Tom Garrigan, Executive Director, BSRIA
With 85% of the buildings that will still be in use by 2050 already built, decarbonising the UK’s public and commercial estate represents one of the most pressing and complex challenges facing facilities managers today. Our building stock is among the oldest in Europe, and the regulatory landscape continues to evolve at pace. This means there is no universal solution. The only effective approach is one rooted in accurate assessment, where decisions are informed by robust evidence, not assumptions.
By starting with a detailed understanding of how each building performs, how it is used, and how occupants experience it, facilities managers can ensure that retrofit measures deliver maximum benefit. This approach makes it possible to achieve decarbonisation that is evidence-based, cost-effective and resilient, while also meeting compliance requirements and safeguarding long-term performance.
Investigation before intervention
Successful decarbonisation begins with investigation, not intervention. This means fully evaluating existing conditions before committing resources or planning works. A thorough performance assessment may draw on a range of non-invasive techniques, from thermal imaging and airtightness testing to acoustic analysis and post-occupancy evaluation. When these findings are considered together, they provide a holistic view of building performance, revealing inefficiencies, inconsistencies or vulnerabilities that are not immediately visible.
The value of this process is twofold. It allows targeted investment, avoiding unnecessary works or disruptive upgrades, and it ensures that improvements are tailored to the actual usage patterns of a building, rather than being based on broad generalisations. This approach also gives occupants a voice in shaping the outcome. Direct input from users – whether through surveys, interviews or informal conversations – can uncover comfort issues, behavioural patterns and operational constraints that purely technical assessments may overlook. Engaging those who use the building every day encourages a shared sense of responsibility in achieving, and maintaining, operational sustainability goals.
We saw the benefits of this approach first-hand during the recent retrofit of BSRIA House, our own headquarters. Rather than implementing a list of generic upgrades, we began with rapid, cost‑effective fabric assessments that established a clear performance baseline. This enabled us to identify and prioritise the interventions that would deliver the greatest value. The results were significant: building airtightness improved by 35 per cent, Scope 1 and 2 emissions reduced by 28 per cent, and occupant satisfaction rose by 14 per cent, all while the building remained fully operational.
Achieving compliance
Today’s facilities managers are being asked to balance the demands of day-to-day operations, occupant comfort and long-term asset performance with an increasingly stringent set of legislative requirements. The Building Safety Act, the Future Homes and Buildings Standards, changes to Energy Performance Certificates and associated reporting obligations are reshaping the compliance landscape.
While it is easy to see these developments as additional burdens, they present an opportunity do better. Adopting a measurement-led approach to decarbonisation naturally supports compliance by providing detailed performance outcomes and documentation that reduce risk and liability in the long term.
Central to this is a fabric‑first mindset. However advanced an energy system may be, it will only deliver its full potential if the building envelope itself is efficient. Improving insulation, tackling thermal bridges and eliminating air leakage will reduce demand at source, ensuring that any energy generated is used as effectively as possible. These improvements not only ensure a building is more energy efficient, but they also pave the way for the successful integration of low‑carbon technologies, whether now or in the future.
Long-term performance
Independent, third‑party verification forms the bedrock of a credible decarbonisation strategy. Objective testing ensures that the initial performance of a building is thoroughly understood and provides a benchmark against which improvements can be measured.
Construction professionals who rely on independent measurement, rather than self‑certification, report markedly higher confidence in their results. In fact, our research shows that almost half of the architects and engineers surveyed expressed greater trust in their outcomes when physical measurements had been taken by an impartial party. This underlines the fact that robust data is important for accountability and transparency in both the initial phase of a retrofit project and for continuous improvement.
This data only becomes more valuable over time: retrofit should not be viewed as a one‑off event. Ongoing performance management is essential if gains are to be protected. Advances in cloud-based in‑use monitoring now allow facilities teams to track performance in real time, identifying inefficiencies before they become costly issues, helping to ensure that buildings will continue to operate as intended. This capability also provides continual verification of retrofit outcomes, proving that savings and improvements are maintained in practice, not just on paper.
A driver for positive change
The idea that pursuing Net Zero requires compromise on comfort, quality or operational efficiency is a misconception. When retrofits are based on diagnostics, not assumptions, they can enhance multiple aspects of a building at the same time by improving efficiency, resilience, user wellbeing and long-term value. For facilities managers, particularly in the public sector, this turns compliance from a procedural obligation into an opportunity to create better environments for users, and the planet.
Decarbonisation will not be easy, but when approached with accurate measurement, occupant engagement and a commitment to continuous improvement, it becomes a powerful driver for positive change. However, the time to act is now.
This article appeared in the September 2025 issue of Energy Manager magazine. Subscribe here.
