Energy use intensity (EUI) is defined as?

• A. An expression of the annual energy used or calculated to be used by a building or building space per unit of gross floor area.
• B. The peak electrical demand of a building.
• C. Energy cost per year.
• D. The energy efficiency ratio.

Answer: (A)

Energy use intensity measures how much energy a building uses in a year relative to its size. It takes the total annual energy consumption for the building (all end-uses) and divides it by the gross floor area, giving units like kBtu per square foot per year or MJ per square meter per year. This size-normalized metric lets you compare energy performance across buildings of different sizes on a like-for-like basis.

The other options describe different concepts. Peak electrical demand looks at the highest power draw at a moment in time, not annual energy per area. Energy cost per year reflects money spent, not the amount of energy used. The energy efficiency ratio is a rate for a specific device (often cooling equipment), comparing output to input, rather than the building’s total annual energy use per area.