Owings and Merrill

Rebecca Delaney

It is difficult to have major countries arrive at one accord on any topic. However, in 2015, nearly the entire world agreed to reduce the escalation of carbon dioxide in the atmosphere to curb the effects of climate change. In fact, reducing carbon is the crux of the Paris Agreement, the Sierra Club’s #Readyfor100 campaign, as well as the net-zero building codes, policies, and energy ordinances being adopted across the world.  Under the Biden administration, the United States has committed to a 50-52 percent reduction in U.S.-emitted greenhouse gas pollution from 2005 levels by 2030; a carbon emission-free power sector by 2035, and net-zero emissions economy-wide by no later than 2050.  The U.S. General Services Administration has declared reducing embodied carbon is their next design imperative.  And as policymakers, designers, scientists, and stakeholders around the world continue to formulate the best strategies for addressing climate change, the need to develop holistic and long-term solutions that balance many complex criteria has become more apparent.

The industry has spent the last several decades focused on reducing energy and progressing policy to deliver better-performing buildings. The world is converging on EN 15978 for a standardized ‘Whole Life Carbon’ Life Cycle Assessment (LCA) definition and methodology, which accounts for both operational and embodied carbon. This accounts not only for operational carbon (B6) but also raw materials/manufacturing/transportation(A1-A3), construction (A4-A5), maintenance (B1-B6), and end-of-life (C1-C4) carbon. 

It is no longer sufficient to only reduce energy; every project must create a roadmap to net zero. We must avoid on-site combustion of fossil fuels for heating, instead designing for all-electric buildings ready to leverage a clean electric grid. We must account for the embodied carbon of all the materials and equipment we specify. We must consider building and system reuse whenever possible and account for associated costs and the potential limitations of existing grids.

Current data is already providing a helpful framework for future innovation. We know the most common refrigerants have high embodied carbon, yet some of the most energy-efficient systems use a significant amount of refrigerant. Therefore, the transition to refrigerants with low global warming potential must accelerate, and we must find ways to reduce system leakage. We know the use of on-site renewables is critical for a net-zero roadmap, however current photovoltaic panels have high embodied carbon6. The whole life carbon LCA can better inform the net gain for each of these design considerations.

Despite these advances, there is a glaring lack of information regarding the embodied carbon of HVAC systems, which we believe accounts for up to 15-49 percent of the embodied carbon in buildings based on a recent CIBSE study. This information is provided by manufacturers in environmental product declarations (EPDs), but there are limited EPDs available for building systems. 

As operational carbon is reduced, the percentage of carbon emissions associated with embodied carbon will increase. We must partner with organizations like the Green Building Advisory Council and the Carbon Leadership Forum, who are bringing together industry voices to advocate for more comprehensive and transparent product data and advances in policy regulations as they pertain to HVAC systems to achieve our global goal of successfully curbing climate change.