Embodied energy and carbon of building insulating materials: A critical review

An extensive and updated review of 223 values about the embodied energy and carbon of building insulation materials, mainly retrieved from 156 Environmental Product Declarations, is proposed with attention to innovative and emerging insulation materials. Comparative analyses were carried out thanks to the adoption of the same functional unit (1 m² with a thermal resistance of 1m²K/W and a design life span of 50 years) to assess the consistence of reference values and the main sources of variability. The comparison suffers from many uncertainties and variance decomposition was employed to verify the main drivers of variability in the dataset elaborated. Data about traditional insulation materials show the lowest ranges of variation when reported per functional unit while the definition of reference values for innovative and unconventional insulation materials was quite difficult due to the low values found and their high variance. Traditional inorganic insulation materials exhibit competitive embodied impacts (glass wool: 16–31 MJ/FU and 0.6–1.2 kg CO₂eq/FU; stone wool: 21–66 MJ/FU and 1.4–4.2 kg CO₂eq/FU) if compared with fossil fuel derived (EPS: 44–78 MJ/FU and 1.9–3.5 kg CO₂eq/FU) or many emerging super-insulating solutions (aerogel: 251–372 MJ/FU and 11.6–18.7 kg CO₂eq/FU). Density is an important variability carrier for glass wool, stone wool, and EPS.