BEMS: How smart building controls cut energy use by up to 50%

Improving the operational performance of buildings is one of the fastest and most cost-effective ways to reduce energy consumption and carbon emissions across the built environment. As buildings become more electrified, connected and data-driven, advanced building controls and Building Energy Management Systems (BEMS) are emerging as critical technologies in delivering smarter, lower-carbon buildings.

BEMS integrate and coordinate building services including HVAC, lighting and energy metering, enabling systems to respond dynamically to occupancy patterns, environmental conditions and energy demand. By ensuring equipment operates only when and where it is needed, building controls reduce wasted energy while maintaining comfortable and productive indoor environments.

The energy and carbon savings opportunity

Research published in the BCIA white paper Comfort, Efficiency and Health: The Untapped Potential of Building Energy Management Systems highlights the scale of the opportunity. The analysis shows that advanced building controls can deliver energy savings of between 20% and 50%, depending on building type and system integration.

When deployed at scale across offices, education buildings and hospitals, advanced BEMS could deliver 15 million tonnes of CO₂e emissions savings between 2026 and 2035, equating to an annual reduction of around 7.4% of emissions from UK commercial and public sector buildings.

Integrating building systems for smarter performance

Unlike many decarbonisation measures that target individual building systems, BEMS provide a platform for integrating and optimising multiple services simultaneously. Advanced systems coordinate heating, cooling, ventilation, lighting and energy monitoring through data analytics and automated control strategies that continuously optimise performance.

This enables building operators and facilities managers to reduce energy demand, minimise operational waste and improve overall system efficiency without necessarily requiring major plant upgrades.

The white paper analysis also highlights the financial case for upgrading controls. In a typical 1,000m² office building, moving from a standard control system to an advanced Class A BEMS can deliver 105 tonnes of CO₂e savings over ten years, while achieving a payback period of around four years through energy and operational savings.

From a carbon abatement perspective, building controls also compare favourably with other low-carbon technologies. The research shows that advanced BEMS can deliver carbon reductions at a cost of £224 per tonne of CO₂e abated, making them one of the most economically efficient measures available for improving building performance.

Smart controls must also work in practice

As buildings become increasingly digital and connected, the role of building controls continues to expand. However, ensuring systems remain usable and effective in real-world operation remains essential.

Ron Purcell, Vice President of the Building Controls Industry Association and Product Manager at Siemens, believes the industry must focus on delivering systems that combine intelligence with usability.

“Building controls are fundamental to delivering energy efficient buildings that also support the wellbeing of the people who use them. As buildings become more connected through digital technologies and IoT, it’s essential that control systems are intelligent enough to manage increasingly complex environments while remaining intuitive for building operators.”

With around 80% of the buildings that will exist in 2050 already built, improving how existing buildings operate will be essential if the UK is to achieve its net zero targets.

Advanced building controls provide a practical route to achieving this. By improving how building systems operate in real time, BEMS can reduce energy consumption, cut carbon emissions and improve indoor environmental quality without the need for extensive structural interventions.

As the smart buildings agenda continues to evolve, building controls will play an increasingly central role in improving the performance of the UK’s building stock, ensuring buildings are not only intelligent, but also efficient, resilient and sustainable.