Clark Nexsen’s Don Kranbuehl, FAIA, LEED AP, recently attended the AIA Large Firm Roundtable Summit on Carbon and left with a strong sense that building design must change in a major way. The built environment is responsible for nearly 40% of global CO2 emissions, giving architects, engineers, and building owners a unique chance to reduce human impact on the planet. Using building carbon analysis, design teams can make informed decisions to reduce both operational and embodied carbon, helping slow climate change while creating healthier, more sustainable spaces.
Why Reducing Carbon Matters
Global carbon emissions have been rising sharply over the last 150 to 200 years. Scientists warn that we have roughly a decade to make significant changes, such as reducing the carbon footprint of buildings, to bring emissions under control. This is why sustainability goals in the architecture, engineering, and construction (AEC) industry often focus on the year 2030. A key area of concern is embodied carbon, the carbon released during material production, transportation, and construction.
The Paris Agreement outlined three major climate goals:
- Reach peak CO2 by 2020
- Reduce carbon emissions by 50% by 2030
- Achieve zero emissions by 2050
Exceeding a 1.5-degree Celsius increase in average global temperature could have devastating consequences. The following projections show how temperatures may rise depending on the actions we take:
“Business as usual” scenarios predict an increase of over 8 degrees Celsius by 2200, while reducing emissions can help prevent catastrophic warming.
The opportunity to change this trajectory is urgent. By 2060, global building stock is expected to double, with nearly 40% of this growth occurring in the next 15 years. Reducing both embodied and operational carbon in these new and renovated buildings is critical to meeting sustainability goals. While operational carbon—emissions from energy use during a building’s life—grows over time, embodied carbon impacts are immediate and often much larger. In fact, only 28% of total building emissions in the next decade will come from operations, making early design decisions crucial.
Tools for Reducing Carbon in Buildings
Designers now have access to a variety of tools that make building carbon analysis more precise and manageable. These tools help teams compare materials, analyze structural systems, and track carbon impacts throughout the design and construction process. Each tool serves a specific purpose depending on project type, stage, and location.
Tally
Tally is a Revit plug-in developed by Kieran Timberlake. It is especially useful in the early design phases for comparing materials and performing total building analysis. Tally is often paired with energy modeling to support early decision-making.
Beacon
Beacon, a free Revit plug-in by Thornton Tomasetti, focuses primarily on structural systems and helps designers understand the carbon impact of different structural choices.
Athena
Athena is a standalone analysis tool that is particularly useful for transportation projects. It integrates a large database of material information to help assess the overall carbon footprint of a building.
EC3
The Embodied Carbon in Construction Calculator (EC3) is a free tool by the Building Transparency Group. EC3 is most effective during the construction documents phase and construction administration, helping optimize material selection and reduce carbon impact.
Environmental Product Declarations (EPDs)
EPDs provide verified data on materials’ environmental impact. They are often used as inputs for Tally, Athena, or EC3 and help ensure that the materials specified align with sustainability goals.
Simple Strategies to Reduce Carbon
While software and regulations help, practical, common-sense approaches still provide the greatest opportunities to lower carbon emissions. The AIA suggests several straightforward strategies:
- Reuse existing structures whenever possible
- Limit materials that produce high carbon emissions
- Choose lower carbon alternatives or materials that store carbon
- Use high-recycled content materials
- Maximize structural efficiency
- Reduce unnecessary finish materials
- Minimize construction waste
The structural system of a building—mainly concrete and steel—has the largest impact on carbon emissions. Adaptive reuse and renovation of existing buildings can result in significant savings. Working closely with structural engineers to optimize materials is essential for low-carbon outcomes.
Case Studies: Using Carbon-Reducing Tools in Practice
UVA Wise – Wyllie Hall Adaptive Reuse
At the University of Virginia’s Wise campus, Clark Nexsen renovated Wyllie Hall, a 22,500-square-foot concrete building built in 1966 with a 1996 addition. The project transforms the building into a modern College of Nursing facility with labs, lecture halls, shared spaces, and faculty offices.
Building carbon analysis using Tally and EC3 demonstrated the importance of reusing the existing structure. Reinforced concrete, a major contributor to embodied carbon, was retained to avoid additional emissions. By reusing the building, the design team estimated a carbon savings of around 700 metric tons.
Additional design features, like a skylight in the existing roofline, added slight carbon impacts but improved daylight and student well-being. Wood was used extensively inside, providing warmth while sequestering carbon.
Alamance Community College – Biotechnology Center of Excellence
The new Biotechnology Center at Alamance Community College is a 33,000-square-foot lab building with a steel structure, composite deck, and reinforced concrete foundation. Laboratory design requires high vibration thresholds, making steel and concrete essential.
Here, building carbon analysis helped identify ways to minimize concrete and steel usage while meeting program needs. Tally was used to assess carbon by line item, helping the design team prioritize actions. EC3 highlighted further opportunities for reduction, such as optimizing material choices to lower the overall carbon footprint.
Making Carbon Reduction a Standard Part of Design
Reaching zero emissions by 2050 requires that carbon reduction become a natural part of every design process. Using tools like Tally, Beacon, Athena, and EC3, and combining them with practical strategies, allows architects and engineers to identify opportunities to reduce embodied and operational carbon at every stage. Small, informed decisions add up, helping the AEC industry create sustainable buildings that are better for both people and the planet.
