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Energy Performance Certificate (EPC)

Energy Performance Certificate (EPC) rating check and evidence guide

Use this page if you need to check an Energy Performance Certificate (EPC) rating, gather documents before a survey, or understand which evidence helps when RdSAP defaults are being overridden.

It combines EPC basics, survey-day prep, and the evidence checklist that supports heat pump, solar, retrofit, and audit work. You do not need every document. Phone photos are fine if that is what you have.

Quick EPC check

How to check your EPC rating and what to gather before a survey

Start with the latest EPC, then collect anything that proves changes to the property or systems since it was issued.

Current EPC

Check the current certificate first

  • Latest EPC certificate or report if you have it
  • Current EPC rating and recommendations
  • Issue date so you know how old the data is
  • Any past reports that show how the rating changed
Documents

Gather anything that proves improvements

  • Building Control completion certificates
  • FENSA or CERTASS glazing paperwork
  • Insulation invoices, certificates, or retrofit paperwork
  • MCS, DNO, or commissioning documents for renewable systems
Access

Make key evidence easy to inspect

  • Electric meter, cut-out, and consumer unit if relevant
  • Boiler, heat pump, and cylinder cupboard if applicable
  • Loft hatch if insulation evidence may matter
  • Outdoor access if solar, ASHP, or external elements need checking
EPC evidence and RdSAP support

What EPC evidence helps before an EPC update or audit?

For RdSAP on existing dwellings, audits check that EPC inputs are supported by site evidence: photos, notes, and a sketch or plan with dimensions. The working rule is simple: if you override a default, you need evidence.

Site notes

What we record (RdSAP)

  • Age band / construction notes (and what you observed)
  • Storeys, extensions, and any unusual layout notes
  • What’s measured vs assumed (and why)
Floor plan

Sketch + key dimensions

  • Sketch/plan with key dimensions used for areas
  • Notes for treated floor area boundaries and extensions
  • Any supporting plans if the homeowner has them (optional)
Photos

Always take these photos

  • Front/rear elevation (property type/context)
  • Heating system make/model/spec plate (boiler/heat pump)
  • Hot water cylinder + insulation (if present) / spec plate
  • Heating controls (thermostat/programmer, TRVs if present)
  • Loft hatch + loft insulation depth/type (if accessible)
  • Glazing (showing double/triple glazing where visible)
  • Renewables: PV inverter / battery / heat pump MCS docs if provided
Defaults vs proof

Evidence needed when EPC or RdSAP defaults are overridden

RdSAP uses conventions and default assumptions when evidence isn’t available. If you claim an improvement, it must be supported by documentation or clear on-site evidence.

Insulation

Proof beats assumptions

  • Loft insulation: depth photo + any invoice/certificate
  • Cavity wall insulation: guarantee/certificate (e.g. CIGA) or installer paperwork
  • Solid wall insulation (EWI/IWI): completion paperwork/specs
  • Floor insulation: documentation if not directly visible
Glazing

Dates/specs matter

  • FENSA/CERTASS certificates (or equivalent installer paperwork)
  • Photos showing glazing type where visible
  • Any U‑value specs if the homeowner has them
Systems

Make/model + controls

  • Boiler/heat pump make/model and commissioning/Benchmark if available
  • Controls evidence (programmer/thermostat, zoning, TRVs)
  • Solar/battery: MCS + DNO (G98/G99) if available, plus inverter/battery specs
Building regs / sign-offs

Completion certificates & approvals

  • Building Control completion certificates (extensions, conversions, major alterations)
  • Competent Person Scheme certificates (where applicable)
  • Any sign‑off paperwork related to insulation installs or upgrades
Windows / doors

Glazing certificates & specs

  • FENSA certificate
  • CERTASS certificate
  • Installer paperwork showing window type/spec (double/triple glazing, if known)
  • Any documentation showing U‑values (if you have it)
Insulation

Proof of insulation measures

  • Loft insulation invoice/certificate (depth/type if documented)
  • Cavity wall insulation certificate/guarantee (e.g. CIGA or installer paperwork)
  • External/Internal wall insulation documentation (EWI/IWI)
  • Floor insulation documentation (suspended/solid where applicable)
  • PAS2030 / TrustMark paperwork (if done via retrofit schemes)
Heating / hot water

System details & commissioning

  • Boiler/heat pump commissioning certificate (if you have it)
  • Benchmark booklet / service record (for boilers)
  • Heat pump documentation (make/model, installer paperwork)
  • Cylinder make/model/spec plate photo (hot water cylinder)
  • Heating controls paperwork (thermostat, zoning, programmers) if available
Solar / battery

Renewables certificates

  • MCS certificate for solar PV / battery / heat pump (if applicable)
  • DNO paperwork (G98/G99) if you have it
  • Inverter/battery make/model paperwork (or spec plate photos)
Existing EPC

Past EPC / reports

  • Latest EPC certificate/report (printout or on phone)
  • Any retrofit assessment or previous energy reports (if relevant)
  • Recent energy bills (optional): last ~12 months if easy to find (helps with context, not required for audit)
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