Net Zero Energy Buildings

The Department of Energy (DOE), through its High Performance Commercial Buildings research, is leading the way in developing net zero energy buildings (ZEBs). On this page, you will learn more about net ZEB definitions and have access to examples of ZEBs.

Defining Net Zero Energy Buildings

A net ZEB produces as much energy as it uses over the course of a year. Net ZEBs are very energy-efficient buildings, with the remaining low energy needs typically met through the use of on-site renewable energy.

There are a number of specific definitions for net ZEBs, depending on goals. Each type of ZEB has value in reducing energy impact. A building may meet multiple ZEB definitions, increasing its merit as a ZEB. For more information about these definitions, see the report Zero Energy Buildings: A Critical Look at the Definition (PDF 477 KB). Download Adobe Reader. Following is a summary of the definitions:

Net Zero Site Energy

A site zero energy building produces at least as much energy as it uses in a year, when accounted for at the site. The measurement time frame is annual.

Net Zero Source Energy

A source zero energy building produces at least as much energy as it uses in a year, when accounted for at the source. Source energy refers to the primary energy required to generate and deliver the energy to the site. To calculate a building's total source energy, imported and exported energy is multiplied by the appropriate site-to-source conversion multipliers.

Net Zero Energy Costs

In a net zero energy costs building, the amount of money the utility pays the building owner for the energy the building exports to the grid is at least equal to the amount the owner pays the utility for the energy services and energy used over the year.

Net Zero Energy Emissions

A net zero energy emissions building produces at least as much emissions-free renewable energy as it uses from emission-producing energy sources annually. Carbon, NO_x, and SO_x are common emissions that ZEBs offset.

Near Zero Energy

A near zero energy building produces at least 75% of its required energy through the use of on-site renewable energy. Off-grid buildings that use some non-renewable energy generation for backup are considered near zero energy buildings because they typically cannot export excess renewable generation to account for fossil fuel energy use.

Examples of Zero Energy Buildings

The Zero Energy Buildings Database contains examples of zero energy buildings and details about these projects including:

• Financing
• Land use
• Site description
• Energy use overview.

Visit the ZEB Database to see a sample of zero energy buildings. We also encourage you to submit your own examples of zero energy buildings. If you’re entering a new ZEB, please be sure to include which ZEB definitions you met and how you met them. Also, please include information on the overview and energy pages to show the energy performance of your building.