EPC methodology changing from 15 June – good news or bad?
The Energy Performance Certificates (EPC) system for domestic buildings is being overhauled from 16 June 2025, with the aim of producing more accurate and detailed assessments.
EPCs for existing houses are calculated using the Reduced Data Standard Assessment Procedure (RdSAP) – a simplified version of the Standard Assessment Procedure (SAP) used for new builds.
This simplification is necessary because existing homes tend to lack the full range of data required for a full SAP assessment.
The introduction of the new RdSAP 10 methodology represents a major update. It seeks to address some of the long-standing limitations of the outgoing system, which relies on default assumptions about materials and construction which can produce misleading results for traditionally built homes.
Refining the methodology for RdSAP is an attempt to provide more a reliable assessment of a home’s energy performance.
Key changes include:
- Improved assessment of heating systems
The new methodology incorporates the latest data to give a more accurate appraisal of the different types of systems used. Electric heating systems, including heat pumps, may see a house achieve an improved rating due to changes in how energy use are calculated.
- Better recognition of renewable technologies
Properties using photovoltaic panels or solar thermal systems may see improved ratings due to more precise methods for evaluating their contributions.
- More detail on building elements
The new RdSAP methodology also allows assessors to capture much more precise details about windows, wall exposure, wall insulation and ventilation, rather than being forced to rely on a relatively small number of preset options. This should enable a more nuanced picture of the building’s performance.
- A new age band for modern homes
The updated system introduces a new age band to reflect newer homes will have been built to higher energy-efficiency standards. This will apply to new homes built in 2023 onwards in England, Wales and Northern Ireland and from 2024 in Scotland.
The changes aim to support national goals such as reducing carbon emissions, tackling fuel poverty, and creating warmer, more comfortable homes.
What are the implications for rural landlords?
Although the new methodology requires assessors to collect more detailed information – potentially making assessments more time-consuming and costly – the trade-off is improved accuracy.
This improved accuracy could be critical in light of the Government’s proposals to require landlords in the private-rented sector to achieve an EPC of ‘C’ by 2028 for new tenancies and by 2030 for existing ones. A clearer and more transparent EPC framework should assist landlords when considering investment decisions associated with improving energy performance.
However, the accuracy of assessment will increasingly depend on documentation provided by landlords. Keep thorough records of energy improvements, such as insulation upgrades and heating system installations.
If you would like to discuss the changes and how we can help with energy efficiency improvements to your property, please contact Alexander Macfarlane.
