By now it is routine for project teams to consider energy efficiency as part of the design process. But there is growing awareness that averting the worst effects of climate change will require more than reducing the amount of fossil fuels it takes to operate buildings. Embodied carbon—the greenhouse gas emissions associated with material production and construction—will also have to be reined in. “If you look at a typical building constructed today, between now and 2050, 50 percent or more of its emissions will be embodied carbon,” says Kate Simonen, director of the Carbon Leadership Forum (CLF) at the University of Washington.

Earlier this week, at the 2019 Greenbuild conference being held in Atlanta, Simonen’s organization officially launched the beta version of the Embodied Carbon in Construction Calculator, or EC3—free and open-source software intended to help designers, engineers, and clients assess and reduce these upfront emissions. Unlike existing embodied carbon tools, EC3 is focused on the specification and procurement phases of projects, allowing the comparison of similar materials from different suppliers. 

Stacy Smedley, director of sustainability for Skanska USA, and Phil Northcott, CEO of software developer C Change Labs, came up with the idea for the tool 16 months ago, with initial development funded by Skanska and Microsoft. CLF served as incubator with financial support from Autodesk, Interface, the MKA Foundation, and the Charles Pankow Foundation. But more than 30 other partners, including architecture firms, engineering companies, building owners, and industry associations, contributed or collaborated on the tool.

According to Smedley, EC3 was born out of frustration. Previously, assessing the embodied carbon of a single material was cumbersome and time-consuming, involving the evaluation of environmental product declarations (EPDs). These third-party verified documents, which disclose information about the life-cycle and environmental impacts of products, can run up to 17 pages. “If it takes four hours to evaluate one product, think about multiplying that by all the materials in a building,” she says.

EPDs are at the heart of the new tool, but comprise a digitized and searchable database. EC3 currently includes EPDs for concrete, steel, wood, aluminum, building enclosure products, and carpet, with more categories to be added. It connects to BIM 360, Autodesk’s cloud-based construction management platform. In a few clicks, users can choose desired performance criteria, such the compressive strength of a concrete mix, as well as global warming potential, and can see their selections mapped in a 3D view.

Some industry experts worry that EPDs, which lack standardization, are difficult to compare. They point out that many are based on industry averages, rather than on a particular product from a specific supplier, and that many manufacturers have not published EPDs for their products. To deal with these problems and the associated uncertainty, EC3 relies on a methodology that assigns an embodied carbon range to products, rather than an exact number.

Smedley acknowledges that the data isn’t comprehensive, but says that the embodied carbon problem is urgent. “We don’t have time to wait for perfection,” she says. It seems that many in the industry agree. Already more than 1,500 potential users have registered at to try EC3.