No one knows what a ‘net zero’ building actually means. The government has plans to change that

On its face, the concept of a zero-emissions building is straightforward. It’s a building that produces zero emissions. Right?

Well, yes, technically. But how it does so is less than clear, according to the Biden Administration. “There has been quite a lot of confusion in the market around the transition to zero-emissions buildings,” says Heather T. Clark, director of building emissions at the White House’s Climate Policy Office. “Many people were using terms like net zero, zero carbon, and other terms in a way that was very inconsistent and confusing.”

To bring some consistency and clarity, the White House and the Department of Energy are creating an official definition of what it means to be a zero-emissions building, what it takes to get there, and how that status can be proven. A draft definition was released late last year, and public comment is being sought until February 5.

“The Biden-Harris administration has set a goal to make zero emissions, resilient new construction and retrofits common practice by 2030,” says Clark, who notes the fact that the operation of buildings accounts for an estimated 30% of U.S. greenhouse gas emissions. “The definition will serve as a very clear market signal to help transition the building sector.”

The draft definition has three main pillars:

1. Buildings should be “highly energy efficient.”
2. Buildings should be free of on-site emissions from energy use.
3. Buildings should be powered solely by clean energy.  

The second pillar—zero emissions—is the heart of the definition and also the most straightforward. But the other pillars are equally crucial, according to Clark. An emissions-free building that hogs electricity is not much better than one still burning gas to power its furnace. A house with no on-site emissions is not making a big difference if all its electricity comes from a coal-fired power plant down the road. Nailing each of these three aspects is the best way to bring the building sector’s carbon footprint down, the definition suggests.

Clark says her office has met with hundreds of stakeholders in the architecture, engineering, construction, and commercial real estate industries, as well as building owners. She’s hoping the feedback that comes between now and early February helps refine the definition’s shape and provides advice on whether energy efficiency targets are too high or too low. The draft definition aims for buildings that are 10% more efficient than what is required by the latest building code, a target that’s expected to move over time as the code improves.

“If we are all on the same page in terms of where we’re trying to go, that clear line in the sand, that alignment really helps create market action,” Clark says.

For example, a clearly defined zero-emissions building could help a developer market its apartments to climate-conscious buyers. A proposed and verifiable zero-emissions building may also be more attractive to climate-focused investors compared to a building that may still need a gas hookup. Knowing a building is intended to be zero emissions helps its designers and builders work around fixed targets, not moving goal posts.

There’s already widespread industry interest in the definition. A recent statement of support for the definition was signed by representatives at 69 architecture, engineering, and general contracting firms across the U.S. The American Institute of Architects (AIA), which represents nearly 100,000 architecture professionals, is also supportive. “Having a greater definition is mission critical, so people know exactly what to be doing and what not to be doing so we can really move the needle on these issues,” says AIA president Kimberly Dowdell.

The definition is more than a bunch of federalese destined to sit in a rule book in Washington D.C. Clark says discussions are already underway with third party green building certification programs, like the U.S. Green Building Council’s LEED system, to have the zero emissions building definition woven into the way they assess projects.

That could happen soon. After the public comment period ends in early February, Clark says her office and the Department of Energy are looking to finalize the definition by the end of March. Buildings will soon be able to officially declare that they produce zero emissions. It’s a label, sure, but also a standard that could reset peoples’ expectations for what buildings should do.

“Because of the urgency of the climate crisis, we are moving very quickly on this definition so that we can create alignment, and so that the building sector can really move forward,” Clark says.