Energy Renovation of Building Stock in Europe: The Role of Biobased Insulation Materials in the Transition toward Carbon Neutrality and Circular Economy.

Over the past thirty years, insulation materials have become a cornerstone of architectural design, shaped by evolving
energy regulations and thermal insulation standards . The 2018 revision of the European EPB regulations urged member states to intensify renovation efforts and achieve substantial improvements in building energy efficiency by 2050 . In Wallonia, as in all European regions, energy renovation represents a major challenge, given the heterogeneity of the residential building stock —both in rural and urban contexts and includes a high proportion of traditional pre-war buildings that are little or no insulated and highly energy-intensive. Consequently, demand for insulation materials is expected to increase significantly. It is therefore essential that this demand be aligned with
European and regional objectives for ecological and circular transition. In this context, this study investigates the advantages of biobased insulation materials from constructive, circular and environmental perspectives, with a specific focus on the energy renovation of the Walloon traditional residential building stock, built before 1920, before cavity wall systems were developed. Adopting a multidisciplinary and comparative
approach , it highlights the pivotal role of these "balanced materials" in the transition toward carbon neutrality and a circular economy.