What Happens During an EPC Assessment, and How Long It Takes

Most people booking an EPC have never had one done and are quietly wondering what they have signed up for. You are letting someone you have never met walk through every room of your house and put their head in your loft. So here is the whole thing, start to finish, with nothing left vague.

How long does an EPC assessment take?

Between 30 and 45 minutes for most homes. A large or unusual property can take up to an hour. I will tell you which when you book.

The visit is the short part. What takes the time afterwards is entering everything into the government calculation and checking it, which is why the certificate arrives afterwards, within 36 hours of the visit, rather than while I am standing there.

What does the assessor actually look at?

The building, not your belongings. Walls, roof, windows, heating, hot water, lighting and floor area — the things that decide how much energy the property needs.

In practice that means I will be looking at:

• Wall construction. Solid or cavity, and whether a cavity has been filled. This is usually the single biggest factor in the rating and it is the one people never expect.
• Loft insulation. I measure the depth, which means opening the hatch and putting a head and a torch through it.
• The heating system. Boiler make, model and age, and just as importantly the controls — room thermostat, programmer, thermostatic valves on the radiators.
• Hot water. Combi or cylinder, and if there is a cylinder, how well it is insulated.
• Windows and doors. Single, double or triple glazed, and roughly when they were fitted.
• Lighting. A count of the fixed light fittings and how many are low energy.
• Room dimensions. I measure the floor area, which means walking through every room with a laser measure.
• Extensions, conservatories and loft conversions. These are often built to a different standard from the original house and have to be recorded separately.

What I am not doing: judging your decorating, checking whether anything is safe, or inspecting for damp, structural problems or anything else a surveyor would look at. An EPC is an energy assessment and nothing more.

Do I need to be at home?

Someone over 18 needs to be there to let me in and stay while I work. It does not have to be you — a tenant, a family member or an agent with keys is fine.

If the property is empty and an agent is holding keys, that works too. Just tell me when you book so I can arrange collection.

What do you need access to?

Every room, the loft hatch, and the gas and electricity meters. If any of those are locked, blocked or behind a wardrobe, the assessment cannot be completed properly.

The loft is the one that catches people out. I am not going to climb into the loft and walk about, but I do need the hatch clear enough to open and get a light in. If it is under a pile of suitcases, moving them before I arrive saves us both ten minutes.

The meters matter because the type of meter tells the calculation what fuel the property actually uses. If yours are in a locked cupboard outside, have the key handy.

Do I need to tidy up or prepare anything?

No. The house does not need to be clean and nothing about the state of it changes the rating. Clearing the loft hatch and finding the meter key is genuinely all that helps.

One thing that does help, if you have it: paperwork for any work that has been done. Cavity wall insulation certificates, a boiler installation record, FENSA certificates for windows, or a solar panel commissioning document. Evidence like that lets me record what is actually there rather than what the calculation assumes by default — and the default assumption is usually the worse one.

Will you take photographs?

Yes. Photographs of the things that affect the rating — the boiler, the meters, the loft insulation, wall construction — are evidence for my accreditation body's audits.

They are for the assessment record and are not published with your certificate or shared with anyone else. If there is something you would rather I did not photograph, say so and I will work around it.

Can I ask you questions while you are there?

Please do. It is the most useful half hour you will get on the subject, and answering as I go costs nothing.

The questions I get asked most: why the rating is what it is, whether a particular improvement would be worth doing, what the neighbours are likely rated and why that differs, and whether the property meets the rules for letting. I would rather talk it through on the day than have you read a PDF afterwards and wonder.

What happens after you leave?

I enter everything into the government-approved calculation software, check it, and lodge the certificate on the national EPC register. It is then emailed to you.

Lodging is what makes the certificate official — an EPC that is not on the register does not count for a sale or a tenancy. Once it is lodged, anyone can look it up by postcode, and it stays valid for ten years.

How quickly do I get the certificate?

Within 36 hours of the visit, usually sooner. If you are up against a deadline with an agent or a solicitor, tell me and I will prioritise it.

What if the rating comes back lower than I hoped?

The certificate lists recommended improvements with estimated costs and savings, and I will go through which ones would actually move your band and which are not worth the money.

What I cannot do is adjust the number. The rating is a calculation from what is recorded at the property, and I record what is there. That is worth understanding rather than resenting: an inflated rating on a property you then let is a problem you have bought rather than avoided, and a rating that is too low costs you money on a sale. Getting it right is the whole job.

If you think something has been recorded wrongly — and it does happen, particularly with wall construction on older houses — tell me and I will check it against the evidence. That is a different thing from wanting a better number.

When can you come?

Seven days a week, from 7am to 10pm. Evenings and weekends are ordinary appointments here, at the same price as a Tuesday morning.

Most assessors work office hours, which means taking a day off or handing your keys to someone. You should not have to lose a day's pay to get a certificate that costs £65. I can usually offer something within a day or two, and if you ring while I am driving I will call you straight back.