Life cycle assessment (LCA) of thermal insulation materials: A critical review

Thermal insulation of buildings is a key factor in reducing the environmental impact of the building sector by lowering the energy demand of buildings for heating and cooling. The choice of material for the thermal insulation has become more important with the rising need for sustainability. Life cycle assessment (LCA) is a common tool to assess the environmental impact of products or services. This study reviews the available literature on LCA of building thermal insulation materials in a structured literature review. The aim was to provide an overview over the literature, critically assess the methodology used as well as the results of the LCAs, especially to identify the potential of renewable based thermal insulation. This review covered 47 studies on building thermal insulation materials in total and developed a pedigree matrix to assess the quality of the articles. The results show at times significant methodological issues and a lack of transparency on the implementation of methods within the LCA framework. For the comparative LCA results, the review suggests that among the market leading materials, EPS, Stone wool, and Glass wool are highly similar in their impact. Other materials such as XPS or PUR show overall higher impacts in the majority of categories. The results further suggest that renewable based materials tend to have a lower environmental impact, but are not necessarily better. The main cause of impact for non-renewable organic materials is the raw material and for inorganic materials the production process, while the most common main driver of impacts for renewable based materials are binders and additives. This highlights further potential for improvement for the environmental impact of renewable based thermal insulation materials by lowering the need for additives.