Why retrofits represent a route to resilience
21 November 2025
How do data centres respond to pressure to increase performance without increasing their footprint, emissions or energy usage? Steve Clifford, director of data centres at EMCOR UK, argues that for many the answer is not new build, but retrofit.
In the race to improve energy efficiency across our built environment, data centres present both a challenge and an opportunity. These mission-critical facilities are under pressure caused by rising demand, limited grid access, and tightening carbon goals. The infrastructure required to support modern workloads, including AI, edge computing, and high-density storage, is expanding fast, but the ability to power, cool and control it sustainably is not keeping pace.
Retrofitting offers a practical response. It allows organisations to significantly improve energy performance while retaining core infrastructure, while avoiding the embodied carbon and disruption of new construction. Embodied emissions from materials, transport and build phases are often overlooked in energy strategy yet increasingly form part of procurement frameworks and corporate ESG reporting.
The business case is compelling. Retrofit programmes can reduce capital expenditure by up to 40% and deliver value around 30% faster than new build. The operational savings are equally important. Replacing ageing cooling systems with high-efficiency alternatives, improving airflow, and integrating energy controls can reduce energy consumption by up to 25%. These interventions often bring secondary benefits: lower maintenance costs, improved resilience, and easier alignment with ISO 50001, ESOS, and Scope 1 and 2 emissions reporting.
Pressure points
Organisations typically consider retrofit when several pressure points converge: rising energy bills, frequent failures of ageing mechanical and electrical systems, or a lack of space and power capacity to accommodate new technologies. In some cases, it’s the result of increasing scrutiny over emissions reporting. In others, it stems from the realisation that expansion is simply not viable, either due to grid limitations or prohibitive planning requirements.
Today’s retrofit programmes are far more strategic than reactive. They are comprehensive initiatives designed to modernise plant, optimise building performance, and prepare facilities for long-term operational needs. Projects often involve replacing legacy switchgear and UPS systems with high-efficiency equipment, upgrading cooling plant, and integrating intelligent controls that improve airflow, monitor energy usage, and reduce waste.
Crucially, these improvements can often be made without expanding the physical footprint. In one recent project, we integrated a new 380V DC power system and hot aisle containment to achieve over 96% conversion efficiency and increased cabinet density, all while keeping the data centre fully operational.
In another project, we transformed a disused call centre into a high-performance fibre hub within 12 weeks, despite tight energy constraints. The key to success was phased planning, off-site fabrication, and detailed modelling of space and risk.
Planning ahead
Retrofitting a data centre is not without complexity. Uptime must be preserved. Risks must be controlled. And all works must be delivered in live, critical environments. That makes early planning essential.
Modern retrofit delivery relies on a combination of digital modelling, laser scanning, temporary cooling and power systems, and phased installation. Off-site fabrication reduces time on site and minimises disruption.
Integrated systems testing ensures that every stage is validated under real operational conditions. These are not simply construction projects; they are collaborative engineering programmes, where energy strategy, resilience planning and lifecycle performance converge.
For energy professionals, retrofit is no longer a reactive intervention, but a route to resilience. It enables organisations to increase uptime, reduce energy intensity, and support carbon commitments using infrastructure they already own. With the right roadmap, retrofits can be phased over time and aligned with capital planning and reporting cycles. They support asset optimisation while enabling faster alignment with policy, compliance, and corporate sustainability frameworks.
