For Landlords

Understanding how to get an accurate EPC

For a residential EPC in England and Wales, an assessor can produce a compliant EPC from inspection alone — but the accuracy of the rating often depends heavily on the evidence the landlord can provide.

EPCs are visual only and record the information seen on the day of the inspection. Without evidence, assessors are legally required under RdSAP conventions to enter many items as “unknown” or assume lower/default specifications. That can reduce the EPC rating unnecessarily.

Best Practice for Landlords

Before the EPC visit: 

• Gather all certificates into one folder, email documents/photos beforehand.

• Ensure access to: Loft, boiler, meters, all rooms.

• Clear obstructions from loft hatches and heating equipment.

The Biggest EPC Rating Mistakes Landlords Make

• No boiler evidence – This can cost several SAP points. In most cases the assessor get the information needed from the boiler information tag - but not always.

• No insulation proof – Especially: cavity wall insulation, room-in-roof insulation, floor insulation.

• Boarding over loft insulation – Assessor cannot confirm depth. (LL could lift a few boards for inspection?)

• Missing heat pump documentation – Often results in conservative default assumptions.

• Old EPC assumptions remaining – A previous EPC may contain outdated construction assumptions (e.g. building or extension age…), that persist unless corrected with evidence.

Essential Information for an Accurate EPC

This is what an assessor would like to know.

You don’t necessarily have to provide it all, but at least you can see the scope of the data collection.

1. Property Address and Basic Details

• Full address including postcode.

• Property type: Detached, Semi-detached, Terrace, Flat/maisonette.

• Approximate construction age if known. (LL: Ideally the Title Deed showing a date for the property, building control sign off or planning approvals for extensions).

• Number of bedrooms.

• Heating System Information – This is one of the biggest influences on EPC scores.

2. Boiler Details

This allows the assessor to use exact efficiency data rather than generic assumptions.

• Boiler make, model and Gas Council Number (Assessors software can look up the type and efficiency of a particular boiler on their extensive database),

• Photos of boiler data plate and Gas Council Number (Done by assessor as a matter of course for audit purposes)

Useful documents:

• Boiler installation certificate

• Gas Safe certificate

• User manual

• Warranty paperwork

3. Heating Controls

Many landlords lose SAP points because advanced controls cannot be evidenced. Portable thermostats in particular are often hidden away, make sure they are obvious to the assessor. If you have user manuals with make and type this helps.

Assessors collect evidence of:

(LL: Where possible have user manuals nearby if make and model numbers are not obvious on the control).

• Programmable thermostat

• Smart controls

• Thermostatic radiator valves (TRVs)

• Zoned heating

• Weather compensation controls

• Heat emitter type (Radiators/Underfloor)

4. Loft Insulation

Assessors photograph roof type, insulation coverage, party wall construction, insulation type (joists or Rafters) and measure insulation depth. If insulation cannot be seen due to boarding or extensive storage, further evidence becomes important for an accurate result.

Useful:

(LL: Could lift a few boards in advance to allow assessors access to measure).

• Current recommended insulation (e.g. 270mm)

• Installation invoices. (Insulation certificate if done by a contractors, are sometimes stappled to a rafter close to the loft hatch).

• Building control documents -

5. Wall Insulation

Without evidence, walls may be recorded as uninsulated or assume a default value. Assessors do inspect wall types, measure wall thicknesses and look for visual evidence of internal and external wall installation.

Cavity wall insulation (CWI):

Where brick walls are exposed assessors can normally see a pattern of drill holes evidencing cavity wall infill, however its not always possible to prove due to rendering or repointing.

Useful documents:

• Guarantee certificate

• Installer invoice

• CIGA Guarantee - Replacements cost £60

External wall insulation (EWI):

Useful documents:

• Building control sign-off - EWI normally often requires approval, check local council planning website. Installers registered with a Competent Person Scheme can self-certify and often deal with the paperwork.

• Photos during works, specifications/invoices

Internal wall insulation (IWI):

• Photos during works, specifications/invoices

6. Floor Insulation

Floor insulation is frequently missed because it cannot be visually inspected.

Useful evidence includes:

• Renovation photos

• Building control paperwork

• Insulation invoices

• Construction drawings

7. Glazing Information – Windows & Doors

Assessors measure every window, note its area, facing direction and type and estimate the insulation gap and date. Additionally secondary glazing and insulated blinds are recorded. Often there are date stamps on the frames or on window insulating bars. However many older windows have no printed information.

Useful documents:

• FENSA certificate

• Installation invoice

• Window manufacturer details

• Approximate installation date

Especially important for: Triple glazing, new low-E double glazing, secondary glazing.

8. Solar PV Panels

Solar can materially improve EPC ratings.

Useful documents:

• MCS certificate

• Installation documents – solar system schematic

• Battery storage details

• Bill showing export payments

9. Solar Thermal / Heat Pumps

Heat pumps especially require accurate technical information.

Useful documents:

• Installation certificates

• Manufacturer/model

• Commissioning documents

• MCS paperwork

10. Low Energy Lighting

The assessor records fixed lighting only, but counts every bulb and type. This can slightly improve ratings.

Useful preparation:

• Ensure LED bulbs are installed in fixed fittings before inspection

• Replace halogens/incandescent where practical

11. Evidence of Extensions or Conversions

This helps determine: Construction age bands, insulation assumptions and wall types.

Useful documents:

• Building control approvals

• Planning documents

• Construction details

• Renovation photos

12. Flat-Specific Information

If applicable:

• Which floors are heated

• If communal corridors are heated

• Construction type

• Conversion date

13. Air Tightness

Since RdSAP 10 launched June 2026 assessors can now put measured air permeability results directly into the EPC . (Air is blown into the home, and then how quickly the air leaks out is measured).

Tests are not part of the standard EPC but can be commissioned for around £200-250. The potential uplift from a measured air tightness test is typically 1–3 EPC points, and in some cases the difference between one band and the next.

Important Point About Evidence

Under RdSAP rules, assessors cannot simply “take the landlord’s word for it” for many items.

Evidence usually needs to be:

• Good quality and able to demonstrate that any documents relates to the actual property being assessed.

• Documentary - Examples

  • Builders invoices to back up internal wall insulation claims

  • Cavity Wall insulation certificates

  • Fensa window/door certificates

  • MCS Certificates

  • Electricity bill to confirm tariff

• Photographic – ideally with a geotagging/time stamp photo app like solocator

(MORE DETAILS TO FOLLOW REGARDING PHOTO PROVIDED FROM LL)

• Visually confirmed onsite – Assessor needs proof the photo is of this property

**** If no proof exists, the assessor must use default assumptions. ****