Architects at the heart of NHS decarbonisation

The National Health Service (NHS) is the UK’s largest public sector emitter of carbon emissions, a statistic that is particularly concerning given its crucial role in the health and wellbeing of millions of people. The NHS operates an extensive and ageing estate, which is not only a source of significant carbon emissions, but also increasingly a source of financial pressure due to rising energy costs, inefficiencies in building design, and the ongoing challenges of maintaining older buildings. In an era of climate change, the push for decarbonisation is more urgent than ever, and the healthcare sector is under increasing pressure to reduce its environmental impact.

NHS ‘in a unique position’

While global climate change targets set an imperative for decarbonisation, the NHS, with its vast estate, is in a unique position to reduce not only carbon emissions, but also to benefit financially from this transformation. The drive for carbon reduction, commonly referred to as ‘Net Zero Carbon’ (NZC), offers a significant opportunity to lower long-term energy costs and operational expenses (the NHS Net Zero Building Standard was published on 22 February 20231). Alongside this is The Net Zero Commitment, a voluntary pledge within the UK’s private healthcare sector, with the aim of achieving Net Zero emissions by 2035, and a Net Zero supply chain by 2045. This initiative builds on the NHS’s target of achieving Net Zero by 2040, and supports the UK government’s commitment to net zero by 2050.

Architects, with their expertise in both the design and operational performance of healthcare environments, are key players in this transition. They are well positioned to guide NHS Trusts in achieving NZC through both new-builds and retrofits, ensuring that carbon reduction strategies are seamlessly integrated into the built environment, while also delivering substantial cost savings over time.

This article explores how architects can assist NHS Trusts and other healthcare institutions in developing and implementing NZC strategies, how their expertise can drive cost reductions, and the role of external partnerships, including organisations like Salix, which provide funding for energy efficiency projects.

Salix and funding mechanisms: unlocking the opportunity

While the technical solutions for achieving Net Zero Carbon are available, one major barrier for NHS Trusts is financing. The upfront capital required for energy-efficient upgrades can be significant, and many Trusts face financial constraints. However, Salix Finance, a non-departmental public body, plays a critical role in bridging this gap — by providing interest-free loans to public sector organisations for energy-saving projects.

Salix’s financing model is particularly beneficial for the NHS, as the loans are repaid through the energy savings generated by the upgrades. This allows NHS Trusts to make improvements without the need for significant upfront investment. For example, Salix has supported Trusts in funding projects such as LED lighting upgrades, heating system improvements, and renewable energy installations.

According to a recent study by Gardiner & Theobald, NHS Trusts could save up to £2.8 bn annually over a 15-year period by adopting NZC strategies.² Many of these projects offer a 4-5 year payback period, making them financially viable and sustainable in the long term.

In the private sector, green finance models are evolving too, from corporate sustainability-linked bonds to private PPAs (Power Purchase Agreements) and on-site renewable leasing — allowing providers to transition without upfront capital costs. Private healthcare facilities do have the possibility to find financial funding through Government grants for energy reduction projects, and institutional/private investment.

Rethinking the role of architects: from designers to strategic advisors

In the past, architects were primarily seen as designers tasked with creating aesthetically pleasing and functional buildings. Today, however, architects play a much broader, more strategic role, particularly within healthcare and public sector institutions like the NHS. Architects specialising in sustainable design and Net Zero Carbon strategies have become invaluable advisors in the healthcare sector, offering critical insights into how carbon emissions can be reduced, energy efficiency can be improved, and operational costs can be lowered over the long term.

Cagni Williams Associates (CWA) embraces wholeheartedly this expanded role. The firm, alongside Cagni Williams Energy (CWE), offers a full suite of services designed to make healthcare institution buildings more sustainable and energy-efficient. These services include carbon impact analysis at the early design stage, whole-life energy modelling, and long-term estate decarbonisation planning. By collaborating with engineers, cost consultants, clinical leaders, and Estates teams, we ensure that sustainability is embedded into the design and planning process from the outset.

Architects — due to their systems thinking approach, can integrate multiple factors — such as building performance, energy use, patient needs, and operational efficiencies — into the design process. Their expertise in coordinating complex systems is critical in achieving high-level sustainability goals, and ensuring that these goals are met in a practical, financially viable way. The result is a significant reduction in carbon footprint, lower energy costs, and improved operational efficiencies that benefit the NHS Trust, private healthcare institutions, and the local community.

