ECO4 vs Boiler Upgrade Scheme — What's the Difference?
Two different government schemes, two very different purposes. Here's everything you need to know.
| Feature | ECO4 Scheme | Boiler Upgrade Scheme (BUS) |
|---|---|---|
| Purpose | Free gas boiler replacements for low-income households | Grants for heat pumps for any homeowner |
| Who Qualifies | Low-income households on qualifying benefits or LA Flex | Any homeowner in England or Wales (no means test) |
| Grant Value | Up to £15,000 (full cost covered) | £7,500 for air/ground source heat pumps |
| Covers Gas Boilers? | Yes — free gas combi boiler replacement | No — gas boilers are not eligible |
| Covers Heat Pumps? | In some cases, where appropriate | Yes — this is the primary purpose |
| Cost to Applicant | £0 — completely free | Partial — you pay the remainder above the grant |
| Funded by | Energy suppliers (legal obligation) | UK Government (DESNZ) |
| Ends | 31 December 2026 | 31 March 2028 |
What is the ECO4 Scheme?
The ECO4 scheme (Energy Company Obligation 4) is a means-tested government programme that provides completely free energy efficiency improvements — including free gas boiler replacements — to eligible low-income and vulnerable households. To qualify, you need to receive a qualifying benefit (such as Universal Credit or Pension Credit) and live in a property with an EPC rating of D, E, F, or G. The entire cost is covered — you pay nothing.
What is the Boiler Upgrade Scheme (BUS)?
The Boiler Upgrade Scheme (BUS) is a government grant scheme that provides a £7,500 grant towards the cost of installing an air source or ground source heat pump, or a £5,000 grant towards a biomass boiler. It is available to any homeowner in England or Wales — there is no means test and no benefit requirement. However, it does NOT cover gas boiler replacements, and you will still need to pay the difference between the grant and the total installation cost (heat pumps typically cost £10,000–£20,000 in total).
Which Scheme Should I Apply For?
If you receive qualifying benefits and have a poor EPC rating, ECO4 is almost certainly the right choice — it provides a completely free gas boiler replacement with no cost to you whatsoever. The Boiler Upgrade Scheme is better suited to homeowners who do not qualify for ECO4 but want to transition to low-carbon heating and can afford to contribute to the cost of a heat pump installation.