News Brief

TallyCAT Links Revit with Product-Specific Carbon Data

Now in beta, the new tool facilitates embodied carbon decision-making through selection of specific products.

Finding ways to reduce embodied carbon during building design can take many forms, like building reuse, dematerialization, or alternative structural systems. But once design has advanced to a certain point, the main opportunities lie in finding preferred products within a given category, like lower-carbon concrete or gypsum board. The Tally Climate Action Tool (tallyCAT) helps identify such opportunities.

Currently in beta (version 0.50), tallyCAT is a free Revit plug-in. Despite its name, it’s a completely separate tool from Tally—recently renamed tallyLCA—which is whole-building life-cycle assessment software. Unlike tallyLCA, tallyCAT doesn’t account for the entire building life cycle, and it doesn’t include other environmental impacts like smog, eutrophication, or acidification. The focus is exclusively on up-front embodied carbon of materials.

TallyCAT works by linking a Revit model with the EC3 database of environmental product declarations (EPDs). Designers can play around with different EPD options and watch things change instantly within the model, helping them “map primary impacts, with relatively little effort, in a visual way,” according to Jesce Walz, architectural designer with Perkins&Will, which is co-developing the tool with C Change Labs with the support of Building Transparency and funding from the province of British Columbia.

The goal is to connect designers to embodied carbon data in a way that fits into normal workflows, explained Elton Gjata, a digital practice manager at Perkins&Will. “There is this fantastic database of EPDs, but it’s so inaccessible to designers,” Gjata said. Not that long ago, he added, the level of analysis available in seconds through tallyCAT would have taken a week of research.

There is a catch: designers have to use Revit responsibly. “In real projects, sometimes designers label everything ‘generic concrete #3,’” said Gjata. “There is a bit of a mental shift in the way we need to use BIM [building information modeling] going forward. In the past, it was just a way to get drawings faster. We want the ‘I’ in BIM.”

The team hopes the instant feedback will not only help designers but also incentivize manufacturers to provide more EPDs—and hopefully to reduce the embodied carbon of their products.

Walz describes v0.50 as a “very beta release,” joking that the team has been calling it “tallykitten.”

“We want to open it to the community and get feedback,” explained Gjata. Users will be able to offer comments on this version through March 2023 by using the purple “feedback” button in the software.

It’s unclear whether tallyLCA and tallyCAT will remain separate tools in the future, with Walz saying tallyCAT could become a whole-building life-cycle assessment tool “over time” while also conceding that its approach “is different from the way LCA data currently works, so there may be some industry alignment work to do.”

More on embodied carbon tools

Tally LCA Software to Include Product-Specific Data

Raze or Retrofit? CARE Tool Has the Answer

Free Tool Estimates Embodied and Operational Carbon

A New Embodied Carbon Calculation Tool for Passive House

Embodied Carbon Tools: Assessing the Options

For more information:

Building Transparency

Published January 9, 2023

Melton, P. (2022, December 21). TallyCAT Links Revit with Product-Specific Carbon Data. Retrieved from

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