Life cycle assessment and circularity of bio-based insulation materials: An overview for the construction sector

The growing interest in low-energy and sustainable architecture has driven a demand for buildings with minimized environmental footprints. Within this context, building insulation materials serve as key players in curbing operational energy usage within the construction sector. However, their production and use have been identified as significant contributors to carbon emissions and overall environmental impacts. Notably, the embodied carbon in insulation products varies significantly, ranging from materials derived from plastics (e.g., EPS, XPS) or mineral fibers (e.g., glass wool, rockwool) to those based on biological components. Remarkably, the latter often exhibit a carbon-negative balance, presenting a promising solution in the quest for sustainable construction materials. Despite this inherent advantage, the global utilization of bio-based insulating materials still hovers below 10%. Wood fiber materials account for nearly 60% of this usage, followed by cellulose fibers constituting approximately 30%, leaving the remaining 10% to encompass all other bio-based insulation products. This chapter aims to provide a comprehensive analysis of the characteristics of both traditional and innovative bio-based insulation materials to understand: (i) how bio-based insulation materials behave in terms of circularity and sustainability; (ii) what CE–LCA considerations are essential for material selection; and (iii) how to make a trade-off between circularity, LCA and physical properties (energy use, insulation, acoustics).