EPC Band Comparison Calculator

EPC bands run from A to G on a points scale, and each one describes a recognisable kind of property. A, at 92 and above, belongs to new builds and homes retrofitted to near-passive standards. B, at 81 to 91, covers modern houses with insulation and a condensing boiler, while C, at 69 to 80, takes in most newer UK builds and well-maintained older homes. D, at 55 to 68, is the UK average, typically a post-1960s house with cavity wall insulation. E, at 39 to 54, usually means solid walls or an old boiler, and F at 21 to 38 and G at 1 to 20 are generally pre-1920s solid-wall properties with no retrofit at all.

Comparing EPC ratings between properties helps you understand the relative energy costs and efficiency of different homes. A property rated Band C typically has annual energy costs £300 to £600 less than a Band D property, and £600 to £1,200 less than a Band E property, though the exact savings depend on property size, heating system and local energy prices. Around 39% of UK homes are rated D or below and 5% sit at F or G. London performs best because of its higher new-build ratio, while rural Wales and south-west England fare worst thanks to older stone properties. Off-grid homes on oil or LPG land in the D to E range, and listed buildings are often F or G, exempt from many regulations.

When buying a property, the EPC shows both the current rating and the potential rating if recommended improvements are made. The gap between the two indicates how much room there is for improvement, and properties with a large gap often offer the best value because energy costs can be reduced significantly through upgrades. This calculator compares the EPC ratings and estimated energy costs of up to three properties side by side, showing the annual cost difference, the likely cost of upgrades to reach the potential rating and the estimated payback period for each improvement.

The route from a poor rating to a decent one is fairly standard. Loft insulation costs £200 to £900 and repays itself in 1 to 3 years, which puts it first on almost every list. Cavity wall insulation follows at £400 to £1,500, then double glazing at £4,000 to £8,000, then a new boiler or a heat pump. Solid-wall properties are the awkward case, because external wall insulation runs £8k to £20k and takes 12 to 25 years to pay back. Moving from D up to B saves £400 to £700 a year, and dragging an F-rated house to C saves £700 to £1,500.

Individual measures move the score by fairly predictable amounts. LED bulbs throughout are worth 1 to 2 points, a hot water tank jacket 1 point, a smart thermostat 2 to 3, and 270mm of loft insulation 3 to 7. Cavity wall insulation and double glazing each add 5 to 10 points, a condensing boiler 3 to 7, and solid wall insulation 15 to 25, the largest single improvement available. Installing a heat pump removes the gas dependency and typically jumps 2 to 3 bands, helped along by the £7,500 Boiler Upgrade Scheme grant. The government target is every UK home at EPC C by 2030, which implies roughly £14k of retrofit on each F and G property.

Rating feeds into value as well as running costs. Rightmove research from 2024 put each band improvement at about 3 to 6% on the price of a UK property, and a C-rated home carries a 6 to 12% premium over a G-rated one. Landlords face something firmer than a premium, since the Minimum Energy Efficiency Standards will require every privately rented home to reach EPC C by 1 October 2030, confirmed in January 2026, with landlords' spending capped at £10,000 per property. Letting an F or G rated property has been illegal since 2018 apart from limited exemptions, and councils can fine landlords who let non-compliant homes.