Eui Calculator

Energy Use Intensity, or EUI, is a critical metric for understanding and managing a building's energy consumption. It serves as the building's "miles per gallon" rating, providing a simple yet powerful way to benchmark performance, identify opportunities for improvement, and track progress over time. Our EUI Calculator makes it easy to determine this value for your property. By normalizing energy consumption for building size, EUI allows for fair comparisons between different buildings, regardless of their dimensions.

What is Energy Use Intensity (EUI)?

Energy Use Intensity (EUI) is a measure of a building's annual energy consumption relative to its total floor area. It is typically expressed in thousands of British Thermal Units (kBTU) per square foot per year (kBTU/ft²). This metric accounts for all energy sources used in the building, including electricity, natural gas, and district heating or cooling. By creating a standardized value, EUI allows building owners, facility managers, and sustainability professionals to quickly assess how efficiently their property uses energy compared to similar buildings or to established energy performance benchmarks.

A low EUI indicates high energy efficiency, while a high EUI suggests that there are significant opportunities for energy savings. The U.S. Environmental Protection Agency (EPA) uses EUI as a key component of its ENERGY STAR program to rate the energy performance of commercial buildings.

How to Use the EUI Calculator

Our calculator simplifies the process of finding your building's EUI. Follow these steps to get your result:

1. Gather Your Energy Data: Collect your building's energy consumption data for a full 12-month period. You will need the total consumption for all energy types (e.g., kWh for electricity, therms or cubic feet for natural gas).
2. Input Annual Energy Consumption: Enter the total energy consumed in the designated field. Use our tool to convert different energy units (like kWh or Gigajoules) into kBTU if necessary.
3. Enter Building Area: Input the total gross floor area of your building. You can use either square feet or square meters.
4. Calculate EUI: Click the "Calculate EUI" button. The calculator will instantly display your building's EUI in kBTU per square foot per year.

The Formula Behind EUI

The calculation for Energy Use Intensity is straightforward. The calculator uses the following formula:

EUI = (Total Annual Energy Consumption in kBTU) / (Total Building Floor Area in ft²)

To ensure accuracy, the calculator automatically handles the conversion of different energy and area units into the standard kBTU and square feet required for the formula.

Practical Example of EUI Calculation

Let's walk through an example to see how the EUI Calculator works in a real-world scenario.

• Building Type: Office Building
• Total Floor Area: 50,000 square feet
• Annual Electricity Consumption: 900,000 kWh
• Annual Natural Gas Consumption: 2,000,000 kBTU (or 20,000 therms)

Step 1: Convert all energy to kBTU.

First, we convert the electricity consumption from kWh to kBTU. The conversion factor is 1 kWh = 3.412 kBTU.

Electricity Energy = 900,000 kWh * 3.412 kBTU/kWh = 3,070,800 kBTU

Step 2: Sum all energy sources.

Next, we add the energy from electricity and natural gas together to get the total annual energy consumption.

Total Annual Energy = 3,070,800 kBTU + 2,000,000 kBTU = 5,070,800 kBTU

Step 3: Calculate the EUI.

Finally, we divide the total energy consumption by the building's floor area.

EUI = 5,070,800 kBTU / 50,000 ft² = 101.42 kBTU/ft²

This result can then be compared to the national average EUI for office buildings (around 91 kBTU/ft²) to understand its performance. A score of 101.42 indicates that this building is slightly less efficient than the average office building.

Why EUI is Important

• Benchmarking: EUI is the most effective way to compare your building's energy performance against similar buildings in your region or across the country.
• Cost Savings: Identifying a high EUI is the first step toward implementing energy-saving measures that can significantly reduce operational costs. You might consider using a LED Savings Calculator to see how lighting upgrades can help.
• Sustainability Goals: Tracking EUI over time allows organizations to measure their progress toward sustainability and carbon reduction targets.
• Regulatory Compliance: Many cities and states now require buildings to report their energy use, and EUI is the standard metric for this type of benchmarking.

Frequently Asked Questions (FAQ)

What is a good EUI?

A "good" EUI varies dramatically by building type and climate zone. For example, a hospital, which operates 24/7 with energy-intensive equipment, will have a much higher EUI than a warehouse. Generally, a lower EUI is always better. The U.S. Department of Energy provides benchmark EUI values for various building types.

How can I improve my building's EUI?

Improving EUI involves reducing energy consumption. Common strategies include upgrading to energy-efficient lighting (like LEDs), optimizing HVAC systems, improving insulation, and installing smart building controls. Tools like the Electricity Cost Calculator can help identify which appliances contribute most to your consumption.

Is EUI the same as energy cost?

No. EUI measures energy *consumption* (kBTU/ft²), while energy cost measures the price paid for that energy ($/ft²). While related, they are different metrics. A building in a region with low utility rates might have a low energy cost but a high EUI, indicating it is inefficient but benefits from cheap energy. Conversely, you can also use tools like a Gas vs Electric Dryer Calculator to compare the cost-efficiency of different appliance types.

For more detailed information on building energy performance, you can visit the U.S. Energy Information Administration (EIA) website, which publishes extensive data on commercial building energy consumption.