Retrofit will only succeed if we move beyond assumptions and start measuring what really matters, warns Sara Edmonds, co-director of the National Retrofit Hub
Retrofit is central to the UK’s response to the climate crisis. It underpins progress on carbon reduction, fuel poverty, energy security and the condition of the nation’s homes.
Yet as delivery accelerates, a fundamental issue remains unresolved: success is still too often defined by predicted performance, not by what actually happens in homes and communities.
The National Retrofit Hub’s Measuring Outcomes & Impact Evaluation (MOIE) project was established to address this gap. Supported by Impact on Urban Health, Arup and TrustMark, with strategic input from the Royal Academy of Engineering, and collaboration with Centric Lab, the project responds to a growing concern across policy and practice that current approaches to evaluation are too narrow to capture what retrofit is really delivering.
Much of the UK’s retrofit framework relies on modelled performance, particularly through Energy Performance Certificates (EPCs). While EPCs support benchmarking at scale, they were never designed to reflect how homes perform in use or how retrofit affects people’s health, comfort and daily lives.
Evidence from delivery programmes shows that predicted performance can diverge sharply from lived reality. Homes may meet technical standards on paper while remaining cold, damp, poorly ventilated or expensive to run. Without systematic pre- and post-intervention monitoring, these issues often remain hidden until problems escalate, sometimes resulting in poor health outcomes, resident dissatisfaction and costly remediation.
At the same time, national audits have repeatedly highlighted weaknesses in outcome monitoring across energy efficiency schemes. These warnings have been consistent over more than a decade, yet they remain largely unaddressed. As retrofit activity prepares to scale up, the consequences of this gap are becoming harder to ignore.
MOIE starts from a different premise: retrofit is not just a technical upgrade to buildings but a health-shaping intervention that interacts with place, systems and lived experience.
Housing conditions influence physical health through temperature, air quality, damp and noise. They also shape mental health through stress, insecurity, overcrowding and disruption. These impacts are not evenly distributed. Structural inequalities mean that poorer quality housing and environmental stressors are disproportionately experienced by marginalised communities.
Yet most retrofit programmes still struggle to account for these realities. Health, comfort and usability are rarely embedded into success criteria, despite being central to how people experience their homes. As a result, retrofit risks delivering compliance without improvement, and efficiency without equity.
The MOIE project points to a clear shift that is now needed across policy and delivery.
First, success in retrofit must be defined more broadly. Carbon reduction and bill savings remain vital, but they are not sufficient on their own. Health, comfort and lived experience must be valued as core outcomes, not secondary benefits.
Second, measured performance must complement modelled assumptions. Post-intervention monitoring, including approaches that draw on real-world data, is essential to understanding whether retrofit is actually improving homes in practice. Without this, policymakers and delivery partners are effectively flying blind.
Third, communities must be supported to shape and assess outcomes. Tools such as Community Health Impact Assessments (CHIAs) offer a practical way to centre lived experience, surface local realities and ensure that interventions respond to the specific identities and needs of places. This is not about consultation for its own sake but about improving decision-making and accountability.
Sara Edmonds, co-director of the National Retrofit Hub, said: “Retrofit will only succeed if we move beyond assumptions and start measuring what really matters. That means understanding how homes perform in use, how people experience change and how place shapes outcomes. The MOIE project shows that better evaluation is not only possible but essential if retrofit is to deliver lasting benefits.”
MOIE has been developed through extensive collaboration with delivery partners, researchers and communities, including contributions from Centric Lab, Dr Kate Simpson and many practitioners and residents who took part in workshops and interviews. This collaborative approach reflects the project’s core message: better outcomes depend on better connections between data, practice and lived experience.
A set of practical resources have been produced to support this shift, including a baselining review of current measurement practice, a new insights paper on place-based health outcomes, guidance on the role of CHIAs in retrofit and a collection of Innovator Profiles showcasing emerging approaches in practice.
Together, these outputs provide a foundation for change, but the challenge now is uptake. As retrofit continues to scale, the sector faces a choice: continue to rely on arrow metrics that obscure risk and value or invest in evaluation approaches that reflect what people actually experience in their homes and neighbourhoods.
Measuring what matters is not an optional extra. It is essential to delivering retrofit that is effective, equitable and worthy of public trust.
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