Energy Use Intensity (EUI): The Complete Guide

Energy Use Intensity, EUI, is one of the most important metrics in commercial real estate, and one of the least understood outside of technical circles. If you are managing a building portfolio in 2026, EUI is a number you need to know, track and actively work to reduce.

This guide explains what it is, how to calculate it, what a good score looks like, and how to bring it down.

What Is Energy Use Intensity?

EUI measures how much energy a building uses per square meter of floor area per year. It is typically expressed in kilowatt-hours per square meter per year (kWh/m²/year).

The formula is simple:

EUI = Total annual energy consumption (kWh) ÷ Total floor area (m²)

A building that consumes 500,000 kWh of energy per year and has 5,000 square metres of floor area has an EUI of 100 kWh/m²/year.

EUI normalizes energy consumption by size, which makes it useful for comparing buildings of different scales, a 500 square meter office and a 50,000 square meter office block are not directly comparable on total consumption, but their EUI scores can be benchmarked against each other and against sector averages.

Why EUI Matters

EUI has become a central metric in commercial real estate for three reasons.

Regulation: The EU's Energy Performance of Buildings Directive and national energy performance certificate (EPC) systems use energy intensity as the basis for building ratings. A high EUI typically means a poor EPC rating, which increasingly affects a building's ability to be leased, financed and sold.

Investment: Institutional investors and ESG frameworks (GRESB, EU Taxonomy, SFDR) use EUI as a benchmark for portfolio performance. Buildings with high EUI scores are increasingly viewed as stranded asset risks.

Operations: EUI is the most practical metric for tracking efficiency improvement over time. It accounts for changes in floor area, normalizes for weather variation (when site EUI is adjusted for climate), and provides a consistent basis for comparing performance across a portfolio.

Types of EUI

There are two variants worth understanding.

Site EUI measures the energy consumed at the building, what arrives through the meter. It is the simplest to calculate and the most commonly used.

Source EUI accounts for the energy required to generate and deliver the energy consumed at the building, including transmission losses and generation inefficiencies. Source EUI gives a fuller picture of a building's total environmental impact but requires additional data and assumptions.

For most practical purposes (benchmarking, EPC ratings, ESG reporting) site EUI is the relevant figure.

What Is a Good EUI?

EUI benchmarks vary significantly by building type, climate and age. As a general guide for commercial buildings in Northern Europe:

• Below 100 kWh/m²/year — highly efficient, likely to meet current and near-future regulatory thresholds
• 100 to 150 kWh/m²/year — reasonable performance, improvement opportunities exist
• 150 to 250 kWh/m²/year — below average, improvement required to meet tightening standards
• Above 250 kWh/m²/year — poor performance, significant investment likely needed

These are rough benchmarks. The relevant comparison is always against buildings of the same type and climate zone, a 24-hour data centre will have a much higher EUI than an office building, and that is expected.

The EU Taxonomy for sustainable finance sets specific EUI thresholds for buildings to qualify as sustainable assets, typically the top 15 percent of the national building stock. In most EU markets, this corresponds to an EUI below approximately 70 to 90 kWh/m²/year for offices.

What Drives a High EUI

Understanding why a building has a high EUI is the starting point for reducing it. The most common causes are:

Inefficient HVAC operation: Heating, cooling and ventilation running on fixed schedules regardless of occupancy and weather, the single biggest driver of unnecessary energy consumption in most commercial buildings.

Poor building envelope: Inadequate insulation, single glazing, air leaks, all of which increase the heating and cooling load the building needs to maintain.

Outdated equipment: Old chillers, boilers and air handling units that operate at significantly lower efficiency than modern equivalents.

24-hour or extended-hours operation: Buildings that run continuously or for long hours will have higher EUI than those with predictable occupancy windows, though this is a characteristic of use rather than inefficiency per se.

High plug loads: Data centers, laboratories and catering facilities generate significant heat loads that require additional cooling, raising EUI regardless of building fabric quality.

How to Reduce EUI

Reducing EUI requires addressing its drivers in order of impact and cost-effectiveness.

AI-Powered HVAC Optimization

For most commercial buildings, this is the highest-impact, fastest-payback intervention. AI systems like Myrspoven's myCoreAI continuously adjust heating, cooling and ventilation setpoints based on real-time conditions, occupancy, weather forecasts, energy prices, eliminating the waste that fixed schedules produce.

Typical EUI reductions from AI optimization are 20 to 25 percent on the HVAC component of consumption, which, given that HVAC accounts for 40 to 60 percent of total energy use, translates to a 10 to 15 percent reduction in overall EUI. In absolute terms, a building with an EUI of 180 kWh/m²/year might achieve 155 to 160 kWh/m²/year through AI optimization alone, potentially enough to move up an EPC band.

Lighting Upgrades

LED replacement reduces lighting energy consumption by 50 to 70 percent. Combined with occupancy sensors and daylight dimming, the impact on overall EUI is typically 5 to 10 percent.

Building Envelope Improvements

Improving insulation, upgrading glazing and addressing air leaks reduces the heating and cooling load. The EUI impact depends on the severity of the existing deficiencies, buildings with very poor envelopes can see reductions of 20 percent or more; those with reasonable existing fabric will see smaller gains.

Electrification and Renewable Energy

Switching from gas heating to heat pumps powered by renewable electricity reduces source EUI significantly, even if site EUI remains similar. For buildings reporting against frameworks that use carbon intensity rather than pure energy consumption, this can be highly impactful.

Behavioural and Operational Measures

Reducing set temperatures by one or two degrees outside of core hours, switching off equipment that runs unnecessarily, optimizing start and stop times, these measures contribute to EUI reduction but typically deliver 2 to 5 percent improvements rather than transformational change. They are worth doing but should not substitute for technology-led optimization.

Tracking and Reporting EUI

To track EUI effectively you need accurate consumption data, ideally from smart meters with at least monthly readings, and ideally with submetering that distinguishes HVAC, lighting and other loads.

Consumption data should be weather-normalized before comparing across years. A building will consume more energy in an unusually cold winter than a mild one, even if efficiency has improved. Weather normalization removes that noise and allows true like-for-like comparison.

Most ESG reporting frameworks require EUI data to be reported annually, with a verified baseline and year-on-year comparison. AI building management systems generate this data automatically as a by-product of operation, eliminating the manual data collection process that has historically made EUI reporting burdensome.

The Bottom Line

EUI is the most useful single metric for understanding and improving a building's energy performance. It enables comparison, drives accountability and underpins regulatory compliance.

Buildings with high EUI are facing growing financial pressure, from regulation, investors and tenants. Those that bring their EUI down systematically, starting with the highest-impact interventions, are building resilient, future-proof assets.

The starting point is understanding where you are. From there, the path to improvement is clearer than most people expect.

Want to understand the EUI profile of your portfolio and identify the fastest route to improvement? Talk to our team.