What the White House's new National Definition of a Zero Emissions Building means for architects

As most architects know, building emissions make up about 40% of total global carbon, according to the United Nations. As the planet warms, it’s essential that the building and construction sectors reverse this trend. 

During the opening keynote of AIA’s 2024 Conference on Architecture & Design in Washington, D.C., in June, White House Climate Advisor Ali Zaidi announced that the White House, in partnership with the Department of Energy, had released a National Definition of a Zero Emissions Building to aid in the effort of reducing carbon emissions from the building sector. According to the definition, a zero emissions building is highly energy efficient, doesn't emit greenhouse gases directly from energy use, and is powered solely by clean energy.  

The national definition applies to both new construction and existing buildings and aims to serve as a framework for the industry. By using these guidelines, architects and other members of the AEC industry can achieve measurable reductions in the operating emissions of buildings. The definition is designed to drive investment into zero emissions buildings and send a market signal to prioritize the elimination of emissions from buildings. It currently focuses on operational carbon and building energy efficiency. 

It was a rigorous six-month process to arrive at the first version of this definition, with work continuing immediately to address additional aspects of the built environment around embodied carbon and the emissions related to the extraction, manufacturing, and life of a material. DOE plans to incorporate public comments later this year.  

The definition itself was developed not as a national standard or new rating system, but instead to help align public and private entities in how they approach and talk about zero emissions. All parties also hope to see adoption and application of this definition to spur market transformation across the building industry.  

How will this new definition affect the way we design? What should we tell our clients? 

First, optimize: The new standards will push architects to optimize building designs first before offsetting energy use with clean energy. 

New buildings will be required to demonstrate an Energy Star score of 90 or greater, or for buildings that do not qualify for the rating, to be 10% more efficient than the most recent model code. Note that the definition references the ‘most recently published model code,’ which currently is IECC 2021 and will soon be IECC 2024. This may be more stringent than what your local code has adopted. This will encourage AHJs to look at adopting newer codes as they are published and push project teams to design to newer standards.  

Second, electrify: Buildings must be free of onsite greenhouse gas emissions for energy use. This is written explicitly to address onsite operations and exclude emissions from materials or refrigerants until future updates to the definition. This does, however, encompass all building operations including heating, cooking, and process loads. The only exception is for emergency backup generators. Hospitals and laboratory buildings may find this criterion particularly challenging. 

Third, offset: All building energy use must be offset by clean energy. The offsets may be a combination of onsite or off-site energy that meets one of the four referenced programs. The idea is that buildings select the path that makes sense for them and then meet the criteria of that path. Not all the paths handle off-site renewables or additionality the same, so be sure to study each path as it may apply to your project.

District energy beware: Buildings powered by district energy have additional criteria to ensure that the district energy plant itself is operated entirely by clean energy and without onsite combustion. This may be a challenge for campuses with existing district plants. However, as plant equipment nears the end of its useful life, the hope is that this definition will push owners to consider electrification and clean energy. 

Finally, track: Compliance is not a one-time event. It will require continuous tracking through the DOE’s Energy Star Portfolio Manager. After the building has been in operation for one 1 year, the existing building efficiency criteria will apply to maintain an Energy Star Score greater than 75 or demonstrate that the building is 35% more efficient than the median peer facility.  

Tools and resources: Talk to clients about recording all existing assets in Portfolio Manager with no less than 12 months of utility data. For new projects, utilize Target Finder to establish the current benchmark or enter data in the AIA 2030 DDx. The DDx can help a project track efficiency across design. While the program uses CBECS 2003 as the baseline, any project achieving greater than 60% savings is well on its way to meeting the efficiency requirements for new buildings. (IECC 2021 is approximately 50% better than CBECS 2003 + the 10% additional reduction for the definition = 60% minimum reduction to be on track to meet the zero emission building criteria.) In addition, report energy use by fuel source in the DDx to help track compliance for no onsite combustion as well as renewable offsets needed to comply. 

The opportunity: A significant portion of our existing building stock and the associated systems are reaching the end of their useful life. Benchmarking the building operations now can help clients see where they stand related to this definition and where they could go with our help. 

AIA Committee on the Environment (COTE®) leadership additionally notes, “The definition also creates minimum criteria for public and private entities to adopt to ensure that it is handled uniformly across the country. This definition is for all building types, both commercial and residential. This will require different methods of implementation by different firm scales and project types, and AIA will work with our members on how to best support the needs of firms of all sizes to meet these goals.” 

What's next? 

AIA also commends the administration for adding the forthcoming Part 2 of the definition on embodied emissions, which AIA and its members are working with officials to advise, and which will advance reductions in whole building emissions for new and existing buildings. The reuse of existing buildings is vital to overall emissions reductions as retrofits can save 50-70% of embodied carbon over new construction. 

Vanessa Hostick, AIA, is a sustainable design leader with HOK. She is the global AIA 2030 manager for HOK and served as Working Group co-chair in 2022-23.