What Happens During a Commercial EPC Assessment?
If you’ve booked — or are about to book — a commercial EPC (the official A-to-G energy-efficiency rating for a business or “non-domestic” building), it helps to know exactly what the assessment involves. It’s more straightforward than most people expect: a site visit by an accredited assessor, followed by some modelling and the certificate. This guide walks through the whole process step by step, including what you can do beforehand to make it quick and accurate.
Step 1: Booking and a few quick questions
When you get in touch, we’ll ask a few basics — the property type, rough floor area and postcode, and whether the building has air-conditioning — so we can confirm a fixed-fee quote and the right level of assessment. (Commercial EPCs are graded Level 3, 4 or 5 by how complex the heating, cooling and ventilation are; the building’s services decide which applies.) We then arrange a site visit at a time that suits you. For how pricing works, see our commercial EPC cost guide.
Step 2: What to have ready (this speeds it up)
You don’t need anything for us to do the job, but having a few things to hand makes the survey faster and the rating more accurate: – Floor plans (even rough ones) — they save the assessor measuring everything from scratch. – Details of the heating, cooling and ventilation systems — make, model or age if you have them. – Lighting information — whether it’s been upgraded to LED, and any controls fitted. – Any recent upgrades — new boiler, insulation, glazing, solar panels — with paperwork if available. – Access to all areas, including plant rooms, roof spaces and any separate zones.
If you don’t have these, that’s fine — we can record everything on site; it just takes a little longer.
Step 3: The site visit — what the assessor actually does
This is the core of it. On the day, the accredited non-domestic energy assessor carries out a non-intrusive survey — there’s no drilling, no disruption to trading, and no need to switch anything off. They will: – Measure the building and record floor areas and zones. – Record the construction — walls, roof, floors, windows and insulation, as far as they’re visible or evidenced. – Inspect the heating — type, age and efficiency of the system and its controls. – Check cooling and air-conditioning — whether fitted, and the type. – Note the ventilation — natural or mechanical, and how it’s controlled. – Record the lighting — fitting types (fluorescent, LED, etc.) and any sensors, timers or daylight controls. – Note hot-water provision and any renewables such as solar panels. – Take photos and evidence to support the assessment and satisfy the accreditation scheme’s audit requirements.
How long it takes depends on size and complexity — a small shop might be under an hour, a large multi-zone building considerably longer. The assessor records the building as it is; remember the EPC rates the building and its fixed systems, not how the occupier uses it, so day-to-day habits don’t affect the result.
Step 4: Modelling and producing the certificate
After the visit, the assessor enters everything into government-approved software — most commonly SBEM (the Simplified Building Energy Model) — which calculates the building’s energy performance and produces the A-to-G rating. Alongside the certificate you get a recommendations report suggesting how the rating could be improved, which is the starting point if you need to lift a poor score (see how to improve your commercial EPC rating).
Step 5: Lodgement on the register, and your copy
A commercial EPC only becomes valid once it’s lodged on the national EPC register — the official record that buyers, tenants and solicitors can check. We lodge it and send you your certificate with a fast turnaround after the visit. From the date of lodgement, the EPC is valid for 10 years. If you ever need to confirm it’s on the system, see our guide to how to check a commercial EPC on the register.
In short
One visit, no disruption, a clear rating and report, and a certificate lodged on the official register — usually within a few working days. Having plans and system details ready makes it quicker and more accurate, but it isn’t essential.
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Frequently asked questions
What happens during a commercial EPC survey?
An accredited assessor visits the building and records its construction, heating, cooling, ventilation, lighting and any renewables, then models it in approved software to produce the A-to-G rating. There’s no drilling or disruption.
How long does a commercial EPC assessment take?
The visit itself ranges from under an hour for a small, simple unit to several hours for a large, complex building. You then receive the certificate with a fast turnaround.
What does the assessor check?
The building fabric (walls, roof, windows, insulation), the heating, cooling and ventilation systems and their controls, the lighting, hot water and any on-site generation such as solar panels.
What do I need to provide for a commercial EPC?
Nothing essential, but floor plans, details of the heating and lighting, and access to all areas (including plant rooms and roof spaces) make the survey faster and more accurate.
Is the survey disruptive — do I need to close?
No. It’s a non-intrusive visual survey; there’s no drilling and no need to stop trading or switch systems off.
How soon do I get the certificate, and how long is it valid?
With a fast turnaround after the visit once it’s lodged on the register, and it’s then valid for 10 years.
Need commercial EPCs?
Fixed-fee, fast turnaround, accredited assessors.