Energy benchmarking is the process of comparing the energy use of a building with the energy use of buildings of similar type; for example, comparing the energy use per square foot of one elementary school with average energy use for general elementary schools. This process involves finding the energy use index (EUI) of a building. EUI is the energy use (in kBtu) per square foot; EUI includes both electric energy use and natural gas energy use.
Often times the first step in analyzing the energy use of a building is benchmarking it; benchmarking a building serves as a way to measure energy performance. When benchmarking, seeing how a building stacks up to an average is a good way to gauge how well (or poor) the building itself is performing. Energy Star Portfolio Manager has a technical reference which contains a large listing of types of buildings, and the corresponding national median EUI of these buildings. This technical reference serves as a great tool in checking how a building is performing.
Once the building is benchmarked and the EUI is calculated and compared, an idea of energy efficiency priorities can be compiled. Weaker buildings (high EUI) can begin to work toward the goal of efficiency with projects such as: lighting, heating and cooling equipment improvements, process/occupancy changes, etc. Stronger performing buildings (low EUI) can work to continue their energy efficiency practices and search for deeper energy efficiency measures to implement.