What Does a Domestic Energy Assessor Check During an EPC?

A domestic energy assessor collects the property information needed to produce a domestic Energy Performance Certificate. The visit is usually straightforward, but knowing what the assessor needs to see can help avoid delays and make it easier to record genuine improvements accurately.

This guide explains what happens during a typical EPC assessment, what documents can help and what the assessor is—and is not—checking.

What is a domestic energy assessor?

A domestic energy assessor is trained and accredited to assess homes for Energy Performance Certificates through an approved accreditation scheme. The assessor records the property’s fixed energy-related characteristics and uses the approved methodology to produce the EPC.

The assessment is not a homebuyer survey and it is not a safety inspection. Its purpose is to create the energy-performance certificate and recommendations.

What will the assessor look at?

The exact inspection depends on the property, but the assessor may record:

• property type, age-related construction and dimensions;
• wall, roof and floor construction where relevant;
• insulation that is visible or supported by acceptable evidence;
• windows and glazing;
• the main heating system and secondary heating where applicable;
• heating controls;
• hot-water system and cylinder details;
• fixed lighting;
• renewable technologies or other features recognised by the methodology.

Photographs and notes may be taken as evidence for the assessment and accreditation audit requirements.

Does the assessor need to access the loft?

Where a loft is relevant and safely accessible, the assessor may need to inspect it to record roof construction or insulation. Make sure the loft hatch is accessible and the route is not blocked. The assessor is not expected to enter an unsafe space.

Does the assessor inspect the boiler?

The heating system is an important part of the EPC, so the assessor needs to identify relevant equipment and controls. Keep the boiler or other main heating appliance accessible. If the model information is difficult to see, service documents can sometimes help identify the system.

What documents should you prepare?

Documents are especially useful for features that cannot be seen. Depending on the property, helpful evidence may include:

• building-control completion documents for extensions or conversions;
• insulation installation records;
• window installation certificates or specifications;
• boiler or heating-system documentation;
• renewable-technology commissioning paperwork;
• plans or specifications relevant to concealed construction.

Do not worry if you do not have every document. The assessor will use the evidence available and the methodology’s conventions. But if you have proof of significant improvements, make it available before or during the visit.

How long does an EPC assessment take?

There is no single time that applies to every property. The visit depends on the size, complexity, access and amount of information that needs to be recorded. A small flat is different from a large or unusual house.

When requesting a quote, provide an accurate property type and approximate size where possible. That helps the assessor understand the likely scope.

Do you need to tidy the whole property?

No special presentation is required, but the assessor needs safe access to relevant areas. Clear obstructions around the boiler, heating controls, hot-water cylinder, loft hatch and meters. Make sure rooms can be entered and windows or relevant building elements can be viewed.

What the assessor does not do

An EPC visit is not a structural survey, valuation, gas-safety inspection or electrical test. The assessor does not normally dismantle the building to prove concealed construction. That is why documentary evidence can be important.

What happens after the visit?

The recorded data is entered into the approved assessment software and the certificate is lodged through the accreditation process. The EPC then shows the current rating, potential rating and recommendations.

For homes in England and Wales, the official certificate can be found on the government register once lodged. A domestic EPC is generally valid for 10 years unless a newer one is produced.

How to prepare in 10 minutes

1. Check whether a valid EPC already exists.
2. Confirm the correct property address and postcode.
3. Clear access to the heating system and controls.
4. Make the loft hatch accessible if there is one.
5. Gather paperwork for insulation, extensions, glazing and heating upgrades.
6. Tell the assessor about access restrictions before the appointment.

Book the right assessment

If you only need an Energy Performance Certificate, a domestic EPC assessment is the appropriate route. If you are planning a coordinated package of energy improvements, you may also want to consider a retrofit assessment.

To arrange an EPC, send the property postcode and details. If you are unsure whether a valid certificate exists, do an EPC rating check first.