Understanding the New EPC Changes: What Landlords Need to Know About RdSAP 10 and the Rising Costs

Understanding the New EPC Changes: What Landlords Need to Know About RdSAP 10 and the Rising Costs

As of 15th June 2025, the UK is implementing significant changes to the Energy Performance Certificate (EPC) assessment methodology with the introduction of RdSAP 10. These updates aim to enhance the accuracy of EPCs but also bring implications for landlords, including potential increases in assessment costs.

Top 10 Changes in RdSAP 10 Landlords Should Be Aware Of

1. Enhanced Data Collection Requirements
   Assessors are now required to gather more detailed information during property visits, such as precise measurements of all windows, identification of wall types, and specifics about insulation thickness.

2. Introduction of Age Band M
   A new age band, 'M', has been added for properties built from 2023 onwards, allowing for more accurate categorization of modern homes.

3. Detailed Wall Insulation Recording
   Insulation thickness can now be recorded in 25mm increments, providing a more precise understanding of a property's energy retention capabilities.

4. Refined Room-in-Roof Assessments
   Two distinct types of room-in-roof constructions are now recognized, improving the accuracy of assessments for properties with converted loft spaces.

5. Mandatory Evidence for Heating Systems
   Assessors must now verify heating system efficiencies with actual evidence, such as model numbers or manufacturer data. Without this, default (often lower) efficiency ratings will be applied.

6. Improved Assessment for Flats and Terraced Homes
   The new methodology adjusts how heat loss is calculated for flats and terraced properties, which were previously disadvantaged by default assumptions, potentially leading to improved EPC ratings for these types of properties.

7. Inclusion of Renewable Technologies
   RdSAP 10 now accounts for technologies like photovoltaic (PV) diverters and battery storage, reflecting the growing adoption of renewable energy solutions in homes.

8. Detailed Ventilation and Lighting Data
   Assessors are required to collect more comprehensive data on ventilation systems and lighting, including the number and type of light fittings, enhancing the overall assessment accuracy.

9. Recognition of Mechanical Ventilation Systems
   The updated methodology includes options to record mechanical ventilation systems, acknowledging their impact on a property's energy performance.

10. Potential for Increased Assessment Costs
    Due to the additional time and detail required in assessments, costs for EPCs are expected to rise. Assessors anticipate spending an extra 20-30 minutes per property, which may lead to price increases ranging from £10 to £30, depending on property size and complexity.

Why Are EPC Costs Increasing?

The comprehensive nature of RdSAP 10 assessments necessitates more time and effort from assessors. The detailed data collection, requirement for evidence-based inputs, and inclusion of new technologies mean that assessments are more labor-intensive. Consequently, assessors are adjusting their pricing structures to reflect the increased workload and to ensure the delivery of accurate and valuable EPCs. 

What Should Landlords Do Now?

• Gather Documentation: Ensure you have all relevant documentation for any energy efficiency improvements made to your properties, such as insulation upgrades or heating system installations.

• Schedule Assessments Early: With the anticipated increase in assessment times and potential backlogs, it's advisable to schedule EPC assessments promptly to avoid delays.

• Consult with Professionals: Engage with accredited energy assessors to understand how the changes may specifically impact your properties and to receive guidance on potential improvements.

Further Information

For a comprehensive overview of the RdSAP 10 changes, please visit the Energy Trust's detailed guide: RdSAP 10 Major Changes: What You Need to Know