Embodied carbon benchmarks of single-family residential buildings in the United States

Abstract

The objective of this work was to define and implement a methodology for establishing theoretical, science-based embodied carbon benchmarks for single-family, detached residential buildings based on the United States Department of Energy prototype single-family residential building energy models. The expected differences in materiality across 16 climate zones and 4 foundation types resulted in 64 archetypical single-family residential building models. Probabilistic life cycle assessment was applied to a material quantity takeoff of each building model to approximate each building model's material use intensity (MUI, kg/m²) and embodied carbon intensity (ECI, kgCO₂e/m²). The results indicate that average MUIs range from 185 to 346 kg/m² and average ECIs ranged from 39 to 121 kgCO₂e/m². The choice of life cycle assessment (LCA) data had a significant impact on the ECI results. More specifically, ECIs calculated using One Click LCA were approximately 7 % and 44 % higher than those from Tally and Athena Impact Estimator for Buildings (Athena), respectively. When accounting for theoretical maximum biogenic CO₂ storage (not including end-of-life treatment), all net CO₂ emissions intensities computed using Athena were negative, indicating that the buildings were net-CO₂ storing. When using One Click or Tally, 28 % and 50 % of the building models were net-CO₂ storing, respectively. The results presented herein can be used to establish theoretical, science-based embodied carbon benchmarks for single-family residential buildings in the United States. In addition, the methodology could be adopted by entities seeking to establish building-related embodied carbon emissions reduction targets.