Climate mitigation potential of biobased insulation materials: A comprehensive review and categorization

Insulation materials in the construction industry play a crucial role in improving the thermal performance of buildings, reducing energy demands, and reducing carbon emissions. With the growing emphasis on decarbonization, the construction sector is increasingly adopting bio-based insulation materials from renewable and eco-friendly sources as a more sustainable circular economy (CE) strategy to replace mineral and plastic insulation materials. However, due to limited environmental data availability, their efficacy and environmental sustainability in climate mitigation relative to their conventional counterparts remain unclear. This study fills this critical knowledge gap by conducting a literature review and mapping the key physical and environmental properties of bio-based insulation materials, thereby assessing their potential for climate mitigation. Specific definitions and criteria established in this study for biobased insulation materials facilitated the mapping of 174 emerging materials and products at the lab-scale. These include 39 distinct bio-based materials, either in their raw form or combined with 40 binders from various material groups such as minerals, polymers, biopolymers, and other innovative solutions. Most mapped products show favorable performance in cradle-to-gate embodied carbon (EC), benefiting from biomaterials' carbon storage. However, significant variations in physical and environmental properties among these products highlight areas for improvement, particularly in embodied energy (EE) and thermal conductivity compared to glass wool. This paper attempts, for the first time, a comprehensive categorization of these products based on three criteria: thermal performance, climate mitigation, and environmental sustainability, grounded in critical physical and environmental properties. Cellulose and straw bale emerge as competitive options for thermal performance and environmental sustainability in climate mitigation, with potential for scalable adoption. However, further research on the physical and environmental properties of bio-based insulation materials is crucial to improve their assessment and categorization, and consequent recommendation for broader adoption in sustainable construction practices.