The key difference is that GBIS (Great British Insulation Scheme) targets specific insulation measures for a broader income group, while ECO4 is a deeper whole-house fuel-poverty scheme for low-income and vulnerable households. Both are government energy-efficiency obligations on energy suppliers, but their eligibility, scope, and delivery models differ significantly. Ofgem states ECO4 is built to deliver “a whole-house approach” to energy efficiency, whereas GBIS focuses on single insulation measures (Ofgem, 2026).
- The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing.
- ECO4 targets EPC bands E-G; GBIS is for Council Tax bands A-D in England.
The deciding variable is household income and the type of property. ECO4 is for homeowners or private tenants in receipt of means-tested benefits, such as Universal Credit or Pension Credit, and requires a minimum Energy Performance Certificate (EPC) rating of E, F, or G. GBIS is open to a wider group: households in Council Tax bands A–D in England, regardless of income, or those receiving the same benefits as ECO4. If you are on benefits, ECO4 offers a broader range of measures and a full retrofit assessment. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing.
Eligibility and income thresholds differ
ECO4 is strictly for households on qualifying benefits, with no alternative route. The Department for Energy Security and Net Zero confirms that ECO4 eligibility is “limited to low-income and vulnerable households” (GOV.UK, 2026). The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. This makes GBIS accessible to working households who do not claim benefits but live in less efficient homes. Both schemes require the property to have a suitable cavity or loft space for the proposed measure.
Scope of measures and whole-house approach
ECO4 mandates a whole-house retrofit plan, typically including a combination of insulation, heating upgrades, and renewable technologies. The Energy Saving Trust notes that ECO4 aims to treat the home as a system, addressing multiple fabric and heating improvements together (Energy Saving Trust, 2026). The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. If your home needs more than insulation, ECO4 is the appropriate route. For a straightforward insulation-only upgrade, GBIS may be quicker and simpler to access.
Funding and installation process
Both schemes are funded by energy suppliers and delivered through approved installers. Ofgem oversees compliance for both, but the application process differs. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. For ECO4, a full retrofit assessment is required, often conducted by a TrustMark-registered installer. The cost of measures under both schemes is fully funded for eligible households, with no upfront payment. TrustMark states that all work under ECO4 and GBIS must be carried out by certified installers to ensure quality (TrustMark, 2026). If you are unsure which scheme applies, check your benefit status and Council Tax band first, then contact a local approved installer for guidance.
A worked example
A typical 1930s semi-detached house in Manchester with an EPC rating of F qualifies for ECO4 if the household receives Pension Credit. The whole-house assessment identifies cavity wall insulation, loft insulation to 300mm, a new gas boiler, and smart heating controls as the recommended measures. Under ECO4, the total cost of these works could reach £14,000, but the energy supplier obligation covers 100% of the cost for eligible households. The annual energy saving from the combined fabric and heating upgrades is estimated at £1,200 based on Energy Saving Trust data. Over 25 years, the household avoids £30,000 in energy bills. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. Glazing is standard-rated for VAT at 20%. The zero rate for energy-saving materials covers insulation, heat pumps and solar panels; HMRC names secondary and double glazing as excluded (VAT Notice 708/6).
| Item | Figure |
|---|---|
| Upfront cost after grants | £0 |
| Yearly savings | £1,200 |
| Payback period | Immediate (zero cost) |
| 25-year lifetime savings | £30,000 |
What homeowners often get wrong
The most common mistake is assuming GBIS and ECO4 are interchangeable schemes that can be applied for in the same way. Here are three misunderstandings that cost homeowners time and money.
- The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. Homeowners who expect a full retrofit under GBIS are left with gaps in their home’s performance and miss out on the whole-house savings ECO4 delivers.
- Thinking ECO4 is available to any low-income household ECO4 eligibility requires receipt of specific means-tested benefits like Universal Credit or Pension Credit. Households with low income but no qualifying benefit cannot access ECO4 and often waste time applying, then face delays or rejection.
- Believing you can choose your own installer Both schemes require installation by an Ofgem-approved or TrustMark-registered contractor. Homeowners who hire a local builder without checking accreditation void the grant eligibility and risk paying the full £5,000–£15,000 cost themselves.
Quick reference
- ECO4 covers whole-house improvements including insulation, heating, and renewables for households on means-tested benefits with an EPC rating of E, F, or G.
- The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing.
- Both schemes are delivered by energy suppliers under obligations set by Ofgem, meaning you cannot apply directly to the government.
- The average ECO4 installation saves £1,200 per year on heating bills, while a single GBIS measure saves around £300 annually according to Energy Saving Trust figures.
- Installers must be TrustMark registered and MCS certified for heat pumps under ECO4 to avoid invalidating your grant or warranty.
Frequently Asked Questions
No, ECO4 is strictly for households on qualifying means-tested benefits such as Universal Credit or Pension Credit. GBIS is the alternative for those not on benefits but in Council Tax bands A-D.
GBIS has no income limit for the Council Tax band route (bands A-D in England). Ofgem confirms that for the benefit-based route, the same income thresholds as ECO4 apply.
GBIS is limited to single insulation measures like cavity wall or loft insulation.
