Major EPC Overhaul Coming into Force on 15 June 2025

On 15 June 2025, a major update to Energy Performance Certificates (EPCs) will come into effect, introducing the most significant changes to the evaluation process in over a decade. The update, known as RdSAP 10, will change how energy ratings are calculated for existing homes in England and Wales.

Brown&Co is advising landlords, property owners and agents to prepare for these changes now. Both new and existing EPC ratings may be affected, particularly for properties close to the minimum standard currently required for rental.

What is changing

Energy assessors will be required to collect more specific information than before, including the type and condition of windows, the model and manufacturer details of heating systems, and the presence of smart heating controls.

One of the most notable changes is the increased importance of supporting documentation. Improvements such as upgraded boilers, additional insulation or double glazing will only be reflected in the EPC rating if appropriate evidence is provided. Without this, assessors will use conservative defaults, which could result in a lower rating even if energy improvements have been made.

The way heating systems are assessed is also being updated. Under the previous method, standard assumptions were applied when full system details were not available, often leading to inaccurate outcomes. RdSAP 10 prioritises real performance data, meaning landlords without clear documentation may see lower efficiency scores, which could affect a property's marketability or whether it meets legal letting standards.

The updated model also improves how floor area and insulation are calculated, offering a more accurate representation of a property's heat retention. In addition, flats and mid terrace properties, previously disadvantaged by older assumptions around heat loss, may see improved results under the new methodology.

Why it matters?

In England and Wales, rental properties must currently achieve a minimum EPC rating of E. With further tightening of energy standards coming soon, it has never been more important that EPC ratings reflect the true condition of a property.

Any energy efficiency works carried out, such as heating system upgrades or insulation improvements, should be properly documented. Receipts, installation certificates or time stamped photographs may be required to ensure these improvements are captured in future EPC assessments. Without this evidence, there is a risk that a property's rating could fall despite genuine upgrades.

These changes are expected to lead to more consistent and reliable EPC ratings.

Next steps

With the new rules coming into effect on 15 June 2025, we recommend landlords review the EPC status of their properties now. Where improvements have been made in recent years, it is important to ensure records are readily available for assessors. Properties assessed under older methodologies may benefit from a reassessment, particularly if updates were not previously documented.

At Brown&Co, we are committed to helping our clients navigate regulatory change and remain compliant. If you have concerns about your EPC or want to understand how these changes may affect your portfolio, please get in touch.

For more information, please contact Josh Bailey, Associate - Senior Lettings Negotiator, on 01603 629871 or email josh.bailey@brown-co.com