Upgrading your home's energy efficiency can save hundreds of pounds a year on bills — but the upfront cost of insulation, heat pumps and solar panels puts many homeowners off. The good news is that several UK government schemes can cover part or all of the installation cost if you qualify. Here is a plain-English guide to every major grant available in 2025, who qualifies, and how to apply.
Great British Insulation Scheme (GBIS)
The Great British Insulation Scheme is the government's primary grant programme for home insulation. It runs alongside ECO4 and is managed by Ofgem.
Who qualifies:
- Properties with an EPC rating of D, E, F or G (the lower the rating, the more likely you are to qualify)
- Either in Council Tax bands A–D (England and Wales), OR in receipt of certain means-tested benefits regardless of council tax band
What it funds:
- Loft insulation (uninsulated or under-100mm top-up)
- Cavity wall insulation
- Solid wall insulation (internal or external)
- Underfloor insulation (in some cases)
How to apply: Visit trustmark.org.uk — registered installers under the scheme are listed there. You can also contact your energy supplier directly, as large suppliers are obligated to deliver a share of the scheme. The installer will assess your property's EPC and confirm eligibility.
Boiler Upgrade Scheme (BUS)
The Boiler Upgrade Scheme provides upfront capital grants towards low-carbon heating systems, paid directly to the installer and passed on as a discount to you.
Current grant levels (from April 2024):
- Air source heat pump: £7,500
- Ground source heat pump: £7,500
- Biomass boiler: £5,000 (in rural areas where alternatives are limited)
Key conditions:
- Property must have an existing boiler or direct electric heating
- Installer must be Ofgem-registered (MCS-certified) — check the Microgeneration Certification Scheme register
- Valid for England, Wales and Scotland
- The grant cannot be combined with ECO4 funding for the same measure
Heat pumps work best in well-insulated homes. If your EPC rating is poor, sort the insulation first — ideally via GBIS — before applying for BUS. For a prioritised guide to which energy upgrades to tackle first, see our home energy efficiency upgrades guide.
ECO4 (Energy Company Obligation, Phase 4)
ECO4 places a legal obligation on large energy suppliers to fund energy efficiency measures for fuel-poor and low-income households. It runs to March 2026.
Who qualifies:
- Households receiving income-based benefits (Universal Credit, Housing Benefit, Income Support, Pension Credit, etc.)
- Local Authority Flex (LA Flex): local councils can refer households not on benefits but in fuel poverty — this is a route for people just above benefit thresholds
What it can fund:
- Full insulation packages (loft, cavity, solid wall, underfloor)
- Heat pumps
- First-time central heating installations
- Solar panels in some cases
Contact your energy supplier's ECO team directly, or use the government's Simple Energy Advice service at simpleenergyadvice.org.uk to check eligibility and find local installers.
Home Upgrade Grant (HUG2)
The Home Upgrade Grant Phase 2 targets low-income households in England that are off the gas grid and have properties rated EPC E, F or G.
- Grants of up to £10,000 per property for insulation and low-carbon heating
- Delivered by local authorities — check your council's website for participation
- Must be a primary residence; landlords are not eligible via this route
- Available in England only — Scotland, Wales and Northern Ireland have separate schemes (Warmer Homes Scotland, Nest in Wales, Affordable Warmth NI)
Warm Home Discount
The Warm Home Discount provides a £150 rebate directly off your electricity bill. It is automatic for most qualifying households (Pension Credit recipients) and available to others who apply in summer each year.
This is not an installation grant, but it frees up cash that can go toward energy improvements.
Smart Export Guarantee (Solar)
If you install solar panels (with or without a battery), the Smart Export Guarantee (SEG) requires licensed energy suppliers to pay you for electricity you export to the grid. Rates vary by supplier but typically range from 3–15p per kWh. At an average export of 1,500 kWh/year, a household could earn £45–£225/year — not a grant, but a meaningful ongoing return on a solar investment.
Grant Amounts vs Typical Install Costs
| Measure | Typical Install Cost | Available Grant | Net Cost to Homeowner |
|---|---|---|---|
| Loft insulation (100mm+) | £300–£600 | GBIS: up to 100% if eligible | £0–£300 |
| Cavity wall insulation | £500–£1,500 | GBIS: up to 100% if eligible | £0–£750 |
| External solid wall insulation | £8,000–£20,000 | GBIS partial; ECO4 up to 100% | £0–£10,000 |
| Air source heat pump | £10,000–£15,000 | BUS: £7,500 | £2,500–£7,500 |
| Ground source heat pump | £15,000–£35,000 | BUS: £7,500 | £7,500–£27,500 |
| Solar PV (4kWp) | £5,000–£8,000 | No direct grant (SEG ongoing) | £5,000–£8,000 |
| Biomass boiler | £10,000–£20,000 | BUS: £5,000 | £5,000–£15,000 |
For a broader overview of every renovation grant and funding programme available in 2025 — including the Disabled Facilities Grant and Warm Homes Local Grant — see our complete renovation grants guide.
EPC Improvement Timeline Tips
- Get a fresh EPC first — older EPCs miss modern standards and may underestimate current performance. An EPC costs £60–£120.
- Do insulation before heating — a heat pump in a draughty home is inefficient. Loft and cavity wall first.
- Combine schemes where possible — GBIS and BUS can be used in sequence for the same property (insulation first, then heat pump).
- Check your local council — many councils have additional funding pots and can facilitate referrals to ECO4 or HUG2 faster than applying directly.
For a comparison of how period properties stack up against new builds on energy efficiency — and what retrofit really costs — see our retrofit vs new build energy efficiency guide. For a detailed breakdown of the SAP scoring system, MEES landlord obligations, and the 5 highest-impact improvements ranked by SAP points per £ spent, see our EPC rating UK guide. For a complete ranked guide to every EPC improvement measure — from the fabric-first sequence to what RdSAP assessors actually look for on the day — see our complete guide to improving your EPC rating in 2025.
Renovate Me can help you map out your energy efficiency improvements as part of a full renovation roadmap — upload your property details to see which measures would have the biggest EPC impact and which grants apply to your situation.
For the history behind the current scheme landscape — why the Green Deal failed, how its successor schemes differ, and the practical steps for combining ECO4, GBIS, and the Boiler Upgrade Scheme — see Green Deal Finance UK: History and What Has Replaced It.