ENERGY STAR® Portfolio Manager is a free online tool developed by the U.S. Environmental Protection Agency (US EPA) that allows you to track and assess energy and water use across your entire portfolio of buildings in a secure online environment. With Portfolio Manager, you can calculate the building's energy performance, compare it with similar buildings and monitor it over time. When you benchmark a building in Portfolio Manager, one of the key metrics you'll see is energy use intensity, or EUI.
The EUI expresses a building’s energy use as a function of its size or other characteristics. For most property types in Portfolio Manager, the EUI is expressed as energy per square foot per year. It’s calculated by dividing the total energy consumed by the building in one year by square footage. For many building types, Portfolio Manager calculates the ENERGY STAR® rating, which indicates how efficiently buildings use energy on a 1-100 scale, where a score of 50 indicates average energy performance. Buildings with a score of 75 or better are top performers and may be eligible for the ENERGY STAR® certification. Some building types are currently not eligible to receive an ENERGY STAR® score, but can still benefit from benchmarking, as Portfolio Manager calculates other energy performance metrics such as EUI.