Decoding Energy Use Intensity (EUI): A Key Metric for Sustainable Buildings

February 12, 2025 – 4 Min

As sustainability becomes an ever-greater requirement for businesses, Energy Use Intensity (EUI) has emerged as a key metric for measuring building efficiency. It calculates a building’s total annual energy consumption based on its overall floor area. The lower your commercial building’s EUI, the better its efficiency.

This article explores EUI and how you can leverage energy-efficient solutions to increase your building’s sustainability rating.

What is Energy Use Intensity (EUI)?

EUI is typically measured in one of two ways: Site EUI and Source EUI.  

Site EUI measures energy consumed on site, while Source EUI tracks energy usage back to its source and provides greater insight into a site’s overall environmental impact. Source EUI is typically used to measure projects with ambitious sustainability goals, with Site EUI more commonly used in most projects.

Calculating EUI

Energy Use Intensity is usually expressed in kWh/m2/year or kBtu/ft2/year and is calculated using this simple formula:

EUI = Total Energy Consumed Annually / Total Gross Floor Area

EUI can vary significantly between buildings based on their type, location, and usage patterns. For instance, hospitals and factories usually have higher EUIs than small office complexes.

How EUI impacts building performance and sustainability

Buildings account for about 40% of global energy consumption, illustrating why EUI has become more important as a benchmark to compare buildings.

It’s crucial for:

  • Identifying energy inefficiencies in building systems
  • Reducing operational costs with energy savings
  • Lowering energy consumption and minimising environmental damage
  • Attracting sustainability-focused tenants and investors
  • Meeting regulatory requirements for energy efficiency

Understanding the impact of EUI on building performance and sustainability helps your business make data-driven and well-informed business decisions about your site. From finding out how to improve its efficiency to saving money in the long run, EUI can be a game changer for your business.

Leveraging smart building solutions to improve EUI

Integrating smart building solutions can help you dramatically lower EUI. In addition to reducing energy usage and related costs, they improve occupant comfort and your building’s efficiency.

Here’s how they can help:

  • Building Automation Systems (BAS) integrated with HVAC and lighting control systems can reduce electricity consumption
  • Smart HVAC systems based on occupancy and zonal use can also reduce electricity usage
  • Intelligent lighting control can significantly reduce lighting-related energy consumption

Utilising these digital solutions helps you monitor usage, identify areas for improvement, and maximise your building’s efficiency.

Steps for reducing EUI with energy efficient solutions

Let’s explore some practical ways to use energy-efficient and smart building solutions to reduce your EUI:

Implement smart HVAC systems

Using artificial intelligence (AI) and the Internet of Things (IoT) to control and monitor systems precisely can help reduce EUI. In addition, smart HVAC systems autonomously adjust temperatures based on your building’s occupancy and external climatic conditions.

Install intelligent lighting

Intelligent lighting systems have several functions that can help reduce EUI. Autonomous dimming, daylighting, and occupancy-based switching on and off can reduce unnecessary energy usage. Meanwhile, implementing time scheduling for when your building is occupied optimises energy usage.

Integrate building automation systems

Connect your HVAC, lighting, and other building systems to give yourself overall control of the climate. Use data outputs to monitor your system’s efficiency and effectiveness and look for potential issues.

Analyse energy use

Tracking your building’s EUI regularly helps you identify seasonal trends and potential anomalies. This enables you to benchmark your building’s base performance and identify areas for possible savings and economies.EducationTracking your building’s EUI regularly helps you identify seasonal trends and potential anomalies. This enables you to benchmark your building’s base performance and identify areas for possible savings and economies.

Education

Take time to educate your building’s occupants by promoting energy-saving behaviours. Share your EUI goals and progress with occupants, and consider incentivising them to participate in improving your building’s sustainability.

Switch to renewable sources

Exploring renewable sources of source energy can significantly boost your EUI. Consider on-site solar or wind power generation. You may be able to sell unused energy back to the National Grid to help increase profitability and help others with environmental benefits.

Retrofit buildings

Retrofitting existing buildings to help improve your EUI is straightforward. Install wireless IAQ sensors and integrate them with your existing BMS. In addition, upgrades to energy-efficient equipment and appliances should be made where possible to improve sustainability.

For example, the UKGBC report ‘Building the Case for Net Zero’ illustrates that the retrofit classification has been calculated based on the mean impact of EUI and the cost per unit gross internal area (GIA).

As a result, the average value of an SDCV solution installation is between £8 and £13/m² with an energy saving of between £4 and £7/m². As a result, the overall mean impact on EUI is 15 to 20%.

The final word

As the world moves towards net zero, EUI will grow in importance, shaping future commercial buildings. In addition to providing a standard metric to compare energy efficiency, it helps owners, managers, and auditors find economies and improvements.

However, to maximise your building’s EUI, seeing it as more than a number is essential. Your EUI is a roadmap to sustainability, helping you improve your working environment, save money, and boost your building’s ratings.

Rensair’s SDCV solutions place us as a light retrofit company on cost with a deep retrofit mean impact on EUI compared to other providers on the market. This makes us a highly attractive retrofit partner for leading tenants such as Salesforce.

To learn more about how our energy-saving solutions can help you and your business combat climate change and save money, contact us today and begin your journey to commercial sustainability.

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