Hot water cylinder jacket
Cheapest measure on the list. Fits in ten minutes.
- Typical cost
- £20 – £40
- Saving a year
- £35
Official answer
What does an EPC measure in a home?
An EPC assessment records the building's construction and energy features, including walls, roof, floor, windows, heating, hot water, lighting and renewable technology. Standardised assumptions are used to produce the A-to-G rating and recommendations, so the result is not the same as measuring one household's actual energy bills.
Guidance checked 10 September 2026. Exact sources are listed below.
Your EPC, explained line by line
Ten things are measured in your home, and each one moves your score in a different way. Here is what every line means, what a band is worth in real money, and the cheapest route to a better one.
What is measured — and how much each part counts
The assessor works to a fixed government methodology. Tap any line to see what they look at and how to score better on it.
What the assessor measures
Construction type (solid, cavity, timber frame), thickness, and whether the cavity or internal face has been insulated.
Why it moves your score
Walls are the largest surface losing heat in most homes, so they carry more of the score than anything else in the fabric.
Best value improvement
Fill an unfilled cavity — typically £500–£1,500 and usually worth a full band.
Have this ready on the day
Cavity insulation guarantee (CIGA), installer invoice, or a grant/ECO completion certificate.
Where a feature cannot be seen or evidenced, the methodology scores the default for your property's age — almost always the worst case. Ten minutes of paperwork can be worth a whole band.
What a band is actually worth
Bands are not just letters — they are the difference in what the home costs to run every year.
Typical difference
£1,070 a year
Moving from band E to band C is worth roughly £1,070 a year on a typical three-bedroom home — about £10,700 across the ten years the certificate lasts.
Band E running cost
£2,050/yr
Over the certificate's 10 years
£10,700
Illustrative figures for a typical three-bedroom home, based on the cost bands published with the government's energy efficiency statistics. Your own certificate prints the figures for your property.
The A–G scale, as it appears on your certificate
92–100A
Very efficient — lowest running costs
81–91B
Efficient, typical of a good new build
69–80C
PotentialAbove average for UK homes
55–68D
The most common rating in the UK
39–54E
NowMinimum standard to let a home in England & Wales
21–38F
Below the letting standard — improvements needed
1–20G
Least efficient — highest running costs
- Band C (69–80) — Above average for UK homes
- Band E (39–54) — Minimum standard to let a home in England & Wales
Why an EPC is worth having
Beyond the legal requirement. Pick who you are and see what applies.
It is the law before you market
Selling or letting in England, Wales or Northern Ireland requires a valid EPC commissioned before the property is advertised. Trading standards can fine £200 for a home and up to £5,000 for a rented property.
You cannot let below band E
Rented homes must reach band E unless a valid exemption is registered on the PRS Exemptions Register. Letting below it risks a penalty of up to £5,000 per property.
Buyers price it in
The rating is displayed on every portal listing. A poor band invites offers below asking on the assumption of expensive works; a good one removes the argument.
Green mortgage and cashback rates
Most large lenders now offer a reduced rate or cashback where the certificate shows band A or B, and use the EPC as the proof.
A costed plan for your bills
The recommendation report lists what to do, in what order, with indicative cost and annual saving for each measure — a free improvement plan for your home.
It unlocks grants
ECO4, Great British Insulation Scheme and most council schemes use your EPC band to decide eligibility. No certificate, no application.
Evidence for the sale pack
Conveyancers ask for it at the start. Having it lodged before you list removes one of the most common causes of early delay.
A ten-year record
Once lodged it sits on the public register for ten years, which is proof of the property's condition on that date for any future dispute.
The cheapest ways to move up
The standard measures printed on recommendation reports, with typical published costs and savings — cheapest first.
+1 to +3 points
Low energy lighting throughout
Assessors record the share of fixed low-energy lights, so swap them before the visit.
