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Why EUI is important for low-carbon buildings

Kris Swiderski explains the emerging role of EUI in building efficiency and the impact of Service & Maintenance on lowering this increasingly important measure.

In the landscape of building efficiency and sustainability, the quest for 'Net Zero' buildings has encountered challenges, mainly due to the absence of clear definitions and measurable standards. If we don’t have a map, how can we get there?

But the horizon is brightening with the anticipated launch of a UK Net Zero Carbon Standard.

This development is generating considerable interest within the industry as it sets out to provide clear descriptions and tangible characteristics of a truly Net Zero Carbon building.

This shift towards more accurate and realistic energy measurement is a crucial step forward

Kris Swiderski Hub Kris Swiderski Head of Service and Maintenance

Measuring how you use energy

This new standard's central component is the Energy Use Intensity (EUI) concept. It’s important because it provides a measurement of a building's energy efficiency that is more accurate (and useful) than Energy Performance Certificates (EPCs), which are largely theoretical.

EUI measures the actual energy consumption of a building per square meter, encompassing both regulated and unregulated energy use.

This shift towards more accurate and realistic energy measurement is a crucial step forward in assessing and managing a building's carbon footprint.

Understanding EUI is vital, not just for new constructions but also for existing building stock. In the past, operational carbon calculations often overlooked indirect operational emissions.

These emissions, often from electricity produced by fossil fuels, contribute significantly to a building's environmental impact. In the UK, it's estimated that 71% of the built environment emissions are indirect operational emissions, underlining the urgent need for more effective energy management strategies.

The performance gap

The challenge, historically, has been our reliance on predictive models like EPCs.

While they give some indication of buildings’ relative energy performance, they don't fully account for actual energy usage, particularly unregulated energy.

This includes energy consumed by appliances like office microwaves, server rooms, and plug loads, which can constitute up to 50% of a building's total energy consumption in some instances.

This theoretical assessment of building energy use resulted in what CIBSE has referred to as the ‘performance gap’ – buildings don’t perform as intended.

Disconnect between predicted and actual

The Better Buildings Partnership (BBP) further underscored the limitations of EPC ratings in its 2020 survey. In 1,100 commercial properties, BBP research revealed that buildings with high EPC ratings (A and B) often consumed more energy than those with lower ratings (C, D, or E).

This disconnect between predicted and actual energy use has propelled the industry towards more reliable metrics, such as EUI.

EUI encompasses all energy use within a building, regulated and unregulated, measured at the meter against the building floor area. Leading organisations, including CIBSE and the UK Green Building Council, increasingly recommend its adoption.

The Council's Whole Life Carbon Roadmap advocates for EUI as a compliance approach within Building Regulations, urging a shift from hypothetical models to tangible, outcome-led performance metrics.

This is where the role of a proficient Service & Maintenance partner becomes indispensable. At Mitsubishi Electric, we have developed an in-depth understanding of these evolving standards and measures. We aim to work with building managers to help them through the complexities of reducing EUI.

By ensuring that building services equipment such as chillers operate at peak efficiency, together, we can play a pivotal role in helping buildings meet new and more accurate standards.

EUI is gaining momentum

In summary, as we edge closer to the implementation of a Net Zero Carbon Standard, the focus on EUI as a measure of a building's energy efficiency is gaining momentum.

It represents a more accurate, comprehensive approach to understanding and reducing a building's carbon footprint.

For building managers, working with knowledgeable Service & Maintenance partners is a strategic step towards achieving lower EUI and, ultimately, contributing to the delivery and operation of Net Zero buildings.

Kris Swiderski is Head of Service and Maintenance