How is energy use intensity (EUI) defined for a building?

• A. EUI equals total annual site energy use divided by number of occupants.
• B. EUI equals total annual site energy use divided by floor area.
• C. EUI equals peak power multiplied by operating hours.
• D. EUI equals energy cost per square foot per year.

Answer: (B)

EUI measures how much energy a building uses per unit of floor area over a year. It is calculated by taking the total annual site energy use (all energy consumed on site, including electricity, natural gas, steam, etc.) and dividing it by the building’s floor area. This normalization lets you compare different buildings regardless of size or occupancy, using units like kBtu/ft²/year or kWh/m²/year. It isn’t about energy cost or peak power; it’s about energy use per area.