How this calculator estimates your rating
An EPC score runs from 1 to 100 and is calculated from the modelled cost of heating, hot water and lighting per square metre. Our estimate starts from a base score for your property's age, because age is the strongest single predictor of a rating: in the English Housing Survey the mean SAP rating for English dwellings was 68 points in 2024, and 27% of homes built before 1919 reached bands A to C against 55% to 94% of homes built after 1944. It then adds or subtracts points for your walls, loft, glazing, heating, solar panels and lighting, using the same point values as the improvement list below. It is a rough guide from a simple points model, not an assessment. For a typical home of each age it lands close to the average ratings in the English Housing Survey, but it has not been checked home by home against lodged certificates, so treat the band as a starting point. It is not an EPC: a certificate needs a domestic energy assessor, costs about £65 to £95 for a typical house and lasts ten years. Read how EPC points are calculated or see what each band pays in bills.
How is an EPC calculated?
It is a model, not a reading of your bills. An assessor records the home and the government's SAP model turns its modelled running cost per square metre into a score from 1 to 100, banded A to G.
What homes of your age typically rate: EPC rating by house age.
Read the detail
An Energy Performance Certificate is not a reading of the energy you actually used last year. It is a model. A domestic energy assessor records the fabric and services of the property, and the government's Standard Assessment Procedure estimates what the home would cost to run under a standard heating pattern, expressed per square metre of floor area.
The rating covers regulated energy only: space heating, water heating, cooling, ventilation and lighting. Cooking and appliances are excluded by design, which is why two households in identical homes can run up very different bills and still sit in the same band. The calculation also uses fixed fuel prices rather than live tariffs, so your rating does not move when the price cap does.
Which methodology is used
Existing homes are assessed using RdSAP, the reduced data version of SAP that lets an assessor work from a site visit rather than construction drawings. GOV.UK lists SAP 10.3 and RdSAP 10.0.1 as the current approved versions. The government plans to replace SAP with the Home Energy Model, but GOV.UK states that SAP 10.3 is currently the sole approved methodology and gives no start date, so every EPC issued today still comes from SAP. Separately, reformed EPCs will carry four headline metrics covering energy cost, fabric performance, the heating system and smart readiness, with the existing A to G efficiency rating kept alongside them as a legacy metric. In March 2026 the government moved their launch to the second half of 2027.
EPC rating calculation: turning points into a band
The model returns a single score between 1 and 100, where 1 is extremely poor efficiency and 100 represents a home with no net annual energy cost. That score is then placed in one of seven bands, shown in the chart above. The bands are not equal widths, so a single point is worth more at some thresholds than others. Going from 68 to 69 lifts you out of D and into C. Going from 60 to 68 is eight points of work that leaves you in band D throughout.
That is why this calculator ranks upgrades by cost per point rather than by headline saving. If you sit two points below a band boundary, £100 to £300 of LED lighting can move your band, while about £4,800 of new windows spent mid-band may not. For how each element is weighted, read how EPC points are calculated.
Where most homes land
In 2024 the average SAP rating for English dwellings was 68 points, up from 45 points in 1996. Band C is now the most common rating, covering 49% of owner occupied homes, 48% of privately rented homes and 69% of social rented homes. Across the whole stock, 56% of dwellings sit in bands A to C, 35% in band D and 9% in bands E to G. Age remains the strongest single predictor: 27% of homes built before 1919 reach bands A to C, against 55% to 94% of homes built after 1944.
How to improve your EPC rating in 2026
Start with what your home lacks. With under 100mm in the loft, insulating it costs about £750 for about 7 points; with good insulation and an old gas boiler, a heat pump adds about 12.
Read the detail
Your EPC (Energy Performance Certificate) rates your home's energy efficiency on a scale of A (most efficient) to G (least efficient). Band C is now the most common rating in England, and band D the next most common, so most homes are working from the middle of the scale rather than the bottom. Improving your rating can cut energy bills, and it is increasingly required by law for rental properties.
The most cost-effective improvements depend on what your property already has. A home with under 100mm in the loft should usually start there: it costs about £750 and adds about 7 points in our model. A home that already has good insulation but an old gas boiler gains about 8 points from a new condensing boiler and about 12 from a heat pump.
EPC improvements ranked by cost-effectiveness
Cheapest per point: LED lighting and smart controls. Loft insulation in a bare loft costs about £750 for about 7 points, cavity walls about £2,200 for about 8, and solid wall insulation is the dearest per point.
Read the detail
Here are the typical improvements, cheapest per point first, with the points this calculator gives each one. Insulation and window costs are Energy Saving Trust 2026 figures, heat pump costs are Boiler Upgrade Scheme medians, the boiler is the DESNZ average, and the rest are typical installed prices. Grants can make insulation free, which changes the order.
- LED lighting throughout: £100 to £300, adds 2 or 3 points. Simple DIY improvement.
- Smart heating controls: £150 to £400, adds about 3 points.
