The EUI (Energy Use Intensity) Calculator measures the energy efficiency of a building by calculating the amount of energy it consumes per unit of floor area over the course of a year. EUI is a widely used metric in the fields of energy management, green building certification, and real estate performance benchmarking.
By analyzing EUI, building owners, facility managers, engineers, and sustainability professionals can identify inefficient buildings, compare performance across properties, set energy reduction goals, and track improvements over time. It also supports compliance with programs like ENERGY STAR, LEED, and government-mandated energy disclosure laws.
Formula of EUI (Energy Use Intensity) Calculator
EUI = Total Annual Energy Consumption / Gross Floor Area
Where:
- EUI is expressed in either kBtu per square foot per year (kBtu/ft²/year) or kWh per square meter per year (kWh/m²/year)
- Total Annual Energy Consumption is the sum of all energy types (electricity, gas, oil, etc.) used by the building in a year, converted to a single unit (kBtu or kWh)
- Gross Floor Area is the total enclosed floor area of the building, including all spaces served by energy systems
Conversion:
1 kWh = 3.412 kBtu
Use this conversion to maintain unit consistency if your energy data includes mixed units.
Helpful Reference Table
Below is a reference table to help estimate EUI values for various types of buildings using standard benchmarks.
| Building Type | Typical EUI (kBtu/ft²/year) | Equivalent (kWh/m²/year) |
|---|---|---|
| Office (Standard) | 77 | 243 |
| Hospital | 234 | 736 |
| School (K-12) | 50 | 158 |
| Retail Store | 93 | 293 |
| Apartment (Multifamily) | 58 | 183 |
These values provide a starting point to compare your calculated EUI against common industry averages and determine whether a building is above or below expected efficiency.
Example of EUI (Energy Use Intensity) Calculator
Let’s calculate the EUI for an office building that uses 950,000 kWh of electricity annually and has a gross floor area of 45,000 ft².
Step 1: Convert energy to kBtu
Total Energy = 950,000 × 3.412 = 3,241,400 kBtu
Step 2: Apply the formula
EUI = 3,241,400 / 45,000 ≈ 72.03 kBtu/ft²/year
Result: The building’s Energy Use Intensity is approximately 72.03 kBtu/ft²/year, which is slightly below the typical EUI for office buildings, indicating relatively good performance.
Most Common FAQs
EUI helps evaluate how efficiently a building uses energy relative to its size. It supports energy audits, helps identify savings opportunities, and is critical for sustainability reporting and benchmarking.
A "good" EUI depends on building type, climate, and usage patterns. Generally, the lower the EUI, the better the energy performance. However, high-intensity buildings like hospitals naturally have higher EUI values.
Yes. EUI calculations should include all energy consumed by the building, such as electricity, natural gas, fuel oil, and district heating or cooling. Each source should be converted to a consistent energy unit.