EPC RdSAP 10 Updates

Exciting developments are on the horizon for energy assessment procedures.

EPC RdSAP 10 Updates will bring the biggest change to the way data is collected and processed to produce your Energy Performance Certificate. The latest version of the software engine behind the production of EPC reports, RdSAP version 10 , is set to launch in April 2024. Alongside the proposed rollout of the Home Energy Model, these updates signify more than just procedural shifts; they mark a significant stride toward sustainable living practices and the UK’s ambitious Net Zero targets.

Practical Impact on EPC Assessments:

Whereas EPC assessments traditionally took between 30-60 minutes, the introduction of more thorough requirements as detailed below will extend this by an estimated additional 20-30 minutes per property, reducing the number of appointment slots available in a day. This substantial increase in on-site time will, regrettably, translate to higher costs for EPC assessments. Future inaccuracies in EPCs could have a significant impact on the property, underlining the importance of accurate assessments aligned with the latest standards.

EPC RdSAP 10 Updates Assessor

Some of the changes to the EPC RdSAP 10 Updates data entries include:

– Window measurements and orientation required for all windows

– Location of each window allocated to main walls or each extension, or alternative walls

– Thermal properties of insulation revised

– Roof insulation details have more options

– Floor insulation revised; heated basement details added

– Table of Window U-Values expanded

– U-values of brick wall revised to account wall thickness

– U-values of stone walls revised

– Curtain wall added as new wall type

– Window shutters added as a new feature

– Hot water tank size included

– Hot water tank insulation included

– Room in roof (RR) revised to take into the account all elements including continuous main wall

– Additional alternative/shelter wall added

– Mechanical ventilation is treated as in full SAP allowing PCDB entry, still allowing default values

– PV calculated as in SAP10.2

– PV Diverter for water heating added

– PV Batteries added

– Ventilation algorithm allows more options

– Air pressure test result can be used if available

– New age-band M added, and all tables of U-values updated

– Data for Isle of Man added for completeness of information

– Table 32 with the RdSAP10-specific fuel prices replaces fuel prices in Table 12 of SAP10.2

– RdSAP10-specific metrics added to replace SAP metrics in SAP10.2

– Small scale hydro added as in SAP10.2

– Flue gas heat recovery -calculation according to SAP 10.2.

– Waste water heat recovery – calculation according to SAP 10.2.

– Heat pumps – Calculation according to SAP 10.2.

Changes to Table 21 of improvement measures (former RdSAP Appendix T) include:

– Improved U-values revised for all building elements

– Measure to insulate party wall removed

– Order of measures for Northern Ireland removed

– Air and ground source heat pumps not alternative measures anymore

– PV battery and PV diverters added

The Positives:

The RdSAP 10 update presents a significant advantage by highlighting properties with high EPC ratings and renewable technologies. Such properties will appeal to the growing market of environmentally and cost-conscious consumers, as we have written about previously. This update has the potential to enhance a property’s marketability with the rising cost in utilities making more energy efficient homes increasingly appealing. Leveraging these changes, innovative agents and savvy owners can emphasise the benefits of sustainable living and the financial advantages of owning or renting energy-smart properties.

EPC RdSAP 10 Updates Rating Chart

The Home Energy Model – A Game Changer:

The proposed Home Energy Model, scheduled for introduction in 2025, represents a transformative leap forward from existing methodologies used to assess home energy performance. Currently in the consultation phase, this model is poised to integrate cutting-edge technologies and approaches. While specifics on its digital presence remain under discussion, its foundation in open-source development and modular design strongly suggests a future where the model is accessible via a digital platform, be it online or through software applications. Such a format is designed for broad adoption, ensuring seamless updates and enhancements in line with technological advancements and expanding datasets. Furthermore, this model anticipates future integrations with financial institutions, local authorities, and other key stakeholders, enhancing the efficiency and effectiveness of energy performance assessments and driving forward sustainable housing initiatives across sectors.

Our Commitment to Supporting You:

Navigating these updates can be challenging, but our team is here to provide the expertise and support needed to seamlessly adapt to these new standards. We’re committed to helping you optimise your properties energy rating, improving your energy efficiency, reducing bills and improving your quality of life in the home environment.


The RdSAP 10 update epitomises the UK’s unwavering commitment to energy efficiency and sustainability. By integrating cutting-edge data, acknowledging the value of supplementary data, and prioritising factors like air tightness, RdSAP 10 sets a new benchmark for residential energy assessments.

For homeowners and prospective buyers, RdSAP 10 offers a more robust and holistic perspective on a property’s energy performance. It empowers individuals to make informed decisions regarding energy efficiency enhancements and investments, thereby fostering a greener and more sustainable future.

In an era fraught with environmental challenges, updates like RdSAP 10 can play an instrumental role in championing energy efficiency and steering us towards a more sustainable lifestyle.

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