Energy Use Intensity (EUI) measures the total annual energy consumption of a building divided by its conditioned floor area, typically expressed in kilowatt-hours per square foot per year (kWh/sf/yr) or British thermal units per square foot per year (Btu/sf/yr). EUI provides a standardized metric for comparing energy performance across buildings of different sizes and types. This metric is essential for benchmarking building efficiency against similar properties and establishing energy reduction targets.
Technical Details
EUI calculations include all energy sources: electricity, natural gas, steam, and other fuels consumed within the building envelope. A typical office building in the United States has an EUI between 10 and 20 kWh/sf/yr, while well-designed efficient buildings may achieve 5 to 8 kWh/sf/yr. The metric accounts for weather normalization and operational differences to enable fair comparisons.
Practical Applications
Building owners use EUI to identify underperforming properties, track energy efficiency improvements over time, and comply with municipal energy benchmarking mandates. EUI is fundamental to LEED certification, Energy Star ratings, and local disclosure requirements in cities like New York and Washington DC. Understanding EUI helps facility managers prioritize capital investments in HVAC upgrades, insulation improvements, and control system optimization.