Case study · Hospital campus
Keeping cirical care warm while cutting carbon risk.
How Kingston Hospital is replacing an ageing steam system with low temperature heat pumps — cutting carbon, improving air quality and keeping care running without interruption.
What was happening
A steam based heating system running day and night, responsible for 58 percent of site emissions and increasingly misaligned with a modern healthcare environment.
What was needed
A credible path to low carbon heat that could be delivered in a live hospital without disrupting patient care or clinical operations.
What we unlocked
A campus wide transformation from steam to low temperature hot water, with heat pumps replacing gas and a phased route to net zero heat.
A hospital where heat is not optional
Hospitals never sleep. Neither do their heating systems.
At Kingston Hospital, heat underpins everything — patient comfort, infection control, clinical resilience and staff wellbeing. But the system delivering it was built for a different era.
A central steam network, powered by gas fired boilers, was operating continuously across the estate. It was energy intensive, maintenance heavy and responsible for 58 percent of the site’s building related carbon emissions.
With the NHS committed to net zero direct emissions by 2040 and an interim target of 80 percent reduction by 2032, the hospital needed more than incremental efficiency. It needed a fundamental rethink of how heat was produced and distributed.
The biggest carbon lever was hiding in plain sight
Detailed analysis confirmed what intuition suggested: decarbonising heat would deliver the single biggest carbon reduction opportunity on site.
But replacing steam in a live hospital is not a like for like swap. Steam systems are unforgiving. They mask inefficiency, demand high temperatures and leave little room for modern low carbon technologies.
Extensive site surveys revealed an opportunity to do something bolder — to move the entire campus away from steam and towards a low temperature hot water system that could unlock efficient heat pumps, better control and long term flexibility.
The challenge was not technical possibility. It was sequencing, safety and absolute continuity of care.
Designing a whole system transformation, not a bolt on solution
Working as lead designer for site wide heat decarbonisation, we supported the client through BSRIA Stage 2 concept design and into detailed delivery.
We surveyed the entire estate and built a hydraulic digital twin of the hospital’s heating system. This allowed us to model real world behaviour, test decarbonisation scenarios and understand how changes in one part of the system would ripple across the campus.
Alongside clinical, estates and technical teams, we developed a phased strategy to remove steam distribution entirely and replace central gas boilers with electric heat pumps powered by low carbon electricity.
Every switchover was planned around operational reality — wards, theatres and critical services remaining fully supported at all times. This was design shaped by lived hospital rhythms, not idealised assumptions.
From ageing infrastructure to a future ready heat backbone
The resulting design sets Kingston Hospital on a clear path to cutting heat related carbon emissions by more than half, while significantly improving local air quality across the site.
Moving to low temperature hot water reduces losses, improves controllability and creates a platform for future electrification and flexibility as the grid continues to decarbonise.
Crucially, the project demonstrates that deep decarbonisation is possible in complex healthcare environments without compromising safety, resilience or care.
Our support continues as the project progresses through RIBA Stage 4 detailed design and into delivery.
Because fossil fuels should not be part of the cure
Healthcare exists to protect and improve human health. The systems that support it should do the same now and for generations to come.
Clean heat in hospitals is not just about carbon targets. It is about air quality for patients, safer working environments for staff and resilient infrastructure that can adapt over time.
Kingston Hospital shows what becomes possible when heat is treated as a core part of care itself — designed with the same thought, responsibility and long term view as the services it supports.