Energy Use Intensity (EUI) Calculator
Calculate energy use intensity euicalculator easily with our free tool. Get practical results, tips, and comparisons for everyday decisions.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
EUI = Total Energy (kBtu) / Gross Floor Area (sq ft)
Where EUI is Energy Use Intensity in kBtu per square foot per year, Total Energy is the sum of all energy sources converted to kBtu (electricity kWh x 3.412 + gas therms x 100), and Gross Floor Area is the total building floor area in square feet.
Worked Examples
Example 1: Office Building EUI Calculation
Problem:A 25,000 sq ft office building consumed 300,000 kWh of electricity and 5,000 therms of natural gas in a year. Calculate the site EUI and compare to benchmark.
Solution:Electricity in kBtu: 300,000 kWh x 3.412 = 1,023,600 kBtu\nNatural gas in kBtu: 5,000 therms x 100 = 500,000 kBtu\nTotal energy: 1,023,600 + 500,000 = 1,523,600 kBtu\nSite EUI: 1,523,600 / 25,000 = 60.9 kBtu/sqft\nOffice benchmark: 78 kBtu/sqft\nPerformance: 60.9 / 78 = 78% of benchmark (Good)
Result:Site EUI: 60.9 kBtu/sqft | 22% better than the median office benchmark of 78 kBtu/sqft
Example 2: Hospital Source EUI Analysis
Problem:A 100,000 sq ft hospital uses 2,000,000 kWh of electricity and 40,000 therms of natural gas annually. Calculate site and source EUI.
Solution:Electricity site kBtu: 2,000,000 x 3.412 = 6,824,000 kBtu\nGas site kBtu: 40,000 x 100 = 4,000,000 kBtu\nTotal site kBtu: 10,824,000 kBtu\nSite EUI: 10,824,000 / 100,000 = 108.2 kBtu/sqft\nSource electricity: 6,824,000 x 2.80 = 19,107,200 kBtu\nSource gas: 4,000,000 x 1.05 = 4,200,000 kBtu\nSource EUI: 23,307,200 / 100,000 = 233.1 kBtu/sqft
Result:Site EUI: 108.2 kBtu/sqft | Source EUI: 233.1 kBtu/sqft | Below the hospital median of 250 (Good)
Frequently Asked Questions
What is Energy Use Intensity (EUI) and why does it matter?
Energy Use Intensity (EUI) is a metric that measures a building's energy consumption relative to its size, expressed in kBtu per square foot per year. It provides a standardized way to compare the energy performance of different buildings regardless of their size. EUI matters because it helps building owners, managers, and policymakers identify energy-efficient and energy-wasteful buildings. Lower EUI values indicate better energy performance, meaning the building uses less energy per square foot. This metric is central to energy benchmarking programs, green building certifications like LEED and ENERGY STAR, and many local building performance standards that cities are adopting.
What is the difference between site EUI and source EUI?
Site EUI measures the energy consumed at the building location, counting each unit of electricity and gas equally based on what the meter reads. Source EUI accounts for the total energy required to generate, transmit, and deliver that energy to the building. Electricity has significant transmission and generation losses, so its source multiplier is approximately 2.80, meaning for every 1 kBtu of electricity used on-site, about 2.80 kBtu of primary energy was consumed at the power plant. Natural gas has a much lower source multiplier of about 1.05 since it arrives relatively directly. Source EUI gives a more complete picture of total environmental impact and is the metric used by ENERGY STAR Portfolio Manager for benchmarking.
What are typical EUI values for different building types?
EUI values vary dramatically by building type due to different operational requirements. Warehouses are the most efficient at around 28 kBtu per square foot since they require minimal conditioning. Schools average about 58 kBtu per square foot, while multifamily residential buildings come in around 65 kBtu per square foot. Offices typically fall around 78 kBtu per square foot, and hotels average about 95 kBtu per square foot due to 24-hour operations. Hospitals are energy-intensive at approximately 250 kBtu per square foot because of specialized equipment and strict ventilation requirements. Restaurants top the list at roughly 432 kBtu per square foot due to heavy cooking equipment and ventilation needs.
How can I reduce my building EUI effectively?
Reducing building EUI requires a systematic approach starting with an energy audit to identify the largest energy consumers. Common strategies include upgrading HVAC systems to high-efficiency models, improving building envelope insulation and air sealing, installing LED lighting with occupancy sensors and daylight harvesting controls, and optimizing building automation system schedules. Retro-commissioning existing systems can often achieve 10-15 percent energy savings with minimal capital investment. Adding renewable energy sources like rooftop solar panels reduces site energy consumption directly. Behavioral changes and tenant engagement programs can also contribute 5-10 percent savings by encouraging energy-conscious habits like turning off equipment when not in use.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy