The cost of sustainability in the construction sector – the case of family houses in Belgium

The housing sector is a major contributor to greenhouse gas emissions and a large body of literature has focused on measuring the environmental impact of houses, using the Life Cycle Assessment (LCA) methodology. This literature reaches the conclusion that alternative construction materials should be used to reduce the environmental impact of buildings. While such research provides essential knowledge on the carbon footprint of the housing sector, few studies take into account the economic side of the issue. This paper addresses this gap by calculating the Life Cycle Cost (LCC) of houses and matching the results with the LCA stages. The methodology is developed for two reference houses in Belgium. Considering all elements and materials used in the construction process, this approach allows a comparison of each house’s elements based on the required investment to abate their carbon footprint. The most striking results are that (1) the operational stage (i.e., the use of houses) accounts for about 65% of the total carbon impact of a house; (2) a 1€ investment in sustainable materials induces a drop of 1 to 1.3 kgCO₂eq; (3) this effect is heterogeneous across materials, with the highest returns obtained for external walls (-6 KgCO₂eq) and windows (-3 to -6 kgCO₂eq) and the lowest returns obtained for ground floor (-0.3 kgCO₂eq).