The energy-cost equation: why Net Zero makes financial sense

The rising costs of energy, exacerbated by global events and market volatility, present a significant financial burden on NHS Trusts. The NHS is a major energy consumer, and its energy usage is projected to rise as the demand for healthcare services continues to increase. This makes it even more imperative to focus on reducing energy consumption and moving towards Net Zero Carbon (NZC) strategies.

One of the most compelling arguments for NZC in the NHS is the financial impact, though private healthcare suffers from the same energy costs. Through energy-efficient design and the integration of renewable energy sources, Trusts can dramatically lower their utility bills over time. By focusing on passive design strategies — such as improved insulation, natural ventilation, and solar shading, etc, architects can design buildings that are inherently more energy-efficient. Additionally, by incorporating active systems like heat pumps, solar photovoltaic (PV) panels, and energy storage solutions, architects can help Trusts reduce their carbon output while simultaneously lowering energy expenditure.

Benefits especially evident in retrofits

In retrofitting existing facilities the financial benefits of adopting NZC strategies are particularly evident. Many healthcare buildings, particularly older ones, suffer from outdated, inefficient energy systems. Retrofitting these buildings can reduce energy use by 30-50%, which translates into substantial savings in both energy costs and maintenance over time. In a period of tight budgets, these savings are critical in enabling all healthcare providers to achieve both their sustainability goals and their financial objectives.

For new healthcare buildings, the opportunity to achieve NZC performance is greatest at the design stage. Architects play a critical role here, providing early strategic advice on how the building can be designed to meet Net Zero Carbon goals. By establishing NZC targets from the outset, and ensuring that these are integrated into every aspect of the design, architects can help Trusts avoid the costs and challenges of future retrofitting.

One key strategy is a fabric-first approach, which focuses on ensuring that the building’s envelope performs efficiently, reducing heating and cooling loads. Passive solar design is another critical consideration, with architects using building orientation and glazing to maximise natural light and heat gain, thus reducing the need for artificial lighting and heating. Furthermore, architects can design for thermal mass and insulation, leveraging the building’s structure and airtightness to improve energy performance.

In addition, architects can plan for integrated renewable energy systems, such as solar panels, air or ground source heat pumps, and battery storage, which can significantly reduce the building’s reliance on fossil fuels and contribute to achieving Net Zero Carbon status. By designing healthcare buildings with these systems in mind, architects ensure that these facilities are not only energy-efficient, but also resilient, and capable of adapting to the demands of future healthcare needs.

• Design Toolkit: Future-Ready, Net Zero Carbon hospitals

Our design toolkit focuses on practical, scalable interventions that balance architectural quality with deep environmental performance:

Passive Design Fundamentals include:

• Design decisions made early on dramatically reduce reliance on mechanical systems later.
• Orientation: Aligning clinical and patient areas to maximise natural daylight, reducing reliance on artificial lighting and heating.
• Thermal mass: Incorporating exposed structural elements such as concrete floor slabs and internal walls to help stabilise internal temperatures.
• Natural ventilation: Designing operable windows and cross-ventilation strategies in non-clinical zones to reduce mechanical cooling needs.
• Solar control: Using fixed and operable shading (brise soleil, vertical fins) to prevent overheating while preserving daylight.
• High-Performance Envelope
• A thermally efficient building fabric is fundamental.
• Vacuum Insulated Glazing (VIG): Achieving U-values as low as 0.3 W/m²K, this lightweight glazing solution is especially valuable for retrofitting older façades, where weight or depth constraints preclude triple glazing.
• Airtightness: Designing to meet or exceed Passivhaus benchmarks reduces uncontrolled heat loss and improves system efficiency.
• Insulation and rainscreen systems: Aesthetically flexible and thermally robust, enabling performance uplift while respecting existing architectural identity.

Ground source heat pumps

We are fans of solutions like ground source heat pumps (GSHPs), which offer compelling advantages. They use compact underground pipework to extract and deliver efficiently heat and even more cooling, with minimal maintenance requirements — an important distinction compared with air source heat pumps (ASHPs), which rely on large external fans and require more frequent servicing. Additionally, GSHPs demand less spatial allocation, a crucial benefit for constrained new-build sites, and have double the coefficient of performance of ASHPs. Mechanical ventilation with heat recovery (MVHR) systems further support energy conservation. By continuously supplying filtered fresh air while recovering heat from exhaust air, MVHR reduces the need for additional heating or cooling, and improves indoor air quality — key in both clinical and recovery environments. Advancements in solar PV technology have significantly increased efficiency, making it possible — particularly in low-consumption healthcare buildings — to approach or achieve near-grid independence, especially combined with other systems. This not only reduces operational carbon, but also enhances long-term energy resilience. Reducing overall energy consumption and decarbonising must be the primary focus, among wider sustainability measures.

