Not every improvement earns its keep on an EPC. Some cheap measures move a rating by a band; some expensive ones barely register. This guide covers how the current score actually works, what moves it a lot, the traps that quietly cost points, and the value-for-money table to plan against.
Today's headline rating is a cost metric: it models the annual running cost of heating, hot water, lighting and ventilation per square metre, under standard assumed occupancy. An assessor collects data on the building fabric (walls, roof, floor, glazing, draught-proofing), the main heating system and its fuel, heating controls, hot water, lighting and any renewables, and the model turns them into a modelled running cost mapped to the A to G bands.
Because the elements interact inside a running-cost calculation rather than adding up like a scorecard, there is no fixed points tariff per measure. A poorly insulated home with a cheap, efficient heat source can outscore a well-insulated home on expensive electric panel heaters. Treat any published point ranges, including ours below, as rules of thumb, not promises, and model your own property first.
Because running cost drives everything, the heating system and its fuel can swing a rating dramatically. Assessors report replacing direct electric heating with an efficient gas condensing system lifting a property 30 to 40 points, mostly because the modelled cost of heat collapses. A heat pump scores well on the same logic, and better still under the incoming metrics. Wall insulation is the other heavy hitter, because walls are usually the largest heat-loss surface. Beyond those, returns taper.
Indicative ranges drawn from assessor guidance and retrofit analysis. Direction, not promises.
| Measure | Typical points | Indicative cost | Value |
|---|---|---|---|
| Loft insulation to 270mm | 5-15 | £300-£700 | Strong |
| Cavity wall insulation | 10-20 | £500-£1,500 | Strong |
| Heating controls / TRVs | 2-6 | £150-£600 | Strong |
| Draught-proofing | 1-4 | £100-£400 | Strong |
| LED lighting throughout | 1-3 | Under £100 | Strong |
| Cylinder insulation | 1-4 | £20-£150 | Strong |
| Floor insulation (suspended) | 3-6 | £500-£1,500 | Situational |
| New condensing boiler | Up to 40 from electric | £2,000-£3,500 | Situational |
| Solid wall insulation | 15-25 | £8,000-£15,000 | Situational |
| Solar PV | Meaningful | £5,000-£8,000 | Situational |
| Air source heat pump | Varies | £8,000-£13,000 | Situational |
| Double glazing (whole house) | 5-10 | £4,000-£8,000 | Weak for EPC alone |
The fastest, cheapest wins are usually the top six together: individually modest, they can shift a property 5 to 15 points, often enough to clear a band boundary if you're close. Double glazing is the classic disappointment: real money for a handful of points, better justified by comfort, noise or a wider refurbishment.
Insulation measures reduce fabric heat loss, so they count under both today's rating and the incoming fabric metric: the closest thing to a no-regrets investment. Boilers, heat pumps and controls act on the heating element and its modelled cost. Solar and storage feed renewables today and smart readiness under the new rules. Sequence fabric first, then heating, so any new system can be smaller and cheaper.
Don't overlook funding: cavity and loft insulation are frequently grant-funded in full or part, and the Boiler Upgrade Scheme supports heat pumps. Check what's available and who qualifies before paying yourself.
Before spending anything, have a good assessor model the specific changes required for your property under the current and new rules. The gap between a well-chosen measure and a poorly chosen one is the difference between clearing a band boundary and wasting four figures. It will be the single highest-return hour in the whole process. The deadlines, cap and exemptions are all in the cornerstone guide: EPC rules for landlords: what you need to do now.
Start with the facts on your property. Order an EPC for £95.
Point ranges and costs are indicative, from assessor guidance and retrofit analysis as at mid-2026. General guidance, not legal or financial advice.