The short answer on whether you can combine energy grants in 2026
Most government energy grants in England, Scotland, and Wales cannot be stacked for the same measure, such as using two grants to pay for one boiler. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing.
The Energy Company Obligation (ECO4) and the Great British Insulation Scheme (GBIS) are the two main grants that can sometimes be combined, but only for different property types or different measures within the same property (GOV.UK, 2026). The Boiler Upgrade Scheme (BUS) explicitly prohibits being used alongside ECO4 or GBIS for the same heating system upgrade (GOV.UK, 2026). You must meet the eligibility criteria for each grant individually.
Quick numbers – typical combined grant values in 2026
The table below shows the maximum values and combination rules for the main UK energy grants available in 2026. All figures are from official government sources.
| Grant name | Typical maximum value (GBP) | Eligible measures | Can it be combined with other grants? |
|---|---|---|---|
| Great British Insulation Scheme (GBIS) | £1,500 | Loft, cavity wall, solid wall insulation | Yes, with ECO4 for different measures |
| Energy Company Obligation (ECO4) | £10,000 | Insulation, heating controls, first-time central heating | Yes, with GBIS for different measures |
| Boiler Upgrade Scheme (BUS) | £7,500 | Air source heat pump, ground source heat pump | No, cannot combine with ECO4 or GBIS for the same heating system |
| Home Upgrade Grant (HUG2) | £30,000 | Insulation, heat pumps, solar PV | No, for off-gas-grid homes only; cannot combine with ECO4 |
Source: DESNZ, 2026; Ofgem, 2026; GOV.UK, 2026.
Which two grants are most commonly combined in practice
ECO4 and GBIS are the most commonly combined grants in 2026. You can use them together for different measures in the same property. For example, you might get cavity wall insulation paid for by GBIS and a first-time central heating system paid for by ECO4 (Ofgem, 2026).
You cannot use both grants for the same measure. You cannot get loft insulation paid for by both GBIS and ECO4. Combining them requires you to meet the eligibility criteria for each grant separately, including income or property type rules (GOV.UK, 2026).
The combined value of these two grants can reach up to £11,500 in 2026 (GBIS maximum £1,500 + ECO4 maximum £10,000).
How to verify an installer and check grant eligibility in 2026
All government energy grant work in England and Wales must be carried out by an installer certified under MCS (for heat pumps) or registered with TrustMark (for insulation and heating controls). In Scotland, check for PAS 2030 certification (GOV.UK, 2026).
You must use the MCS installer database or the TrustMark website to find qualified contractors for combined grant applications (MCS, 2026; TrustMark, 2026). The installer will handle the grant application process, but you must confirm in writing that they can manage multiple grants simultaneously. Ask for a written plan showing which grant covers which measure before work begins.
The featured-snippet answer – can you combine energy grants?
Yes, you can combine the Great British Insulation Scheme (GBIS) with the Energy Company Obligation (ECO4) for different measures in the same home. You cannot combine the Boiler Upgrade Scheme (BUS) with any other grant for the same heating system (GOV.UK, 2026; GOV.UK, 2026).
You must meet the eligibility criteria for each grant individually. The installer must be certified under MCS or TrustMark. The combined value can reach up to £11,500 in 2026 (GBIS maximum £1,500 + ECO4 maximum £10,000) (DESNZ, 2026).
What happens if you apply for two grants for the same measure
Applying for two grants for the same installation, such as a heat pump under both BUS and ECO4, will result in one application being rejected. You may be asked to repay any double payment (GOV.UK, 2026).
Suppliers and scheme administrators cross-check applications through a central database, the ECO Register and BUS portal, to prevent duplication (Ofgem, 2026). Attempting to combine grants incorrectly can delay your project by weeks or lead to the loss of both grants. Always confirm with your installer that each measure is only funded by one grant.
How to apply for multiple energy grants step by step
Follow these four steps to apply for multiple energy grants in 2026.
- Check eligibility for each grant on GOV.UK. The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. Note that income and property type rules differ for each grant.
- Find a single installer certified for both grants. Look for MCS certification for heat pumps and TrustMark registration for insulation. One installer should handle both grants to avoid confusion.
- Ask the installer for a written plan showing which grant covers which measure. This plan must confirm that no measure is funded by two grants.
- Submit separate applications through the installer or supplier. Do not submit duplicate applications for the same measure. Keep copies of all application references and grant approval letters (GOV.UK, 2026; Ofgem, 2026).
