Energy Use Intensity (EUI) Calculator

Total Annual Energy Consumption:

Total Floor Area:

1. What is an Energy Use Intensity (EUI) Calculator?

Definition: This calculator determines the Energy Use Intensity (EUI) of a building, which is the annual energy consumption per unit of floor area.

Purpose: It is used to assess a building's energy efficiency, compare energy performance across buildings, and identify opportunities for energy savings.

2. How Does the Calculator Work?

The calculator uses the following formula:

Energy Use Intensity (EUI): \[ \text{EUI} = \frac{\text{Total Annual Energy Consumption}}{\text{Total Floor Area}} \]

Where:

\( \text{EUI} \): Energy Use Intensity (kWh/m²/yr or kBtu/ft²/yr)
Total Annual Energy Consumption: Energy used in a year (in various units)
Total Floor Area: Area of the building (m² or ft²)

Unit Conversions:

Energy to kWh:
1 J = \( \frac{1}{3600000} \) kWh
1 kJ = \( \frac{1}{3600} \) kWh
1 MJ = 0.277778 kWh
1 Wh = 0.001 kWh
1 kWh = 1 kWh
1 MWh = 1000 kWh
1 BTU = 0.000293071 kWh
1 kBTU = 0.293071 kWh
1 MMBTU = 293.071 kWh
Area to m²:
1 ft² = 0.092903 m²
EUI Conversions:
1 kWh = 3.41214 kBtu
1 m² = \( \frac{1}{0.092903} \) ft²

Steps:

Enter the total annual energy consumption and select the unit (J, kJ, MJ, Wh, kWh, MWh, BTU, kBTU, MMBTU).
Enter the total floor area and select the unit (m² or ft²).
Convert energy consumption to kWh and floor area to m².
Calculate the EUI in kWh/m²/yr using the formula \( \text{EUI} = \frac{\text{Total Annual Energy Consumption}}{\text{Total Floor Area}} \).
Convert the EUI to kBtu/ft²/yr by converting energy to kBtu and area to ft².
Display the EUI in both units.

3. Importance of EUI Calculation

Calculating EUI is crucial for:

Energy Efficiency: Identifies buildings with high energy use, prompting improvements.
Cost Savings: Lower EUI values can lead to reduced energy bills.
Environmental Impact: Helps reduce energy consumption, lowering carbon emissions.

4. Using the Calculator

Examples:

Example 1: Total Annual Energy Consumption = 10000 kWh, Total Floor Area = 100 m²:
- EUI (kWh/m²/yr): \( \frac{10000}{100} = 100 \, \text{kWh/m}^2/\text{yr} \)
- Energy in kBtu: \( 10000 \times 3.41214 = 34121.4 \, \text{kBtu} \)
- Area in ft²: \( 100 \div 0.092903 \approx 1076.39 \, \text{ft}^2 \)
- EUI (kBtu/ft²/yr): \( \frac{34121.4}{1076.39} \approx 31.70 \, \text{kBtu/ft}^2/\text{yr} \)
Example 2: Total Annual Energy Consumption = 1000 kBTU, Total Floor Area = 1000 ft²:
- Energy in kWh: \( 1000 \times 0.293071 = 293.071 \, \text{kWh} \)
- Area in m²: \( 1000 \times 0.092903 = 92.903 \, \text{m}^2 \)
- EUI (kWh/m²/yr): \( \frac{293.071}{92.903} \approx 3.15 \, \text{kWh/m}^2/\text{yr} \)
- Energy in kBtu: \( 293.071 \times 3.41214 \approx 1000 \, \text{kBtu} \)
- EUI (kBtu/ft²/yr): \( \frac{1000}{1000} = 1 \, \text{kBtu/ft}^2/\text{yr} \)

5. Frequently Asked Questions (FAQ)

Q: What is a good EUI value?
A: A good EUI varies by building type and climate. For example, an efficient office building might have an EUI of 50-100 kWh/m²/yr or 15-30 kBtu/ft²/yr, while a residential building might be lower.

Q: How can I reduce my building's EUI?
A: Improve insulation, use energy-efficient lighting and appliances, implement smart energy management systems, and reduce unnecessary energy use.

Q: Does the calculator account for different energy sources?
A: No, this calculator assumes all energy is in a single unit. If you use multiple energy sources (e.g., electricity, gas), convert them to a common unit before inputting.

Favorite