The U.S. Department of Energy (DOE) recently released a common definition of a zero-energy building, providing clarity and consistency on key issues that increasingly were the source of market confusion.
In collaboration with the National Institute of Building Sciences, the DOE worked with a large and diverse set of building-industry stakeholders over a period of a year and a half to develop the definition. The definition, along with guidance for measurement and implementation, is contained in the report “A Common Definition for Zero Energy Buildings.”
The report defines a zero-energy building, also known as a “net zero energy” or “zero net energy” building, as “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.”
Generally speaking, a zero-energy building produces enough renewable energy to meet its own annual energy-consumption requirements. Long-term advantages of this include lesser environmental impacts, lower operating and maintenance costs, better resilience to power outages and natural disasters, and improved energy security.
Reducing energy consumption in new and existing buildings can be accomplished through various means, including integrated design, energy-efficiency retrofits, reduced plug loads, and energy-conservation programs.
“For too long, uncertainty in the marketplace around this issue has been a barrier to many private and state efforts in the move toward zero-net-energy buildings,” David Terry, executive director of the National Association of State Energy Officials, said. “This action supports existing state-energy-office efforts, which have resulted in zero-net-energy schools in Kentucky, state office buildings in Iowa, and new homes in many states. Providing standard definitions will help states and private-sector partners expand the pace of zero-net-energy construction.”
David Underwood, president of ASHRAE, said: “The 53,000 worldwide members of ASHRAE have diverse interests in how to approach zero-energy buildings, but all share a desire to move this goal forward. This definition of zero-energy buildings will certainly become one of the tools used by the worldwide marketplace to move towards a sustainable future.”
To download “A Common Definition for Zero Energy Buildings,” go to http://energy.gov/eere/buildings/downloads/common-definition-zero-energy-buildings.