- Loft insulation to 270mm: about £750 in a bare loft, or about £600 to top up from 120mm, and adds about 7 points if you have under 100mm now. Often available free through grants. Calculate your savings.
- Cavity wall insulation: about £2,200 for a typical home, adds about 8 points. Check if your walls are suitable.
- New condensing gas boiler: about £3,500, the DESNZ average including VAT, and adds about 8 points when it replaces a gas boiler over 15 years old. At about £440 a point that is close to a heat pump replacing the same boiler after the grant, so which comes first depends on the home.
- Heat pump: a median £12,700 installed for a 3 bed semi, before the £7,500 grant (£9,000 when it replaces oil or LPG). Adds about 12 points replacing a gas boiler over 15 years old and 20 replacing electric heating, but only 4 replacing a newer gas boiler. Calculate your costs, then check what it costs to run and which tariff makes the saving.
- Solar panels: £5,000 to £7,000 for a 4 kW system, adds about 8 points. Calculate your ROI.
- Double glazing: about £4,800 for A-rated windows in a semi-detached house, adds about 6 points replacing single glazing. Expensive per point, but improves comfort significantly.
- Solid wall insulation: about £12,000 done internally for a typical 3 bed semi, or £15,000 externally, adds about 10 points. The most expensive per point, but often the only large gain for a solid walled home. Check potential savings.
EPC requirements for landlords
Band E today, a new standard from 1 October 2030. The maximum fine then rises to £30,000 per property per breach, and landlords must spend up to £10,000 per property on qualifying improvements.
Read the detail
Rental properties in England and Wales must currently have a minimum EPC rating of Band E. Under the rules in force today, a local authority can fine a landlord up to £5,000 in total per property.
That changes on 1 October 2030. In its January 2026 response to the privately rented homes consultation, the government confirmed a single compliance date for all tenancies, dropping the earlier plan to phase the standard in for new tenancies first. Homes will need to meet a primary standard on the fabric performance metric plus a secondary standard on either the heating system metric or the smart readiness metric, whichever the landlord prefers. The maximum fine rises to £30,000 per property per breach.
Landlords will be required to spend up to £10,000 per property on qualifying improvements. If you reach that cap and the property still falls short, you can register a cost cap exemption, which lasts 10 years. Most other exemptions last five years. Improving gradually costs less than rushing at the deadline, which is what the cost-per-point ranking above is for.
Frequently asked questions
How is an EPC calculated?
An assessor records the property's walls, roof, floors, windows, heating, hot water, lighting and any renewables, then the government's Standard Assessment Procedure models what the home would cost to run under a standard heating pattern. The result is a score from 1 to 100, which is then banded A to G. It counts space heating, water heating, cooling, ventilation and lighting only, so cooking and appliances do not affect it.
Is this Energy Performance Certificate calculator free?
Yes. It is free to use, runs in your browser and needs no sign-up or email address. It gives you an estimate rather than a certificate: only an accredited domestic energy assessor can issue an EPC, and a certificate is valid for 10 years.
What is the minimum EPC rating for landlords in 2026?
Band E. That is the standard in force today, backed by fines of up to £5,000 per property. From 1 October 2030 every privately rented home in England and Wales must meet a Band C equivalent standard, and the maximum fine rises to £30,000 per property per breach.
How accurate is the EPC estimate?
It is a rough guide from a simple points model, not an assessment. For a typical home of each age it lands close to the average ratings in the English Housing Survey 2024, for example 60 points for a Victorian terrace against a survey average of 60.3, but we have not checked it home by home against lodged certificates, so we do not quote an accuracy for your home. It starts from a base score for homes of your age and adjusts it for your walls, loft, glazing, heating, solar panels and lighting. Treat the band as a starting point and check the register for your real rating: only a domestic energy assessor can issue an EPC.
How much does it cost to improve an EPC rating?
Costs vary widely. In our points model, loft insulation in a bare loft (about £750) adds about 7 points and cavity wall insulation (about £2,200) about 8, at Energy Saving Trust costs. A heat pump costs a median £12,700 installed for a 3 bed semi before the £7,500 grant (£9,000 when it replaces oil or LPG), and adds 4 to 20 points depending on the heating it replaces. Internal solid wall insulation costs about £12,000 and adds about 10. Many improvements qualify for government grants.
What improves an EPC rating the most?
In our points model the biggest single gains come from the heating: a heat pump adds about 20 points when it replaces electric heating and about 12 when it replaces a gas boiler over 15 years old. Solid wall insulation adds about 10, and cavity wall insulation, solar panels and a new condensing boiler about 8 each. Loft insulation adds about 7. The best approach depends on what your property already has.
Does a new boiler improve EPC rating?
Yes. Replacing a gas boiler over 15 years old with a modern condensing boiler adds about 8 points in our model. A heat pump adds most when it replaces an old boiler, oil, LPG or electric heating, and only a few points when it replaces a modern gas boiler. That is because the rating is based on the modelled cost of running the home, not on whether the heat is renewable. See our boiler vs heat pump comparison for the full analysis.