Blog: Why Your Building’s EPC Rating Could Change Overnight
In her latest blog, Madelaine Bradley shares key insights from Footprint+ on the evolving role of Energy Performance Certificates (EPC) and what the latest changes mean for property owners, investors and developers.
As the Standard Assessment Procedure (SAP) continues to evolve, EPCs are becoming a more accurate reflection of how buildings perform in practice, helping to close the long-recognised gap between predicted and actual energy performance.
However, it is not just the assessment methodology that is changing. The benchmarks themselves are shifting, bringing new challenges and opportunities for the property sector.
EPC Ratings Are Becoming a Business Risk
With residential and commercial properties expected to achieve a minimum EPC rating of B by 2030 to remain lettable, many organisations are reassessing their property portfolios and asking important questions:
- Which assets are at risk of becoming non-compliant?
- What level of investment will be required?
- Should improvements be made now rather than later?
Increasingly, EPC ratings are influencing asset value, investment decisions and long-term portfolio resilience. What was once viewed primarily as a compliance exercise is becoming a key consideration in asset management.
Why Ratings Can Change Overnight
One of the biggest concerns raised at Footprint+ was the reliability of EPC ratings as the underlying assessment methodology continues to evolve.
Software updates alone can significantly alter a building’s rating. In one example, a building dropped from a B to a C overnight following a methodology update, despite no physical changes being made. Simon Smith of Vital Direct also highlighted examples of buildings moving from a C in 2012 to an F in 2022, making them effectively unrentable under current regulations.
These examples demonstrate why maintaining an up-to-date EPC is increasingly important, particularly following the significant SAP methodology changes introduced in 2022.
The Shift Towards Electrification
Much of the change in EPC methodology reflects the UK’s transition away from fossil fuels towards cleaner electricity generation.
In 2012, electricity generation relied heavily on fossil fuels. Today, around 51% of the UK’s electricity comes from renewable sources, meaning EPC calculations now place greater emphasis on low-carbon heating solutions and increasingly penalise fossil fuel systems.
This transition is also being driven by wider concerns around energy security, geopolitical instability and the need for greater energy independence. As a result, technologies such as heat pumps are becoming central to future building services strategies.
Property owners should begin planning for electrification now, ensuring their buildings can accommodate low-carbon heating technologies as regulations continue to evolve.
Bringing Occupiers on the Journey
Technology alone will not deliver better building performance.
Many occupiers remain more familiar and comfortable with traditional gas heating systems, making them hesitant to embrace newer technologies such as heat pumps. Concerns around reliability, disruption and operational costs can create resistance to change.
Successful projects therefore require more than good design. Building users need clear guidance on how their systems operate to ensure they are used efficiently and comfortably. Sustainability consultants, M&E engineers and designers all have an important role in supporting occupiers after handover to maximise performance.
Closing the Performance Gap
Although EPCs continue to improve, they remain based on standardised assumptions rather than actual building performance.
Current EPC assessments use fixed climate data and standard occupancy assumptions, meaning they cannot fully capture how a building performs in reality.
Alternative modelling approaches, such as TM54, provide a more accurate picture by using detailed 3D modelling and real-world weather data to predict operational energy use over time. These methods help designers better understand likely energy consumption and further reduce the performance gap between design and operation.
Preparing Your Portfolio
For many property owners, the most practical opportunity to improve EPC performance is during refurbishment or between tenancies.
Taking a fabric-first approach remains fundamental. Improving insulation, reducing air leakage and enhancing the building envelope should form the foundation of any energy strategy before investing in new technologies.
Early collaboration is equally important. Engaging M&E engineers and sustainability consultants from the outset helps ensure buildings are designed around future heating systems, avoiding costly redesigns later in the project.
Looking Ahead
While EPCs remain an imperfect science, each update is moving them closer to representing real building performance.
The next major milestone will be the introduction of the Future Homes Standard and the first edition of the Home Energy Model, which promises to further improve how energy performance is assessed.
As the methodology continues to evolve, understanding how these changes affect your buildings will become increasingly important—not just for compliance, but for protecting asset value, supporting investment decisions and creating more resilient property portfolios.