Cradle-to-Gate Embodied Carbon of Building Facade and Enclosure Systems: A Systematic Review

Published life cycle assessment (LCA) results for building facades and enclosures are difficult to compare because of differences in system scope, methods, and reporting. This systematic review synthesizes cradle-to-gate embodied carbon results by system type and assesses their comparability. Following PRISMA 2020, searches of five databases, supplementary searches, and citation tracking (2010 to January 2026) identified 146 studies with 800 options in 13 system types. The primary dataset contained 597 options with strict A1–A3 results per square meter of facade or enclosure. Their median global warming potential (GWP) ranged from 9.1 kg CO2e/m2 for insulation components to 207 kg CO2e/m2 for building-integrated photovoltaic (BIPV) modules. Opaque walls, the largest category (231 options, 52 studies), had a median of 48 kg CO2e/m2. Using one value per study changed medians by less than 4 kg CO2e/m2 in the four largest categories and up to 72 kg CO2e/m2 in smaller ones. Therefore, small-category results are descriptive only. Comparison was limited because one-quarter of options were not reported per facade area or the reporting included stages beyond A1–A3. In addition, for 48% of options containing bio-based materials, studies did not state whether stored carbon was credited. In studies that reported both versions, the credit alone turned 15 of 26 results negative. Values should therefore be compared only within a category and at equivalent performance, boundary, and biogenic carbon treatment. To address these gaps, this review proposes a minimum reporting checklist for consistent and comparable facade LCA results.