It is a survey of the building, not your habits
An EPC measures the property, not the people in it. How often you run the heating makes no difference to the score.
What gets recorded
- Dimensions, every room is measured to calculate floor area and heat loss surfaces.
- Walls, construction type and any insulation, established by age, drilling records or visual evidence.
- Loft and roof, insulation depth is physically measured where accessible.
- Glazing, single, double or triple, and approximate installation date.
- Heating, boiler make and model, controls, thermostats and any secondary heating.
- Hot water and lighting, cylinder insulation and the proportion of low energy bulbs.
Evidence matters
Assessors must record what they can verify. If you have cavity wall insulation or a newer boiler, having the paperwork ready can measurably improve your rating, because unverified improvements are scored on default assumptions.
How long it takes
Most domestic assessments take 30 to 60 minutes on site.