These components form the bedrock of any Net Zero strategy, whether applied to a new hospital, or layered into a multi-phase retrofit masterplan. They allow the mechanical engineering side to be much more efficient, while tackling the subject from all sides opens up better solutions as the energy demand lowers. This is the reason why the collaboration between the architect and the specialist engineers needs to be very close from the project’s beginning.

While new-builds are an ideal opportunity to embed NZC strategies from the start, the bulk of the NHS estate is already in existence. In fact, over 80% of the NHS estate projected to be in use by 2040 is already standing. This means that achieving Net Zero Carbon targets will depend largely on how these existing buildings are retrofitted.

Retrofitting is a powerful tool for improving the energy performance of existing healthcare facilities. The benefits of retrofitting are not just environmental, but also financial. By upgrading building insulation, replacing outdated HVAC systems, and installing renewable energy technologies, NHS Trusts can achieve significant energy savings. Architects play a key role in identifying which retrofit measures will deliver the most cost-effective results, taking into account the building’s age, energy use, and condition.

Priority criteria

CWA’s approach to retrofitting involves prioritising projects based on energy consumption, patient volume, and structural integrity. By focusing on high-impact upgrades that deliver the greatest savings, architects can help NHS Trusts reduce their energy bills and maintenance costs, all while improving the environmental performance of the estate, which can include:

• LED lighting upgrades.
• Heating and ventilation refurbishments.
• Solar photovoltaic (PV) installations.
• BMS optimisations and insulation improvements.
• GSHP systems.
• Vacuum-insulated glazing.

Achieving Net Zero Carbon in NHS and other healthcare buildings goes beyond design alone; it also requires an integrated energy strategy that ensures the building’s energy systems are as efficient as possible. For this reason, CWA works closely with its sister consultancy, CWE (HEJ — April 2025), which specialises in providing energy strategies which can be tailored specifically to healthcare estates. CWE’s services were set up in order to advise healthcare institutions on:

• Battery storage and microgrid systems.
• Smart demand management for energy flexibility.
• Ambient loop heat networks, which provide low-carbon heating to multiple buildings.
• Planning renewable energy installations, including solar arrays, electric vehicle (EV) charging stations, and microgrids.
• Energy storage and demand flexibility — by integrating architectural and energy strategies, offering all clients a comprehensive approach to reducing carbon emissions and lowering energy costs.
• Ground source heat pumps (GSHPs) offer a highly efficient, low-carbon solution for heating and cooling — especially valuable at hospitals and other healthcare facilities, where energy demand is high, and operational continuity critical. A GSHP extracts heat from the ground using buried pipework (vertical boreholes), and uses a heat exchanger to transfer that energy to a building’s heating system. Importantly for healthcare, it can also reverse this process for cooling. The six main advantages for healthcare providers are:
• High Energy Efficiency.
• Support of Net Zero Goals.
• Stable and low-maintenance operation.
• Heating and cooling in one system to maintain stable and comfortable indoor environments.
• Quiet and low-impact.
• Eligibility for funding for the public sector.

For healthcare facilities, ground source heat pumps offer a resilient, efficient, and future-proof heating and cooling solution.

As an example, CWE is currently discussing with several NHS Foundation Trust hospitals in London how to decarbonise both their existing estate and a new 15,000 m² building on one of the Trusts’ Chelsea campus by using an ambient loop system and GSHP systems. Through the use of GSHPs, the hospital can reduce electricity costs, lower maintenance expenses, and improve its local environmental impact. Additionally, the ambient loop system will support a Community Benefit Fund, which will reinvest funds into the local area, supporting the community, and enhancing the social value of the project. CWE’s consulting engineers, Genius Energy, have already been involved in projects for several UK healthcare Trust sites, including: Cherry Knowle Hospital, Sunderland; North Middlesex Hospital, London; King’s Mill Hospital in Nottinghamshire; Papworth Hospital in Cambridge; Whipps Cross University Hospital, London, and St Catherine’s Hospital, Wirral, where similar heat pump systems have been applied.

