What mistakes cost people an EPC band?
The most expensive mistake is missing evidence. A blocked loft hatch, no cavity-fill certificate and no boiler paperwork all force the assessor to record conservative defaults. Between them they routinely cost a full band on a property that is genuinely better than its certificate says.
- Clear the loft hatch before the assessor arrives.
- Find cavity-fill, FENSA and boiler installation documents.
- Unlock garages, annexes and outbuildings.
- Tell the assessor about insulation that cannot be seen.
1. A loft hatch you cannot get through
The single most expensive mistake. If the assessor cannot see the insulation, RdSAP records the default depth for the property's age — typically far less than what is actually up there. Clear the hatch, move the boxes, and make sure there is a light.
2. No cavity-fill evidence
An insulated cavity with no paperwork is recorded as an uninsulated cavity. On inter-war stock that is often the difference between a D and a C on its own. Look for the installer's certificate, the grant-scheme paperwork, or anything from the guarantee agency. Failing that, tell the assessor where the drill holes are.
3. Missing boiler and glazing documents
Without the installation paperwork, the boiler is dated by its appearance and the glazing by the window style. Both defaults are conservative. A FENSA certificate and a boiler commissioning sheet take two minutes to find and are worth real points.
4. Locked outbuildings and annexes
Anything that forms part of the dwelling has to be assessed. A locked garage conversion or annexe either gets defaulted or holds up the whole survey. Find the keys before the appointment.
5. Assuming the assessor will take your word for it
They cannot. The method credits what can be seen or evidenced, and nothing else. Telling the assessor the walls were insulated in 2011 does not change the recorded value unless something supports it. This is not scepticism — it is how the calculation is required to work.
The five-minute fix
- Clear the loft hatch and check the light works
- Gather cavity, loft, FENSA and boiler paperwork into one folder
- Unlock every garage, outbuilding and annexe
- Find building-control certificates for extensions
- Note anything insulated that cannot be seen, and say so on the day
Together these routinely move a certificate a full band on a property that has not changed at all.
Book with the paperwork ready
Get a quote, or read what happens on the day on our domestic EPC page.
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