SECURITY In modern systems,


energy management now depends on connectivity. BMS platforms aggregate data about humidity, CO2 levels, power consumption, and equipment status, and issue commands back to field devices. Many systems now incorporate cloud-based analytics platforms that enable remote monitoring and predictive maintenance. This architecture


creates multiple potential entry points. Internet- of-Things (IoT) sensors, often manufactured by third parties with varying


Power-intensive hospital equipment.


Great Grid Upgrade will fundamentally alter how hospitals receive and manage power. These changes promise sustainability, but they also introduce intermittency and complexity that legacy systems were never designed to handle. Digital transformation ties these threads together. Smart


energy management systems promise to square the circle: delivering both the reliability an ageing population requires and the efficiency that sustainability demands. Building management systems can now predict equipment failures, optimise energy use by zone, integrate renewable generation, and provide facilities managers with granular visibility across entire estates. Royal Preston Hospital in Lancashire demonstrates this potential. The hospital serves over 1.2 million patients annually and has gradually replaced legacy infrastructure with a unified, open control system managing ventilation, boiler plants, heating, lighting, and temperature by zone, while occupancy sensors reduce waste in empty rooms. These seemingly modest interventions deliver profound cumulative benefits. But digital convergence creates risks. As hospitals connect previously isolated systems, they create pathways that could cascade across multiple critical functions.


BMS and the new attack surface Old hospital electrical systems were largely ‘air-gapped’, meaning they were physically isolated from data networks. A boiler controller in the basement had no connection to patient records systems. Circuit breakers were operated mechanically. HVAC systems ran on closed-loop controls. Installing these was not a ‘security strategy’ – just how the technology worked at the time. But in a way, it provided inherent protection.


security standards, can be compromised. Communication protocols like Modbus, BACnet, and KNX, if not regularly updated to the latest version, may lack robust encryption. Healthcare environments are particularly bad for this. Many hospitals operate with mixed-generation infrastructure where new smart systems interface with decades-old equipment. IT security budgets still prioritise clinical systems and patient data protection, with BMS receiving less attention. Estates departments may lack cybersecurity expertise, while IT departments may not fully understand operational technology risks. And the pace of digital transformation often outstrips the capacity to implement proper security governance. The consequences of these vulnerabilities have become apparent in recent years. In a ransomware attack in June 2020, University of California’s San Francisco campus was forced to pay $1.14m to recover the research data of dozens of faculties. A few years later, neighbouring health centre Scripps Health was almost entirely shut down for five weeks due to a separate attack. In June 2024, organised cybercriminals raided the Synnovis blood pathology laboratory in London, stealing sensitive patient data. That even led to the death of a patient who had to wait too long to get a test result. While these attacks focused on information theft and


destruction, they demonstrated healthcare’s attractiveness as a target and the sophistication of threats facing the sector. Building management systems, if poorly secured, represent an even more concerning vulnerability – one that could enable attackers to directly cause physical harm.


So, what could happen?


n Scenario one: environmental manipulation


Digital convergence creates risks. As hospitals connect previously isolated systems, they create pathways that could cascade across multiple critical functions.


58 Health Estate Journal April 2026


An attacker gains access to a hospital’s building management system through a compromised IoT sensor. During an extended summer heat wave, the attacker disables or misconfigures HVAC controls in specific wards. Temperature alarms are suppressed or delayed. By


the time staff notice patients exhibiting signs of heat stress, multiple elderly individuals require emergency intervention. The hospital must evacuate affected wards, putting additional strain on already stretched resources.


AdobeStock / Gorodenkoff


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