Strategies for optimizing the environmental profile of dwellings in a Belgian context: A consequential versus an attributional approach

To date, many tools and guidelines to reduce environmental impacts from a life cycle perspective are available concerning the construction sector. However, basically all of them are modelled according to an attributional approach and there is a lack of studies that develop strategies for improvement based on a consequential LCA. The goal of this paper is to analyze to what extent the results differ when both models are applied on the same case, a representative dwelling located in Niel, Belgium. A conceptual optimization scenario for insulated exterior cladding has been added as well to examine to what extent different models affect the ranking of improvement strategies. For both approaches, the same foreground data and energy calculations are used, but the underlying structure of the models is different. The starting point is an attributional scenario, based on a Belgian guidance document 'Environmental profile of building elements' (EPBE) published by the Public Waste Agency of Flanders. The results of the entire life cycle indicate differences between the approaches, in direct relationship to the underlying modelling assumptions. The discrepancy becomes more pronounced when looking at the separate materials so the effect is not damped as a consequence of the aggregation in life cycle phases. Especially the three most contributing materials (steel, concrete and brick) show clear differences. The optimization scenarios underline previous statement, since the ranking of the different solutions is not equal according to both approaches. This research points out the emergence of a discrepancy between results when different modelling approaches are applied. The consequential model that complements the attributional EPBE study is therefore a useful addition to provide information for decision-makers. This way, the right information is available for all type of decisions.