15 JUNE 2025 EPC METHODOLOGY CHANGES

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15 JUNE 2025 EPC METHODOLOGY CHANGES

On 15 June 2025, a major overhaul of Energy Performance Certificate (EPC) calculations will take place with the introduction of RdSAP 10. This update, which revises the methodology for domestic energy assessments, aims to provide more accurate EPCs that better reflect how homes are used and help homeowners make informed decisions about energy efficiency. 

Key Changes in RdSAP 10:

  • More Data Collection:

Energy assessors will gather more detailed information about properties, including specific types of glazing, heating system details (based on evidence like model numbers), and the presence of smart heating controls. 

  • Prioritisation of Evidence:

The new methodology prioritises actual evidence over default assumptions when assessing heating systems and other aspects of a property. 

  • Improved Accuracy:

The changes are designed to provide a more accurate reflection of a property’s energy performance, considering factors like insulation, glazing, and heating systems. 

  • Increased Cost:

Due to the more detailed data collection and assessments, there may be an increase in the cost of EPCs. 

  • Impact on Heating Systems:

Electric heating systems may see improved ratings as the new methodology acknowledges that electricity can be a cleaner source of energy than mains gas. 

  • Emphasis on Renewable Technologies:

The new guidance will also offer a more comprehensive assessment of homes using renewable energy technologies. 

Impact on Landlords and Tenants:

  • Increased Accuracy:

EPCs will provide a more accurate representation of a property’s energy performance. 

  • Informed Decisions:

The more accurate assessments will help homeowners and landlords make informed decisions about energy efficiency improvements. 

  • Compliance with Regulations:

The updated EPCs will need to be used for new tenancies and sales from the date of implementation. 

  • Potential for Increased Costs:

The increased data collection and assessment time may lead to higher costs for EPC assessments. 

Important Note: Existing EPCs will remain valid until they expire, even after the RdSAP 10 update is implemented.