Enter the total energy consumed in a year and the total floor area of the building into the calculator to determine the Energy Use Index. This calculator can also evaluate any of the variables given the others are known.

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## Energy Use Index Formula

The following formula is used to calculate the Energy Use Index (EUI).

EUI = E / A

Variables:

- EUI is the Energy Use Index (kBtu/ft²)
- E is the total energy consumed in a year (kBtu)
- A is the total floor area of the building (ft²)

To calculate the Energy Use Index, divide the total energy consumed in a year by the total floor area of the building. The result is the Energy Use Index, which measures the energy efficiency of the building in kilo British thermal units per square foot per year.

## What is an Energy Use Index?

The Energy Use Index (EUI) is a benchmarking tool that measures the energy efficiency of a building by calculating the amount of energy used per square foot per year. It is expressed in units of energy per square foot per year and it’s used to compare the energy efficiency of different buildings or the same building over time. A lower EUI indicates better energy efficiency. It is a crucial component in energy management and sustainability strategies for commercial and residential properties.

## How to Calculate Energy Use Index?

The following steps outline how to calculate the Energy Use Index (EUI).

- First, determine the total energy consumed in a year (E) in kBtu.
- Next, determine the total floor area of the building (A) in ft².
- Next, gather the formula from above: EUI = E / A.
- Finally, calculate the Energy Use Index (EUI) in kBtu/ft².
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem:**

Use the following variables as an example problem to test your knowledge.

total energy consumed in a year (E) = 5000 kBtu

total floor area of the building (A) = 1000 ft²