- Typical cost
- £30 – £80
- Saving a year
- £45
Loft insulation to 270mm
The single cheapest win in most older houses. A day's work and no disruption.
- Typical cost
- £300 – £600
- Saving a year
- £170
Cavity wall insulation
For homes built roughly 1930–1995 with an unfilled cavity.
- Typical cost
- £500 – £1,500
- Saving a year
- £235
Suspended floor insulation
Worth doing while floorboards are up for other work.
- Typical cost
- £800 – £1,200
- Saving a year
- £90
Condensing boiler with modern controls
The biggest single jump for homes still on an old non-condensing boiler.
- Typical cost
- £2,200 – £3,500
- Saving a year
- £320
Double or secondary glazing
Slow to pay back on bills alone, but it lifts comfort and the score together.
- Typical cost
- £3,000 – £7,000
- Saving a year
- £155
Solar photovoltaic panels
The strongest single measure for pushing a D or E home up to a B.
- Typical cost
- £5,000 – £8,000
- Saving a year
- £430
| Measure | Typical cost | Saving a year | Score impact |
|---|---|---|---|
Hot water cylinder jacket Cheapest measure on the list. Fits in ten minutes. | £20 – £40 | £35 | +1 to +3 points |
Low energy lighting throughout Assessors record the share of fixed low-energy lights, so swap them before the visit. | £30 – £80 | £45 | +1 to +2 points |
Loft insulation to 270mm The single cheapest win in most older houses. A day's work and no disruption. | £300 – £600 | £170 | Up to +1 band |
Cavity wall insulation For homes built roughly 1930–1995 with an unfilled cavity. | £500 – £1,500 | £235 | +1 band |
Suspended floor insulation Worth doing while floorboards are up for other work. | £800 – £1,200 | £90 | +2 to +4 points |
Condensing boiler with modern controls The biggest single jump for homes still on an old non-condensing boiler. | £2,200 – £3,500 | £320 | +1 to +2 bands |
Double or secondary glazing Slow to pay back on bills alone, but it lifts comfort and the score together. | £3,000 – £7,000 | £155 | +1 band |
Solar photovoltaic panels The strongest single measure for pushing a D or E home up to a B. | £5,000 – £8,000 | £430 | +1 to +2 bands |
Indicative published figures for a typical home, not a promise for yours. Your certificate lists the measures that actually apply to your property.
Be ready for the assessor
Anything that cannot be seen or evidenced is scored as the worst case for your property's age. Tick these off before the visit.
Worth ten minutes before the assessor arrives
0 of 9 done — each one stops the software assuming the worst case.
0%
What you get with every booking
One price, and the whole package.
The official certificate
Lodged on the government EPC register within 48 hours, with your certificate number and a permanent public link.
Your current and potential score
The A–G band you have today, and the band your home could reach if the recommendations were carried out.
Every line explained
We turn the assessor's findings into plain English — what was measured, what it means, and what to do next.
A costed improvement plan
The measures that apply to your home, cheapest first, with indicative cost, annual saving and the bands each one is worth.
Ten years of reminders
We watch the expiry date and tell you at 90, 30 and 7 days, so a certificate never lapses mid-sale.
It joins your property record
The rating flows straight into your HomeCheck report, sale pack and property profile — no re-typing.
- Protected by Cloudflare
- Encrypted in transit
- UK GDPR compliant
- Official sources only
Still have questions? We're here to help.
EPC from £79
Lodged in 48 hours
Answer library
People also ask
Does an EPC use my actual energy bills?
No. The rating uses a standardised methodology so properties can be compared independently of household size and behaviour.
Will the assessor need access to every room?
The assessor needs sufficient access to inspect and record relevant construction, heating, glazing, lighting and insulation evidence.
Are improvement savings guaranteed?
No. Certificate recommendations use standard assumptions. Actual costs and savings depend on the building, installation and household use.
Official sources
Source guidance verified 10 September 2026. Availability and effective dates remain subject to the linked official publication.