The new EPC criteria...

1. What is RdSAP 10?

RdSAP 10 is the updated version of the Reduced Data Standard Assessment Procedure for Energy Performance Certificates (EPCs), replacing the previous methodology in mid‑June 2025 .

It represents the most significant update in over a decade, designed to reflect modern building practices, technologies, and energy usage.

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2. Key Enhancements & Benefits

✅ Improved Accuracy & Fairness

• Measured data for windows, walls, roofs, etc. – Each window must now be measured individually, and wall/roof/ventilation details captured precisely, reducing reliance on assumptions .

• Better modelling for flats/terraced homes – Enhanced heat-loss calculations offer more equitable ratings for these property types .

🌱 Integration of Low-Carbon Technologies

• Inclusion of PV batteries/diverters, heat pumps, MVHR systems – Reflects real-world adoption and allows these technologies to positively influence EPC scores .

• Carbon factor updates – Lower emission factor for electricity (from 0.5 kg to 0.13 kg per kWh) rewards electric and renewables-based heating .

3. Implications for Stakeholders

🔧 Homeowners & Tenants

• More precise EPCs = better insight into energy use – You’ll get reports that more accurately reflect your home’s efficiency and better guidance on upgrades .

• Potential uplift in ratings – Well-upgraded homes may benefit through higher EPC ratings, especially those with documented insulation, renewables, and airtightness .

• Slightly higher assessment costs – Surveys take about 20–30 minutes longer and may cost more (Surveyors UK mentioned increased complexity; Green Energy Switch noted price rises from ~£90 to £105+VAT) .

🏢 Landlords & Investors

• Better asset data – More detailed and accurate EPCs support investment decisions, compliance, and tenant attraction .

• Stricter evidencing requirements – Efficiency measures need documentation (e.g., invoices, manuals); undocumented upgrades may be ignored or penalised .

• Ratings could shift – Some may improve, but others might drop if defaults were previously optimistic .

🛠 Energy Assessors

• Mandatory retraining & software updates – Mandatory to comply with new data measurement practices .

• Longer inspections & higher benchmarks – On-site time will increase, requiring greater skill and rigour .

• Costs reflect workload – Surveyors (e.g., Green Energy Switch) are raising fees to reflect additional effort .

4. Recommendations

1. Document everything – Keep all receipts, certificates, manuals for insulation, heating, solar, batteries, air tests.

2. Plan ahead – Landlords and homeowners should schedule EPCs early, especially if tightening rental requirements or selling.

3. Budget appropriately – Expect EPC costs to rise. Ensure your accountant/finance team is aware.

4. Engage accredited assessors – Choose DEAs experienced with RdSAP 10 to ensure accurate and efficient assessments.

5. Use EPCs strategically – Leverage detailed insights for retrofit planning and to secure funding like SHDF/ECO.

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6. Conclusion

RdSAP 10 delivers significant improvements in the accuracy, fairness, and relevance of EPCs, especially for homes with modern upgrades or renewable systems. While this comes with longer assessments, increased costs, and requirement for stronger evidence, the overall outcomes—better retrofit guidance, improved asset profiles, and alignment with sustainability goals—make the update a clear and substantial step forward for homeowners, landlords, tenants, and assessors alike.

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For tailored advice based on your situation—such as funding routes, documentation needs, or retrofit recommendations—I’m happy to assist further.