Free Building Energy Intensity calculator with clear step-by-step results.
Energy use intensity normalises a building's annual consumption by its floor area, which is what makes a small office comparable with a large one. The metric is simply annual kWh ÷ m², reported as kWh/m²/yr in most of the world and kBtu/ft²/yr in North America. Comparing against a benchmark for the same building type is the point of the exercise; energy per occupied hour then separates a genuinely inefficient building from one that is merely used intensively.
Energy use intensity
EUI = annual energy (kWh) ÷ gross floor area (m²)
Normalised use
Per occupied hour = annual energy ÷ (occupied hours per week × 52)
Formal energy ratings and disclosure schemes define floor area, fuel weighting and climate normalisation in prescribed ways. Use an accredited assessor for any regulatory or certification purpose.
It depends entirely on building type and climate. Roughly 80-150 kWh/m²/yr is typical for offices, well over 300 for hospitals and data-heavy buildings, and under 50 for high-performance new build. Only compare like with like.
A building running 24/7 will always have a high EUI. Dividing by occupied hours reveals whether the consumption reflects genuine use or wasteful out-of-hours operation, which is where most quick savings are found.
Multiply kWh/m² by 0.3169. The conversion combines 3.412 kBtu per kWh with 10.764 ft² per m².