A domestic EPC assessment is a non-invasive survey by an accredited assessor GOV.UK. Nothing is drilled, lifted or dismantled: the assessor records what can be seen and evidenced, feeds it into the RdSAP calculation, and lodges the result on the register.
What the assessor inspects
- Construction and fabric. Wall type (cavity, solid, system-built), roof and floor construction, insulation where visible or evidenced.
- Windows and doors. Under RdSAP 10, windows are measured individually rather than assumed from the property's age band Elmhurst RdSAP 10.
- Heating. Boiler or heat pump make and model, controls (thermostat, TRVs, programmer, smart controls), hot water arrangements.
- Ventilation and airtightness. Now recorded in detail, including mechanical ventilation and any air pressure test results you hold Elmhurst RdSAP 10.
- Lighting and generation. Low-energy lighting share, solar panels, battery storage.
Why your paperwork now matters
RdSAP 10, live since 15 June 2025, moved the methodology from assumption-led to evidence-led Elmhurst RdSAP 10. Where an assessor cannot see or evidence a feature, they must enter a conservative default. Cavity wall insulation with no visible drill pattern and no paperwork may score as uninsulated. The practical rule: every invoice, guarantee and installation certificate you can produce protects points your house has already earned.
Worth digging out before the visit
- Boiler installation and latest service record
- Insulation invoices or guarantees (cavity, loft, floor, solid wall)
- Window and door installation certificates
- Solar or battery installation paperwork
- Any air pressure test result
How long it takes
Longer than it used to. The additional measurement and evidence requirements of RdSAP 10 mean more time on site than the pre-2025 walk-round Elmhurst RdSAP 10; exact duration depends on the size and complexity of the property, so we will not invent a minutes figure for you.
Preparing legitimately
You cannot stage your way up a band, but you can avoid losing points by absence of evidence: paperwork out, access clear, and every improvement documented. If the visit is about a letting deadline, read the improvement guide first so the works happen before the survey rather than after it. And check the register GOV.UK register before booking at all; the cost page explains what you would be paying for. The methodology detail lives on RdSAP 10 and EPC vs SAP.