RETROFITTING
considerations influence how digital technologies, including those supporting the built environment, are deployed and managed over time. The NHS’s Digital Technology Assessment Criteria (DTAC)11
reflect an
industry-wide expectation that security assurance is now a baseline requirement, not an optional feature, and that expectation is extending, by necessity, from clinical devices to building infrastructure.12
What a secure retrofit looks like in practice n Replacing or segmenting legacy protocols where they cannot support modern security controls.
n Reducing unmanaged remote access and moving toward controlled, authenticated, monitored connectivity.
n Improving asset visibility and documentation of OT architecture across estates and IT teams.
n Applying security-by-design principles to all new controllers, gateways, and supervisory platforms.
n Aligning upgrade programmes with NHS cybersecurity expectations and evolving OT maturity frameworks.
Once estate managers can demonstrate where energy is being lost, the business case for retrofitting becomes far stronger.
to platforms that surface exceptions, not just readings.7 This shift from reactive to proactive management is one of the most significant operational improvements a Trust can make, and it does not require replacing major plant to deliver results.8 This is why a ‘controls-first’ approach has become so compelling in healthcare settings. By targeting the supervisory layer and upgrading controllers and sensors during planned works, estates teams can capture significant energy and carbon savings without invasive intervention into clinical spaces.9
In many buildings, it
is also possible to reuse elements of existing cabling infrastructure, including legacy building automation wiring, as the industry moves towards long reach Ethernet technologies and IP native control architectures. This allows buildings to move from legacy set ups with increased costs to modern, interoperable networks without opening ceilings, replacing cabling or estates being unable to use the premises during works. The result is significantly lower project costs. The adoption of open protocols and interoperable
platforms helps mitigate reliance on proprietary vendor ecosystems that may restrict upgrade pathways and contribute to higher long-term costs. This shift provides healthcare estates access to a broader ecosystem of solutions, enabling greater choice, competitive procurement, and the integration of best-in-class technologies. It also allows them to leverage advanced analytics and energy optimisation tools while positioning their assets to adopt emerging innovations, such as cloud services and AI-driven automation. The practical benefit in live clinical environments is considerable. Reduced rewiring means less disruption.10 Staged rollouts can be aligned with ward refurbishments, departmental moves, and lifecycle replacement schedules, fitting around clinical priorities rather than competing with them.
Strengthening cybersecurity As commercial buildings become more connected, it is increasingly important that the controllers operating them are secure and can be kept up to date with the latest firmware and software. Healthcare operates within a highly regulated and availability critical environment, shaped by factors such as extended device lifecycles, defined maintenance and update windows, and the need to sustain continuous clinical operations. These
94 Health Estate Journal September 2026
A fast route to sustainability compliance Retrofitting is an effective way to meet sustainability and carbon reduction goals,13
allowing building owners to
replace outdated control systems with high efficiency, interoperable alternatives that help to reduce energy consumption, lower emissions, and support compliance with evolving UK regulations. Crucially, retrofit-ready technologies enable faster, low disruption installation through modular components and cable reuse approaches, minimising downtime and inconvenience for buildings that remain fully occupied or operate on tight schedules.14 The NHS’s commitment to Net Zero – 2040 for direct emissions, 2045 for those it can influence – is not aspirational language. It is embedded in healthcare governance and estate planning, with Trusts expected to move beyond high-level pledges and deliver measurable, auditable progress.15
For most NHS organisations, the
existing estate is where the largest gains are available, and where the pressure is most immediate. Deep decarbonisation, plant replacement, heat pump
transitions, and fabric improvements require significant capital and lead time. Controls and monitoring upgrades do not. Case studies published in the CIBSE Journal demonstrate that BMS optimisation, combined with improved data visibility, can deliver energy reductions of up to 28 per cent without major capital works.16
For
healthcare buildings, where outpatient clinics, meeting rooms, admin areas, and teaching spaces are frequently unoccupied or partially used, smarter scheduling and demand-responsive control can be particularly powerful: matching ventilation, heating, and cooling usage to real occupancy patterns rather than fixed assumptions. Critically, these interventions also generate the data
infrastructure needed to make the case for larger capital investment. When Trusts can demonstrate precisely where energy is being lost, how systems are performing against design intent, and what the carbon impact of specific interventions would be, the business case for deeper retrofit becomes far easier to justify.
Working together for retrofit success Energy and carbon are not the only story. In healthcare settings, the built environment has a direct bearing on clinical outcomes,17
staff wellbeing, and infection control.
Ventilation is not merely a comfort consideration, it is clinical infrastructure, subject to detailed national guidance
AdobeStock / Katawaredoki
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