tools (Paper 3), and a systematic procedure for selecting practical indicators using theoretical (e.g. validity/environmental relevance) and practical (e.g. costs) criteria (Papers 2 and 3). An approach for simple communication of complex results is presented with examples from 26 multi-family buildings (Paper 4). This approach allows a building’s ‘environmental efficiency’ to be presented in one diagram, without weighting the two distinct assessment areas energy use and indoor environmental quality. Paper 5 discusses the contextual issue of internal use of environmental indicators in property management organisations through reviews of environmental performance evaluation and organisation theory literature and comparisons with actual case studies. The EcoEffect (Paper 1) and the ByggaBo tools are also compared and summarised. The case studies of real buildings and experiences from the EcoEffect and ByggaBo projects allowed data collection, calculation procedures and different practical applications of such tools to be evaluated. Poor data availability sometimes limits assessments, and improved internal routines and database developments in the building sector would allow more reliable environmental assessments. Reviews of numerous indicators in Paper 3 (and 2) and literature revealed that environmental relevance was not a key aspect when current environmental performance indicators and building rating tools were constructed. This thesis suggests that environmental relevance and systematic procedures be prioritised in order to provide robust and trustworthy tools for environmental assessment of buildings.  Recommendations, some of which are generally applicable to other environmental assessments, include selection of environmentally relevant indicators, systematic procedures for handling theoretical and practical considerations in tool development, aggregation and weighting methods, use of a life cycle perspective and inclusion of performance-based rather than feature-based indicators. Since it is likely that the information these tools provide will increasingly be used by authorities, building users, economic incentive providers such as banks, etc., the methodological developments suggested here to strengthen tool rigour are important for future tool development processes.