ROI: Designing for reduced embodied carbon
The architecture profession can lead the way in going beyond operational carbon, the emissions associated with the energy used to operate the buildings, through addressing embodied carbon within their projects. Embodied carbon refers to the greenhouse gas emissions that are associated with materials and construction processes over the entire life cycle of a building.
Currently, the building industry generates almost 40% of annual CO2 emissions, illustrating that if significant reductions are taken, this industry can be a key leader in reaching decarbonization targets. Embodied carbon alone accounts for 11% of global annual emissions and is connected to issues of public health and equity. It is imperative that embodied carbon becomes a focus of emission reductions within the industry.
For more resources on embodied carbon, please see AIA's zero-carbon page.
Literature review completed by University of Washington’s Integrated Design Lab for AIA in 2022.
A building’s structure is one of the largest contributors to embodied carbon and capital cost; choosing efficient structural systems can significantly reduce both.1
Key efficient design talking points:
- A case study of an 18-story building showed that compared to a conventional reinforced concrete building, a reinforced concrete structure with a post-tensioned floor reduced embodied carbon and construction costs by 10% and 8%, respectively. The same study found that a completely mass timber building reduces embodied carbon by 26% and construction costs by 5%.1
- Mechanical systems have a significant impact on total embodied carbon over the lifespan of a building project.2 Incorporating passive design strategies reduces the size of mechanical system, decreasing embodied carbon and initial first cost, and also reduces operational expenses due to load reduction.3
- Efficient space planning reduces the area of a building and the necessary materials, which also reduces embodied carbon and upfront costs.4
- Minimizing earthwork and construction optimization strategies, such as minimizing idle truck and pump time and minimizing on-site transportation by optimizing the layout of construction site, can reduce costs and minimize embodied carbon of construction.5
- As building materials and systems become increasingly expensive in the future, designing for disassembly adds more value to buildings over time, as owners can salvage or sell building materials at the end of life, saving embodied carbon and providing a revenue stream.5,6
- One study of a precast concrete, 14-story building showed that designing for disassembly reduced deconstruction costs by up to 9.4% and reduced carbon emissions by up to 40% during the deconstruction process.6
- Robati, M., Oldfield, P., Nezhad, A., Carmichael, D., & Kuru, A. "Carbon value engineering: A framework for integrating embodied carbon and cost reduction strategies in building design." Building and Environment. 2021.
- Rodriguez, B., Huang, M., Lee, H., Simonen, K., & Ditto, J. "Mechanical, electrical, plumbing and tenant improvements over the building lifetime: Estimating material quantities and embodied carbon for climate change mitigation." Energy and Buildings. 2020.
- Hawkins, D., & Mumovic, D. "Evaluation of life cycle carbon impacts for higher education building redevelopment: A multiple case study approach." Energy and Buildings. 2017.
- Cousins, F., Broyles Yost, T., & Bender, G. "Think circular–Reducing embodied carbon through materials selection. MRS Energy & Sustainability." MRS Energy & Sustainability. 2018.
- Akbarnezhad, A., & Xiao, J. "Estimation and Minimization of Embodied Carbon of Buildings: A Review." Buildings. 2017.
- Akbarnezhad, A., Ong, K., & Chandra, L. "Economic and environmental assessment of deconstruction strategies using building information modeling." Automation in Construction. 2012.