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Event Takeaways: What Will It Take? Designing Carbon-Free Buildings

Part of the What Will It Take leadership series

Recorded June 8, 2021

Click here to view the other panels from this series.

Print version of the content below available here.


  • Fernando Arias, Director of Sustainability, Clark Construction Group
  • Theresa Backhus, Associate Director, Building Innovation Hub
  • Arathi Gowda, Associate Director, Team Leader Performative Design Group, SOM
  • Melissa Wackerle, Senior Director, Sustainable Practice & Knowledge, The American Institute of Architects (AIA)
  • Anica Landreneau, Senior Principal, Global Director of Sustainable Design at HOK
  • Tommy Zakrzewski, Ph.D., Vice President, Director of Building Engineering Physics, HKS

The Hub and Clark Construction Group kicked off its series, “What Will It Take? The Path To 2050 And Carbon-Free Buildings,” with a panel focused on the role design and design professionals play in building sustainability, energy efficiency, and carbon emissions reduction. The robust discussion is worth watching in its entirety, but here are some of the key takeaways:

1.  Focusing on building performance gives us a tremendous opportunity to address multiple societal challenges simultaneously.

Landreneau emphasized that by investing in existing buildings, we can save an enormous amount of embodied carbon by using existing infrastructure investments, while also preserving historical and cultural heritage. Wackerle seconded this notion and argued that since many older buildings are blighted, there is an opportunity to engage community members and correct historic inequities while building stronger local economies. Finally, Zakrzewski highlighted the opportunities for smart buildings to integrate with the grid.

2.  The greenest materials are the ones we don’t use.

Landreneau and Wackerle pointed out that even the greenest building project uses additional embodied carbon, so the solution should be to reuse buildings and materials as much as possible. Landreneau emphasized that designers should first focus on designing intelligently, for example, supporting future reconfigurations to avoid later use of virgin materials. Wackerle discussed the need for a secondary market of building materials, which is so far nascent and localized, but could become more far-reaching and sophisticated.

3.  Human behavior will determine the success or failure of building decarbonization.

To fully decarbonize, both building occupants and the building industry need to shift behavior. The only way to do so is to change the way people think about their interactions with the built environment. Landreneau argued that we need to figure out how to design spaces that engage occupants in being efficient. People don’t understand how buildings relate to the environment or know how to read a building for efficiency or other measures. Similarly, Wackerle stressed the need for more practitioners to utilize simulation tools that demonstrate the value of passive building techniques and the ways buildings respond to nature. These simulations also need to factor in the human element into the design so that high-performing spaces genuinely feel better. “If a building is too hot or people are wearing sunglasses indoors, then that is a failure,” said Landreneau.

4.  Change is coming rapidly, and we need to be ready.

While sustainability professionals have been pushing for change for decades, the coming years are likely to produce a sea change in how companies and clients prioritize climate action. Gowda stressed the need to prepare for this opportunity by talking to clients now about what’s coming. Zakrzewski called for more cohesive higher education programs that enable graduates to execute immediately on low- and zero-carbon buildings and building materials.

5.  If we care about building decarbonization, we need to become activists for it.

Zakrzewski emphasized that we need to cultivate a carbon-reduction mindset by helping everyone understand how carbon plays into design decisions and talking about it at every opportunity. Gowda added that more organizations need to move from benchmarking toward advocating for more robust policies. In particular, Zakrzewski called out building performance policies as particularly powerful for incentivizing industry-wide shifts.

Bonus Q&A Content

  • Zakrzewski:

    I would say refrigerants are more operational carbon rather than embodied, but it does depend on what you put in on day one. The solution is to use more natural refrigerants, like ground-source heat pumps that use CO2.


    Project Drawdown listed refrigerants as the number one climate concern related to buildings. There’s an opportunity for innovation in mixing natural ventilation with mechanical ventilation. Increasing ventilation, as we’ve done during the pandemic, increases energy use.


    Natural ventilation is more resilient in cases of power outages, and constant indoor conditioning makes people uncomfortable. In a WWII hangar project I did, we used a deep-sea well to cool the air and help with humidification, and then used simulation to distribute the air.


    Changes are coming in requirements/code and we see more heat pumps. In addition, there are innovations like the use of use ammonia-based solutions in Europe or CO2 elsewhere.

  • Gowda:

    If you look all stages of embodied carbon, the ISO standard A1-A3 takes you to the gate of the manufacturer. We need to set up models designing for a circular economy, even though it doesn’t fully exist yet.


    We don’t have a good baseline for embodied carbon or EPDs, but we don’t need to let the perfect be the enemy of the good. Let’s start with what we do have because the clock is ticking.


    It’s all about data. The way that we do LCA is about 20 years behind how we do energy modeling. We need a huge acceleration to address that inflection point and how imperative the climate crisis is.


    We should not undervalue the impact and opportunity that the built environment has to solve a litany of problems with the same solutions. if we are thoughtful, then the built environment can be positive- improve health, carbon negative, improve resiliency

  • Wackerle:

    AIA adopted the COTE Top Ten awards as our new Framework for Design Excellence which has already led to the incorporation of new metrics for our Honors & Awards. Although there’s no threshold to meet (harkening back to Anica’s comment about the lack of embodied carbon benchmarks), we do request applicants to provide an embodied carbon calculation (in kgCO2e/m2/yr) for all AIA National Honors & Awards programs. Additionally, AIA added embodied carbon tracking to 2030 Commitment operational metrics in our Design Data Exchange (DDx) database.

  • Wackerle:

    Driven by the values of our members, AIA incorporated clear goals around climate action and racial equity in our 2021-2025 strategic plan. The stated goals are:

    • Climate action for human and ecological health
    • Advance racial, ethnic, and gender equity

    Strategic objectives from that plan inform our 2021 operations and programming. Every staff person at the institute is responsible for implementing both of those goals into their work. In addition, we track outcomes with a series of key performance indicators to measure success.

    For our members, the AIA 2030 Commitment Working Group recently published a new guide on Creating a sustainability action plan that works to help firms think through how their sustainability values and aspirations can translate into a comprehensive approach that transforms their company’s entire portfolio. The institute is also preparing a Climate Action Guide for architects to address the climate crisis through their own practices.

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