What is the energy use intensity (EUI)? "Energy Performance Metrics"

Energy use intensity, or EUI. Primarily, the EUI expresses a building’s energy use as a function of its size or other characteristics. 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 (measured in kBtu or GJ) by the entire gross floor area of the building. Generally, a low EUI signifies good energy performance. However, individual property types will always use more energy than others. For example, an elementary school uses relatively little power compared to a hospital.

In the past two decades, our industry has seen a significant shift toward a focus on energy efficiency and sustainability. To accurately gauge whether this shift has had a quantifiable impact, terms such as Energy Use Intensity (EUI), Power Use Effectiveness (PUE), and Gallons/Day have become commonplace. These simplified metrics are useful tools in tracking the performance of a building, but they have limits. For example, an airport may be a hub for popular airlines and see higher traffic
than a similarly-sized airport on the other side of the city. The resulting higher energy use per square foot would be a mark of failure rather than a success of building performance. But that’s not accurate. To be truly useful, we need to rethink our metrics, not to shift the goal posts, but to more accurately measure performance.

Performance metrics are vital in determining how efficiently or effectively a facility is operating or is designed to work. By compiling measured energy, water, and waste effluent data into databases such as ENERGY STAR Portfolio Manager, benchmarks can be established for various building types and buildings in different climates. Benchmarks are then used as starting points in designing new facilities or investigating energy cost savings opportunities in existing buildings.

Many individuals and groups are involved with a building over its lifetime, and all have different interests in and requirements for the construction. Although these interests differ, the value of using metrics reflects a small number of driving factors: Controlling energy costs and energy consumption, Minimizing environmental impacts,  Enhancing the image through marketing, and  Improving load forecasting, energy management, and reliability.

Sources:
Performance Metrics Tiers | Department of Energy. https://www.energy.gov/eere/buildings/performance-metrics-tiers
Energy Conservation Policy: sustainNU - Northwestern .... https://www.northwestern.edu/sustainability/program-areas/built-environment/energy-conservation.html
What is the energy use intensity (EUI)? | ENERGY STAR .... https://www.energystar.gov/buildings/facility-owners-and-managers/existing-buildings/use-portfolio-manager/understand-metrics/what-energy
New Thinking About Building Performance Energy Metrics .... https://www.glumac.com/new-thinking-performance-metrics/

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