The assessor needs to walk through the whole property, every room, the loft, boiler, hot water system, and meters, to collect the data required under RdSAP 10.

It’s non-invasive: no drilling, lifting floorboards, or opening up the boiler casing. They won’t carry out any work, but do need clear access to inspect walls, measure windows, check heating controls, and evidence any insulation that’s visible. If access to the loft hatch or boiler cupboard is blocked, they may have to make assumptions or arrange a second visit. Paperwork for solar PV, window installation dates, or cavity wall insulation is helpful if you have it.

Visits typically take 45 to 90 minutes. Read more about getting ready for your EPC.