A look at residential building stock in the United States-mapping life cycle embodied carbon emissions and other environmental impact

In the United States, the largest knowledge gap concerning embodied carbon in buildings exists at the whole building level, due to a lack of building-level data at the national level and a lack of methodology. To fill this knowledge gap, the main goals of this study are (a) to propose and test a methodology that maps the life cycle embodied carbon (LCEC) and other life cycle environmental impact (LCEI) from both operational and embodied carbon at the whole building stock level and (b) to assess the LCEC and LCEI of the US residential building stock using the proposed methodology. A four-step bottom-up approach was used to assess the embodied carbon and environmental impact of the US residential building stock. Four building segment types and 64 housing archetypes were generated for this study, which represent over 95% of the US residential building stock. Four additional LCEI indicators are measured beside LCEC: ozone depletion potential, eutrophication potential, smog formation potential, and acidification potential. Among the four building segments, the findings indicate that single-family detached houses and large multifamily houses are the top contributors to embodied carbon in the United States, contributing 20% and 80%, respectively. Furthermore, the large multifamily house is the most embodied carbon-intense building segment type (an average 144 kg CO2eq/m2/yr) and is the leading building segment contributing to all environmental impact categories except acidification: 100% to ozone depletion potential, 85% to eutrophication potential, and 78% to smog formation potential. This is mainly related to the construction types and building materials used in large multifamily houses. California, New York, Texas, Florida, and Illinois are the five main contributors to the five environmental impact categories measured in this study and account for around 44% of the LCEI from the US residential building stock.

Automated summary

In the United States, there is a significant knowledge gap regarding embodied carbon in buildings at the whole building level. This study proposes and tests a methodology to assess the life cycle embodied carbon and environmental impacts of the US residential building stock. The findings highlight the contribution of single-family detached houses and large multifamily houses to embodied carbon, with the latter being the most carbon-intensive building segment.