Resource efficiency for closed-loop circularity of building insulation materials in Europe

Insulation materials play a central role in improving the energy performance of Europe's largely inefficient building stock, of which about 75% still requires renovation. As demand for insulation increases, the sector faces growing pressure to reduce dependence on primary raw materials. In this study, we develop the first comprehensive sector-wide static Material Flow Analysis (MFA) for the year 2016 covering the five major insulation materials used in Europe such as glass wool, stone wool, expanded polystyrene (EPS), extruded polystyrene (XPS), and polyurethane/polyisocyanurate (PUR/PIR) across the EU-28. Results show that insulation production in 2016 required approximately 6.4 million tonnes of material resources, of which about 78% were primary materials derived from natural sources. A closed-loop recycling scenario was then evaluated in which all available pre-consumer waste (PCW) is reintegrated into insulation manufacturing. Under this scenario, total material throughput in the system increased slightly (by 1.8%) due to greater circulation of secondary materials, while demand for primary materials decreased by 9.7%. Sensitivity analysis indicates that the improvement in primary-material efficiency (RE_PM = 9.7%) is robust (±3.1 percentage points), with model results most sensitive to mineral-wool substitution parameters and PCW availability. This study evaluates material flows on a mass basis only; environmental impacts, energy use, and upstream emissions are not assessed. Therefore, reductions in primary-material demand should not be interpreted directly as environmental benefits. The results provide a quantitative baseline for circular material management in the European insulation sector and highlight the need for complementary environmental assessments to guide sustainable decision-making.