Healthcare estates and sustainable communities

The role of architects in the decarbonisation of healthcare estates extends beyond individual buildings, both new and existing. Architects are increasingly advising clients on how entire healthcare campuses and surrounding areas can be designed to be more sustainable and community-friendly. Through urban design and estate-wide masterplanning, architects help integrate healthcare facilities into broader strategies for low-carbon transport, public access, and community engagement.

We recommend that our clients aim for walkable hospital sites with low-traffic areas, enhancing green spaces, and improving connections to public transport, cycling routes, and pedestrian infrastructure. By positioning healthcare buildings as anchors for sustainability within their communities, architects can help improve public health and resilience to climate risks such as flooding and heatwaves.

Masterplanning

Masterplans by CWA increasingly include:

• Green corridors and biodiverse landscaping.
• Low-traffic or pedestrian priority zones.
• Improved cycle and public transport links.
• Flood resilience and overheating mitigation.

One of the key challenges in achieving Net Zero Carbon within the NHS is overcoming the fragmented nature of policy implementation, siloed operations, and the lack of continuity across projects. NZC requires whole-systems thinking.

Achieving NZC isn’t just about efficient equipment — it’s about integrating architecture, systems, and behaviour. Architects shape the building form, orientation, materials, daylight access, and natural ventilation — all of which have profound long-term energy implications. Early design decisions on new-builds can either drastically reduce or lock in high energy use for the building’s lifetime.

As leaders of the project vision, architects ensure:

• Renewable integration is architectural, not bolt-on.
• Embodied carbon is accounted for in material choices.
• Circular economy principles are embedded in detailing.
• Post-occupancy feedback loops improve future performance.

Leading on embodied carbon reductions

Even with retrofit situations, architects with energy expertise can lead on embodied carbon reductions through smart material choices, coordinate renewable energy integration (e.g. PV panel placement), and collaborate across disciplines for Net Zero-ready design. With their holistic understanding of design, systems integration, and project management, architects are thus ideally placed to bridge these gaps. By collaborating with clinical leads, Estates managers, engineers, and other stakeholders, architects ensure that sustainability and operational efficiency are balanced. While engineers are crucial for detailed system design, an architect with energy expertise plays a strategic, early-stage role in minimising carbon emissions before mechanical systems are even considered.

This foundational role in early design decisions is why such architects are often better suited to lead NZC healthcare projects. This collaborative approach ensures that each project phase — from design to post-occupancy — is undertaken with the goal of achieving long-term sustainability, financial savings, and improved environmental performance. This approach helps reduce risk, fosters greater buy-in from stakeholders, and ultimately leads to more successful, future-ready outcomes. By coordinating across estates, engineering, and clinical operations, architects ensure the whole system moves toward resilience; not just the buildings.

Conclusions: from carbon reduction to financial resilience

The NHS and private healthcare institutions face an urgent dual challenge: to deliver high-quality care while reducing their carbon footprint and operational costs. Net Zero strategies, when led by informed architects, are not just about compliance. They are about creating future-ready buildings that cost less to operate, are resilient to climate stress, and support better health outcomes.

Architects, and particularly those with expertise in sustainable design, offer a strategic solution to this challenge. Through careful planning and the integration of Net Zero Carbon strategies from the design phase through to post-occupancy in both new-build and retrofit, they can help all their clients organisations reduce carbon emissions, lower energy costs, and future-proof healthcare facilities.

As energy prices continue to rise, and climate change accelerates, the role of architects in achieving a Net Zero NHS, and the voluntary pledge of Net Zero Commitment, will only grow in importance. The transition to a Net Zero world is not just a distant ambition; it is an urgent necessity. By making the right investment decisions now, NHS Trusts and private healthcare providers can unlock significant financial and environmental value, ensuring a healthier future for both people and the planet.

Ultimately, the long-term benefits of transforming all healthcare estates into low-carbon, energy-efficient assets extend beyond financial savings. These transformations enhance local environments, create jobs in the green sector, and position the UK property sector as a leader in sustainability, setting an example for others to follow.

We established Cagni Williams Energy to help our clients with their climate targets, drive deep carbon reductions, and unlock significant long-term savings. Let us seize this moment to re-think healthcare design, not as a burden, but as one of the most impactful ways to deliver social, environmental, and economic value.

References

1 NHS Net Zero Building Standard. NHS England, 22 February 2023. https://tinyurl.com/2aavxb4v

2 Mills M. NHS Estates: Cost Modelling for Operational Net Zero. Gardiner & Theobald, 4 June 2021. https://tinyurl.com/4ejez6kh