To offer more clarity to the building industry the U.S. Department of Energy (DOE) has released A Common Definition of Zero Energy Buildings, which states that a net zero energy (NZE) building is “an energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy.”

In collaboration with the National Institute of Building Sciences, the DOE spent more than a year refining the language through a stakeholder engagement process. The results also provide guidelines for measurement and implementation that explain how to apply the definition to building projects.

“Reducing energy use in buildings must be a major part of the solution as we work to combat the escalating costs and impacts of climate change,” said Brendan Owens, chief engineer at the U.S. Green Building Council. “While we are making significant progress to save energy in buildings, this Zero Energy Building definition developed by DOE helps increase expectations and orient the buildings industry towards even greater achievements.

David Underwood, president of ASHRAE, foresees the global marketplace using this new interpretation as a tool to push long term sustainability. According to the New Buildings Institute (NBI), the number of NZE buildings across the U.S. has doubled from 2012 to 2014. As NZE building multiply, the inconsistency of the definition has been known to cause market confusion.

“NIBS and USDOE have created a set of clear and concise definitions for zero energy buildings that will help to narrow the broad array of terminology currently used in the industry,” added Ralph DiNola, chief executive officer of NIB. “These consistent definitions will contribute to the growth of zero energy building construction across this country.”