What Evidence Can Improve Your EPC Accuracy? Documents to Prepare Before Your Assessment

One of the most common reasons a property receives a lower EPC rating than expected is missing evidence — not missing insulation.

EPC assessments follow an approved methodology. Where a qualifying feature cannot be seen during the inspection or supported by documentation, the assessment may need to rely on standard assumptions based on the age and type of the property. For owners who have invested in improvements, that can mean the certificate does not reflect the work that was actually done — sometimes the difference between bands, as explained in our poor EPC rating guide.

Founded in 2015 by Jino Jose, EPCRATE helps London homeowners and landlords prepare properly for assessments so that qualifying features are recognised appropriately. Call 020 3488 4142 to book.

Why Evidence Matters

Many energy efficiency features are hidden once installed:

• Cavity wall insulation sits inside the wall.
• Internal or external solid wall insulation may not be measurable on the day.
• Underfloor insulation is rarely accessible.
• A boiler’s exact specification may not be visible from the unit alone.

Where these cannot be verified, the approved methodology applies default assumptions — and defaults for older properties are often conservative. Appropriate documentation allows the assessor to record the actual specification instead.

Documents Worth Preparing

Insulation

• Cavity wall insulation guarantees (for example CIGA certificates).
• Installer certificates or invoices identifying the property and the work.
• Loft insulation receipts where access on the day is restricted.
• Photographs taken during installation, where available.

Windows and Glazing

• FENSA or CERTASS certificates for replacement windows.
• Building Control approval where windows were part of wider works.

Heating and Hot Water

• Completion certificate.
• Manufacturer documentation identifying the model.
• Records for heating controls, cylinder upgrades or heat pump installations.

Building Works

• Building Control completion certificates for extensions and conversions.
• Architect or contractor specifications confirming construction details.

Renewables

• Installation certificates for solar PV or solar thermal systems.
• MCS certificates where applicable.

What Evidence Can and Cannot Do

Evidence helps the assessment reflect the property accurately — it does not guarantee a particular rating.

Final results always depend on the property as a whole, the supporting evidence available and the approved assessment methodology. Documentation requirements also depend on current assessment conventions, so your assessor can confirm what can be accepted on the day.

Preparing for Your Assessment: A Simple Checklist

• Gather certificates and guarantees for any insulation work.
• Locate FENSA/CERTASS certificates for replacement windows.
• Find the completion certificate or service records.
• Collect Building Control documents for extensions or conversions.
• Ensure loft access is available where possible.
• Have the documents ready at the property for the assessor’s visit.

A few minutes of preparation can make a meaningful difference to how completely the assessment captures your property. If your goal is reaching a higher band, our guide to getting an EPC C rating covers the improvement side.

Want Certainty Before the Certificate Is Lodged?

EPCRATE is the only London provider offering a Draft EPC service — you can review the assessment outcome and discuss the impact of your evidence before the certificate is lodged on the national register. Planning works? See our guide to EPCs before renovation.

Once lodged, EPCRATE certificates are typically registered within 24 hours of the assessment, and a domestic EPC generally remains valid for 10 years. You can read more in our guide to how long an EPC lasts.

Why Choose EPCRATE?

• Founded in 2015 by Jino Jose.
• DEA Accredited.
• ★★★★★ Trustpilot Reviews.
• ★★★★★ Google Reviews.
• Same-day appointments available where possible.
• Coverage across all 32 London boroughs.
• Only London provider offering a Draft EPC service.
• Greater London Energy Efficiency Awards – Commended 2024.
• Greater London Energy Efficiency Awards – Highly Commended 2025.

Frequently Asked Questions

Why does evidence matter for an EPC?

Where qualifying features such as insulation cannot be seen or evidenced, the approved methodology may apply standard assumptions based on property age. Documentary evidence helps the assessment reflect the actual specification.

What documents should I prepare for an EPC assessment?

Useful documents include insulation certificates or guarantees, FENSA or CERTASS certificates for windows, Building Control completion certificates, boiler installation records and photographs taken during works.

Can old renovation receipts be used as EPC evidence?

Documentation requirements depend on the approved assessment conventions. Formal certificates and Building Control records generally carry the most weight — your assessor can confirm what can be accepted.

Will providing evidence guarantee a better EPC rating?

No specific rating can be guaranteed. Evidence helps ensure qualifying features are recognised appropriately, but final results depend on the property and the approved methodology.

Can I check the likely outcome before my EPC is lodged?

Yes — EPCRATE is the only London provider offering a Draft EPC service, allowing you to review the assessment outcome before the certificate is lodged on the national register. Call 020 3488 4142.

Booking an EPC and want it done right first time? Call EPCRATE on 020 3488 4142 — we will tell you exactly what to have ready.

Service	Price
1 Bedroom EPC	£59
2 Bedroom EPC	£69
3 Bedroom EPC	£79
EPC + Floor Plan Bundle	£118