New Free Tool Calculates Carbon Footprints of Buildings

Designed for low-rise buildings, it's an effective tool to drive down embodied carbon.

A house under construction with scaffolding around it.
United Kingdom house builders could use the BEAM tool and get rid of brick.

Travelpix / Getty Images

Calculating the carbon footprint of buildings can be tricky but a newly released tool aims to make it easier. The free tool, called BEAM (Building Emissions Accounting for Materials) Estimator, is a product of Builders for Climate Action and answers the questions: "What is the carbon footprint of my building materials? And how can I reduce those impacts?"

The Canadian group is "working with builders, designers, developers, policy-makers, researchers and manufacturers to tackle the serious impact of buildings on our climate and work toward real zero carbon buildings." At its helm is Chris Magwood, director of research at Builders for Climate Action and a Treehugger regular.

Here at Treehugger, we have long discussed the importance of carbon emissions rather than energy efficiency, which everyone has worried about for 50 years. In particular, we have stressed the importance of embodied carbon—an unseen area of the building industry.

What Is Embodied Carbon?

Embodied carbon emissions, often shortened to embodied carbon, are the total of the emissions from the making, maintaining, and end of life of materials embodied in buildings or products, as distinct from operating energy and carbon emissions.

Much of our inspiration came from Magwood, who for years was a voice in the wilderness.

Chris Magwood at the Green Building Show
Chris Magwood at the Green Building Show.

Lloyd Alter

Before BEAM launched, Magwood noted on LinkedIn, "It's hard to believe that a tool that began its life to help me with a master's research project is about to be released publicly tomorrow!" That's him in the photo above talking about his thesis back in 2019.

"As the LinkedIn line indicates, BEAM started with my master's thesis, which was to explore the upfront emissions from low- and mid-rise residential construction and then to compare the upfront results to operational emissions," Magwood told Treehugger. "My first strategy was to use an existing LCA (life cycle analysis) tool. But after trying them all, I found that none of them were going to meet the requirements I'd set out when deciding on a tool. They all fell short in different but important ways."

Magwood told Treehugger the shortcomings included:

  • Lack of residential material/assembly options (the tools are geared more toward large buildings)
  • Lack of consistent data (each was a mix of EPDs [Environmental Product Declarations], external LCA studies, and/or internally conducted LCA studies)
  • Lack of consistent approach to carbon storage methodology
  • Lack of "alternative" materials

"After trying a bunch of workarounds, I discussed with my supervisor the idea of building my own EPD database and using that raw data to inform the studies," said Magwood. "At that time, the EC3 tool hadn't quite launched—and after it did it lacked many important material categories for the study—so I went ahead and combed the web for as many EPDs as I could find and built the EPD data into a crude spreadsheet in which I could input takeoff quantities from the plans I was studying to build out my results."

Magwood added: "After running my first model home through the spreadsheet, it was clear that it was giving me good results, but that it had been built to suit just one model. So I added the flexibility to input the building dimensions as a separate function so that my material calculation formulas could now respond to any given dimension."

And voilà—a tool was born. After more work and requests for it, Magwood said they "decided to name it and work toward releasing it publicly."

As architects and designers learned about embodied carbon, they found it was hard to measure. The information just hasn't been easy to find or was not in one place. Or, like the EC3 tool, it was designed for bigger projects and was more difficult to use.

The BEAM estimator makes it relatively easy. Architect Michael Klement, who beta-tested the tool, noted:

"Once we were enlightened to the fact that we had been barking up the wrong tree all along—that our real focus should be on carbon not merely energy—we found ourselves lost in the woods. We knew what our focus should be, but we needed a tool to help us metric the actual planetary impact of our projects. Enter the BEAM tool. Clear, easy to use (even for an architect), and effective. This tool is a game changer."
Carbon emissions

World Green Building Council

As the concept of embodied carbon has evolved, it has been broken down into different stages. So where I once wrote that we should call all embodied carbon "upfront carbon," that term is now generally applied to the Product Stages, A1-A3, and the Construction Process Stage, A4-A5.

Builders for Climate Action use a new term, material carbon emissions (MCE), which are a subset of upfront carbon, just the product stage including raw material supply, transport to factory, and manufacturing. Magwood previously explained to Treehugger the construction process footprints were "much less significant than might be expected (3% to 6% of total emissions), and it's impossible to estimate them accurately." This is a good point, given the distance materials travel to sites and the way people put them together could vary wildly.

On the BEAM site, it is explained in greater detail, "Product emissions are today emissions... they are committed to the atmosphere before the building is built. Since we need to reduce emissions now, these are the emissions that are happening now." (I have been using the term "now emissions" but "today emissions" is better.)

They also note that "the widest pool of data exists for A1-A3 Environmental Product Declarations" adding: "It requires too many assumptions to accurately build A4-A5, B and C life cycle stages into a tool. We explored options for counting these life cycle stages in BEAM, and could only see flawed and inaccurate ways to do so."

Sneak Peek

Builders for Climate Action

The BEAM estimator does appear relatively easy to use. Given Magwood's background in alternative materials like straw bale, it is pretty thorough for those who are really interested in driving down their carbon footprint with natural products.

sneak peak at material options

Builders for Climate Action

BEAM is designed for smaller buildings and most of these will be likely made of wood, which has probably the lowest upfront carbon of any structural material. Significantly, while it does count carbon storage for some materials like straw—or those sourced from forestry residues and recycling streams—it does not attribute carbon storage to virgin timber products.

Sneak peek totals

Builders for Climate Action

"There remain important and unresolved concerns with current accounting methods related
to virgin forest products like lumber. Some of these concerns include uncertainty about the amount of carbon released from soils during logging operations; the amount of carbon returning to the atmosphere from roots, slash and mill waste; the amount of carbon storage capacity lost when a growing tree is harvested; and the lag time for newly planted trees to begin absorbing significant amounts of atmospheric carbon dioxide. These factors and others are being researched and deliberated by experts from academia, the forestry industry, the building industry, environmental advocacy organizations, and LCA professions."

As we noted in an earlier post where they were counting the carbon storage of the mass timber, it's complicated, so the BEAM estimator leaves them out because the issues are unresolved. The calculator also doesn't include big items with big footprints, like mechanical, electrical, or plumbing (MEP) materials, due to a lack of good data.

But this is all a new and evolving science, and this will come. As they conclude on the BEAM site, "There is a great deal of work happening in the LCA world, and we will continue to participate in these discussions and bring developments and changes to BEAM as they evolve."

I have written many times that when you look at the world through the lens of upfront carbon, it changes everything. But it is hard; there is so little information and so few tools. At least with buildings, this is changing. As energy expert and self-described building geek Marc Rosenbaum said while describing the BEAM estimator:

"This is the tool that those passionate about great environmental residential construction have been waiting for. Being able to evaluate the embodied carbon performance of our buildings will take its rightful place alongside of their operational performance."

There are no excuses for ignoring the issue any longer. Get your own BEAM estimator from Builders for Climate Action, in metric or American measurements.

View Article Sources
  1. "BEAM: What's the carbon footprint of your building?" Builders for Climate Action.

  2. "Introducing the BEAM Estimator." Builders For Climate Action.