Improving your EPC rating is mostly about fabric first — keeping heat in — then making the heating and controls more efficient. Here are the upgrades that give the best return, roughly in order of cost-effectiveness.
Best value improvements
| Improvement | Typical cost | Rating impact |
|---|---|---|
| Loft insulation (270mm+) | £300–£700 | Good — cheap and effective |
| Cavity wall insulation | £500–£1,500 | Good |
| LED lighting throughout | £50–£200 | Small but very cheap |
| Heating controls / smart thermostat | £100–£300 | Small–moderate |
| New condensing boiler | £2,000–£4,000 | Moderate |
| Solar panels | £4,000–£8,000 | Moderate–high |
| Air-source heat pump | £8,000–£14,000 (before grant) | High, esp. under the new metrics |
Grants that can fund the work
- Boiler Upgrade Scheme (England & Wales) — heat pump and biomass grants, no EPC needed to apply since April 2026.
- Warm Homes: Local Grant (England only) — free improvements for lower-income households in EPC D–G homes, delivered via local councils.
- ECO4 — the supplier-funded scheme runs until 31 December 2026, though most funding is already allocated. (The Great British Insulation Scheme closed on 31 March 2026.)
Getting from D to C
More than a third of English homes are still rated D — though band C is now the most common rating — and the jump from D to C is often achievable for £1,000–£4,000: typically loft insulation, cavity wall insulation and LED lighting, sometimes with better heating controls. Your EPC's recommendations page lists the specific measures and their estimated impact for your property — look yours up free on the official register.
A fabric-first order of work
- Insulate — loft, then cavity or solid walls. This reduces heat demand before you spend on heating.
- Draught-proof and upgrade glazing where cost-effective.
- Improve controls — a smart thermostat and zoning.
- Upgrade heating — a modern boiler or, ideally, a heat pump.
- Generate — solar PV (and battery) if the roof and budget allow.
Under the reformed Home Energy Model (from H2 2027), fabric performance and low-carbon heating carry even more weight — so insulation and a heat pump are strong future-proof choices. Landlords should note that qualifying spend counts toward the £10,000 cost cap from 1 October 2025, per the government's PRS response. Once the work is done, a fresh assessment captures it — see how to get a new EPC.
Frequently asked questions
Sources
- Energy Saving Trust — Roof and loft insulation advice
- Energy Saving Trust — Cavity wall insulation advice
- Energy Saving Trust — Solar panels advice
- Energy Saving Trust — Air source heat pumps advice
- GOV.UK — Apply for the Boiler Upgrade Scheme
- Energy Saving Trust — Boiler Upgrade Scheme explained (grant levels and £9,000 off-grid uplift)
- GOV.UK — Apply for the Warm Homes: Local Grant (England)
- GOV.UK — Extending the ECO4 end date: government response (ECO4 to 31 Dec 2026; GBIS closed 31 Mar 2026)
- GOV.UK — Improving the energy performance of privately rented homes: government response (£10,000 cap)
- GOV.UK — Reforms to the Energy Performance of Buildings regime (fabric-first metrics)
- GOV.UK — Find an energy certificate (your EPC's recommendations report)
About this guide
Researched and written by the EPC Certificate UK Editorial Team from official GOV.UK publications and regulatory guidance. Last reviewed 17 July 2026. For guidance only — not legal advice.