ECO4 and the Boiler Upgrade Scheme are two separate schemes with two separate eligibility gates and two separate application processes. The whole thing has a deserved reputation for being confusing. The useful news is that most UK homeowners qualify for at least one of them, and a good chunk qualify for two or three stacked together. That stacking is where the real value lives.
Here's the plain-English version. ECO4 covers insulation and heating for lower-income households. ECO4 LA Flex picks up moderate-income or cold-vulnerable households where the standard means-test doesn't fit. BUS puts £7,500 toward a heat pump for anyone who owns their home. The trick is knowing which combination fits your project.
The three schemes, side by side
| Scheme | What it funds | What you pay | Who qualifies |
|---|---|---|---|
| ECO4 | Insulation, heating, controls, cylinders | £0 typically | Means-tested benefits OR LA Flex (income / health / EPC) |
| ECO4 LA Flex | Same as ECO4 | £0 typically | Income < £31k / cold-vulnerable / EPC E-G |
| BUS | Heat pump only — £7,500 fixed contribution | Net of £7,500 | Valid EPC (no insulation recs open), owner-occupier or private rental |
When ECO4 is the right route
You qualify for ECO4 if any one of these is true: someone in the household gets Universal Credit, Pension Credit, ESA, JSA, Income Support, Working Tax Credit, Child Tax Credit or Housing Benefit; household income is below £31,000 a year; anyone at the address has a cold-sensitive condition (asthma, COPD, heart condition, immunosuppression, child under 5, age 65+ with mobility issues); or your EPC is E, F or G. ECO4 is the highest-value route we have — it routinely covers £4,000–£12,000 of work at £0 to the household.
When ECO4 LA Flex is the right route
ECO4 LA Flex steps in where standard ECO4 doesn't fit. If you don't claim benefits, household income is below £31,000, or anyone at the address has a cold-sensitive condition (asthma, COPD, heart condition) — and your council has a published Statement of Intent — LA Flex unlocks the same ECO4 funding. It can fully fund a loft top-up or cavity wall install, and partially fund a room-in-roof or solid-wall job (typically leaving you £400–£900 to pay on a partial).
When BUS is the right route
BUS is different from the other two. It's not income-gated — anyone who owns their home in England or Wales qualifies, provided the EPC is valid and clean of open insulation recommendations. The £7,500 lands straight on your quote at the design stage; you never pay the full amount and chase a rebate. (Scotland has its own equivalent scheme through Home Energy Scotland.)
A worked stack: 3-bed semi, BUS + ECO4 together
Take a real example from our diary. Family on Universal Credit, EPC D, gas combi at end of life. Project: 9kW ASHP, loft top-up, cavity wall fill and new cylinder. Gross cost: £15,200. BUS covers £7,500 toward the heat pump. ECO4 covers £2,800 toward the insulation and cylinder. What the family actually pays: £4,900 — for a complete heating-plus-insulation upgrade that would cost £15,200 self-funded. That's the stacking effect in plain numbers.
How to find out what applies to your home
A free home survey is the fastest path through. All three eligibility checks happen on the visit. We file the application paperwork on your behalf for whichever scheme (or schemes) fit, and the fixed written quote arrives with the funded portion already stripped out. No fee for the grant admin, no obligation to proceed. Book online, or ring 0800 229 4094. We do all the paperwork.
Want to find out how much you could save?
Book a free 45-minute survey. We’ll check every active grant, measure every wall, and write you a plan. Yours to keep whether you book or not.
The plan is yours to keep. Take it to two other installers if you like.