What Does an
EPC Check Involve?

Step-by-step what happens during an EPC visit

An EPC site visit follows a standard process designed to capture enough data for the SAP or RdSAP software to calculate the rating accurately. The assessor cannot decide the rating themselves. They simply record data which the software then processes.

Before the visit. The assessor confirms the appointment plus typically asks for access to:

• All habitable rooms.
• The loft (or confirmation that there is no loft).
• The boiler plus heating controls.
• The hot water cylinder if separate from the boiler.
• External walls plus windows visible from outside.

During the visit (30 to 60 minutes). The assessor will:

• Measure every habitable room. Length, width plus ceiling height. They calculate total useful floor area for the SAP scoring. This is the largest single time component of the visit.
• Photograph the boiler. Manufacturer name, model number plus serial number. Used to look up boiler efficiency plus age in standard databases.
• Photograph the heating controls. Programmer, thermostat plus zone valves. Smart thermostats with zone control score better than basic thermostats.
• Inspect or confirm loft insulation. Depth of insulation plus type (mineral wool, fibreglass plus rigid board all score differently).
• Check the hot water cylinder. Insulated or uninsulated. Foam-insulated cylinders score better than unjacketed ones.
• Note window types plus frames. Single, double or triple glazing. Wooden, PVC or aluminium frames. Age of glazing if known.
• Check the lighting throughout. Number of low-energy fittings versus standard. LEDs throughout score best.
• Note construction type. Cavity walls, solid walls, timber frame, stone. Age of construction.
• Note any extensions or alterations. Different sections of the property may have different construction types plus heating systems.

What the assessor does NOT do:

• Open up walls or floors to inspect hidden insulation. Standard data entry assumptions are used where direct inspection is not possible.
• Test the boiler or controls beyond noting age plus type.
• Use thermal imaging cameras (rare for residential).
• Make subjective judgments about the property's energy performance. The software calculates the rating.
• Provide energy efficiency advice during the visit. Recommendations are produced by the software plus appear on the EPC.

Helpful records to have ready:

• Boiler installation date plus model number.
• Cavity wall insulation certificates if applicable.
• Loft insulation depth plus year fitted.
• Double glazing installation dates.
• Solar panel or heat pump installation certificates.
• Building regulations completion certificates for any extensions or alterations.

Providing these records helps the assessor capture all energy efficiency features plus typically results in a higher rating than the standard assumed values.

After the visit. The assessor enters all collected data into government-approved RdSAP software. The software calculates the rating automatically based on:

• Floor area plus property type.
• Construction type plus insulation levels.
• Heating system efficiency plus controls.
• Hot water provision.
• Glazing type plus area.
• Lighting energy efficiency.
• Air infiltration assumptions based on construction age.

EPC issue plus delivery. The completed EPC is:

• Lodged on the EPC Register at epcregister.com (typically within 24 hours of assessment).
• Emailed to the client as a PDF.
• Made publicly searchable on the register.
• Valid for 10 years from the date of issue.

If you disagree with the rating. EPCs are based on standard data entry assumptions plus may miss accurate features (like internal wall insulation hidden from inspection). To challenge an EPC, contact the original DEA. They can revisit if needed. If still unsatisfied, contact the assessor's accreditation scheme (Elmhurst, Stroma or Quidos) for an independent review.

Knowing what an EPC check involves helps you prepare for it. Our full EPC Ratings hub covers Energy Performance Certificates plus MEES regulations across UK homes plus rental properties.