RMI modeled 40 US homes built with bio-based materials and found something worth sitting with: the houses stored more carbon than it took to build them.
RMI, the independent research institute formerly known as the Rocky Mountain Institute, published a study in April 2025 that asked a direct question. What happens if American homes are built from the biomass the country already produces and largely throws away? The findings are worth reading in full, and a few stand out.
A 107 percent reduction
RMI modeled 40 single-family homes twice: once with conventional materials and once with bio-based substitutes that meet the same structural and thermal requirements. Gross emissions fell only 6 percent. But once the carbon stored inside the materials was counted, net embodied carbon dropped 107 percent, from an average of 178 kg CO₂e per square meter to −2.5. The homes crossed from emitting to storing.
It outpaced the carbon removal industry by a wide margin
This is the figure that reframes the conversation. Under RMI’s most conservative adoption scenario, US homes could durably store roughly 100 million metric tons of carbon by 2050. That is more than 160 times all the carbon dioxide removal delivered by the entire CDR market to date. RMI notes plainly that the market and technological readiness of bio-based building products already exceed that of most engineered removal approaches. Technology is not waiting for a breakthrough. It is waiting for adoption.
And it does not cost more
Cost is the objection that ends most conversations about new building materials. RMI compared prices category by category and found at least one bio-based option at or near cost parity with the incumbent in every single assembly, from cavity insulation to structural sheathing to interior finishes. A home designed to maximize bio-based products could be built without raising its price.
Straw alone could build half a million homes a year
The US generates about 1.1 billion tons of underused biomass annually. RMI analyzed roughly 400 million tons of it and found that grain straw alone, at 41 million tons, could supply about half of all new home construction in the country today. Straw appears in more product categories in the study than any other feedstock: cavity insulation, board insulation, interior walls, and wall and ceiling panels. This is the material ECOR builds with, and it is currently burned or left to decompose.
The bottleneck is documentation
One detail deserves attention from anyone making these materials. To be included in RMI’s model at all, a product needed a third-party verified EPD. Many bio-based products that met every other criterion were excluded solely because they lacked one, which means the study’s already striking results are conservative by RMI’s own account. Among the actions RMI recommends to manufacturers, first on the list is producing an EPD as soon as production begins. We completed ours this year, and this is a good articulation of why it mattered.
What we take from it
The report describes a category rather than a company, and that is what makes it useful. It establishes that materials made from agricultural residuals can store carbon durably, meet code, compete on price, and support domestic manufacturing at a scale of 42,000 direct jobs and $79 billion in economic activity. The full report is freely available under a Creative Commons license, and we would encourage anyone specifying or building homes to read it.
Sources
Magwood, C., Bukauskas, A., Huynh, T., and Olgyay, V. Building with Biomass: A New American Harvest. RMI, April 2025. https://rmi.org/insight/building-with-biomass-a-new-american-harvest. Licensed CC BY-SA 4.0. All figures cited above are drawn from this report unless otherwise noted.
Rocky Mountain Institute analysis conducted using the Building Emissions Accounting for Materials (BEAM) life cycle assessment tool and the US Department of Energy Prototype Building Models, single-family detached base prototype.
EN 15804:2012+A2:2019. Sustainability of Construction Works — Environmental Product Declarations — Core Rules for the Product Category of Construction Products. European Committee for Standardization.
ISO 14025:2010. Environmental Labels and Declarations — Type III Environmental Declarations — Principles and Procedures. International Organization for Standardization.
Levasseur, A., Lesage, P., Margni, M., and Samson, R. “Biogenic Carbon and Temporary Storage Addressed with Dynamic Life Cycle Assessment.” Journal of Industrial Ecology 17, no. 1 (2013): 117–128.
Guest, G., Cherubini, F., and Strømman, A.H. “Global Warming Potential of Carbon Dioxide Emissions from Biomass Stored in the Anthroposphere and Used for Bioenergy at End of Life.” Journal of Industrial Ecology 17, no. 1 (2013): 20–30.
“Assessment of the Effects of Straw Burning Bans in China: Emissions, Air Quality, and Health Impacts.” Science of the Total Environment (2021).
“Bridging the Sustainability Divide: A Systematic Review of Environmental Product Declarations for Construction Materials (2015–2025).” Atlantis Press, 2025.
US Department of Agriculture and US Environmental Protection Agency feedstock and waste-stream data, as compiled in RMI’s Building with Biomass, Exhibit 16 and Appendix C.