Eui Calculator - Site kBtu per Square Foot Annually

An EUI calculator turns a building's annual electricity, natural gas, and other fuel use into a single site energy use intensity score in kBtu per square foot per year, so buildings of different sizes can be compared on a level playing field. Reported in kWh per square meter per year, the same metric lets international readers benchmark offices, schools, retail, and multifamily housing using the formula ENERGY STAR Portfolio Manager and the EIA's CBECS survey use. Use this calculator when you want a quick site EUI without setting up an account, when sizing the impact of an efficiency upgrade, or when a tenant or buyer asks for a property's energy profile.

• • Benchmarking a small commercial property: Plug in 12 months of electricity, gas, and conditioned floor area to see whether the building is below, near, or above a typical CBECS range.
• • Estimating the size of an efficiency upgrade: Compare the current EUI to a target like ENERGY STAR 75 and model how much kBtu the upgrade has to remove.
• • Translating utility bills for an international audience: Get both kBtu per square foot per year and the metric kWh per square meter per year equivalent so the result reads naturally in the US and abroad.
• • Preparing a tenant or buyer summary: Run the calculator with the past year's utility totals, add a blended dollars per kBtu, and you have a one-line cost and intensity figure to share.

EUI is the workhorse number behind ENERGY STAR scores, green building certifications, and most US utility retro-commissioning reports. This page takes the same inputs Portfolio Manager accepts and applies the same EPA-published conversion factors. Because EUI is normalized by floor area, a 1,500 square foot cafe and a 50,000 square foot warehouse end up with comparable scores, which is why it drives which projects get funded first in many commercial portfolios.

For a single-family version of the same idea, the home energy audit calculator walks through the appliance-level inputs that drive a residential EUI.

The EUI calculator converts every fuel to kBtu, adds them up, and divides by the conditioned floor area, exactly the way ENERGY STAR Portfolio Manager defines site EUI. The metric result is the same number re-expressed in kWh per square meter per year using a single published conversion factor.

• Electricity (kWh): Total annual electricity from your utility bill, converted to kBtu by multiplying by 3.412 (the ENERGY STAR Portfolio Manager factor).
• Natural gas (therms): Total annual therms from your gas bill. One therm equals 100 kBtu per the U.S. Energy Information Administration.
• Natural gas (CCF): Use this if your bill shows CCF, which is 100 cubic feet of gas. One CCF equals roughly 103 kBtu.
• Other fuel (kBtu): Fuel oil, propane, district steam, or any other source, already in kBtu.
• Floor area (sq ft or sq m): Conditioned floor area. Square meter values are converted to square feet before the main calculation.

The calculator also produces a metric equivalent by multiplying the site EUI by 3.155, the same factor ENERGY STAR Portfolio Manager uses to convert kBtu per square foot into kWh per square meter. The annual cost line multiplies total kBtu by the optional blended rate for a quick tenant or board figure.

According to U.S. EPA ENERGY STAR Portfolio Manager, site EUI is the energy a building uses at the meter divided by its floor area, and is reported in kBtu per square foot per year.

According to U.S. Energy Information Administration, one therm of natural gas equals 100 kBtu and one CCF of natural gas equals about 103 kBtu.

After the site EUI comes out, the carbon footprint calculator turns the same kWh and therm totals into an emissions estimate for sustainability reporting.

Four terms come up in every EUI report. Knowing them helps you read an ENERGY STAR score, a CBECS table, or a retrofit proposal without translating on the fly.

Run the calculator in under a minute if you already have 12 months of utility data and the conditioned floor area to hand. The steps below line up with the order Portfolio Manager asks for the same numbers.

1. 1 Pull 12 months of utility bills: Find the total kWh of electricity and the total therms (or CCF) of natural gas the building used over the past year. If you only have monthly figures, add them up.
2. 2 Confirm the conditioned floor area: Use the gross conditioned area from a leasing plan, an assessor record, or a Portfolio Manager entry. Garages, attics, and unconditioned storage should be left out.
3. 3 Enter the values into the calculator: Type electricity, gas, and any other fuel into the matching fields. Choose square feet or square meters, then pick the closest property type so the benchmark is meaningful.
4. 4 Read the site EUI and the metric equivalent: The primary result is in kBtu per square foot per year. The metric line shows the same number in kWh per square meter per year for international readers.
5. 5 Add a blended rate to see annual cost: If you want a dollar figure, type a blended dollars per kBtu. Owners often use the average of their last 12 months of fuel and electric costs divided by total kBtu.
6. 6 Compare the result to the benchmark: Use the benchmark line to see how the building stacks up against the typical CBECS range for the property type you selected.

A 5,000 square foot office that uses 50,000 kWh and 1,000 therms a year returns a site EUI of 54 kBtu per sq ft per year, which the benchmark line will describe as below the typical range for offices.

Where insulation is the cheapest lever, the home insulation ROI calculator converts the kBtu it removes into a payback period and lifetime savings.

A site EUI gives you a comparable, repeatable number for any building, which is why it is the metric of choice for owners, tenants, lenders, and program administrators.

• • Compares buildings of different sizes: Because EUI is normalized by square foot, a small cafe and a 200,000 square foot warehouse can be ranked on the same scale.
• • Speaks the language of ENERGY STAR and CBECS: The result is the same metric Portfolio Manager and the EIA use, so the calculator output drops straight into a benchmarking submission.
• • Reveals the size of an efficiency upgrade: Subtract the post-retrofit EUI from the current one and you have a kBtu per sq ft per year gap to close.
• • Produces a metric equivalent for global teams: The kWh per sq m per year line keeps an international facilities team, an investor, and a U.S.-based property manager looking at the same number.
• • Translates utility bills into one number: The site EUI summary sits at the top of tenant and buyer decks, replacing pages of monthly bills with a single comparable score.

Once the benchmark shows the gap, the solar panel savings calculator sizes the PV system that would close it and the bill savings that would follow.

EUI can vary widely across properties, so it helps to know what typically drives it up or down before drawing conclusions.

• • EUI is a single number and hides the difference between a well-insulated building and one that wastes energy on a few big loads. Pair EUI with a look at the underlying end uses before approving a retrofit.
• • This EUI calculator uses the published ENERGY STAR and EIA conversion factors, but it does not weather-normalize results the way Portfolio Manager does, so a mild or severe year can shift the score by several kBtu per square foot.

According to the U.S. EPA ENERGY STAR benchmarking metrics, the 2018 CBECS places the median site EUI for U.S. office buildings at about 80 kBtu per square foot per year, with K-12 schools near 50 and hospitals above 220.

Appliance and lighting changes move the meter most for offices and small retail, and the ENERGY STAR appliance savings calculator shows the annual kWh each swap removes.