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Not all boilers qualify. Not all homeowners get a grant. And most people applying don’t know the difference until it’s too late. The Boiler Upgrade Scheme (BUS) offers up to £7,500 – but it targets a very specific type of home, a very specific type of system, and it will not bend for anyone who hasn’t done their homework. Let’s fix that right now.
What the Boiler Upgrade Scheme Actually Does
BUS is a government grant that pays you to ditch fossil fuels. It’s not a repair fund. It’s not a “make my old boiler work better” scheme. It’s a full replacement programme designed to shift UK homes off gas and oil and onto low-carbon heating – for good.
Administered through MCS-certified installers, the grant is applied directly against your installation cost. You don’t claim anything. You don’t wait for a cheque. Your installer deducts it upfront, and the government reimburses them. Simple.
Here’s what most people get wrong: BUS does not fund a new gas boiler. Not a condensing one. Not an A-rated one. Not even the most efficient model on the market. If that’s your goal, ECO4 is your scheme – not this one. BUS is for homeowners ready to go low-carbon, and it rewards them well for doing so.
What Does BUS Fund?
Three replacement systems qualify under BUS. That’s it. Three.
| Replacement System | Grant Available |
|---|---|
| Air Source Heat Pump | £7,500 |
| Ground Source Heat Pump | £7,500 |
| Biomass Boiler | £5,000 |
Biomass is the outlier here – it only makes sense in rural properties where a heat pump isn’t viable. For most homes, the conversation starts and ends with heat pumps.
Which Existing Boilers Qualify for Replacement?
Here’s the detail that matters. BUS doesn’t care how old your boiler is. It doesn’t care if it breaks down every winter. The only question BUS asks is: what fuel does your current system burn?
If the answer is a fossil fuel, you’re eligible to replace it. If your home already has a heat pump or another low-carbon system, BUS has nothing to offer you.
The Fossil Fuel Systems That Open the Door
Any gas boiler qualifies as a starting point – combi, system, or conventional. So does oil, LPG, or direct electric heating. Even old back boilers hiding behind fireplaces qualify. The table below makes it clear:
| Existing Heating System | Qualifies Under BUS? |
|---|---|
| Gas combi boiler | Yes |
| Gas system boiler | Yes |
| Oil boiler | Yes |
| LPG boiler | Yes |
| Back boiler (gas or oil) | Yes |
| Electric storage heaters | Yes |
| Existing heat pump | No |
| Biomass replacing biomass | Usually No |
A five-year-old gas combi qualifies exactly the same as a twenty-year-old back boiler. Age is irrelevant. Fuel type is everything.
Do You Need Insulation First?
You used to. Before the 2026 rule updates, BUS required loft and cavity wall insulation before a heat pump could be approved. That mandatory condition has been removed. You no longer need to pass an insulation check to access the grant.
That said, any competent MCS-certified installer will still assess your home’s heat loss before sizing a system. Why? Because an undersized heat pump in a draughty home won’t perform, and a failing installation damages their certification. Good installers self-police this.
Check Eligibilty For ECO4 Scheme
Get Free Heating System Installed Today at your Property Under ECO4!
The Property Rules That Catch People Off Guard
Qualifying with the right boiler type is only half the equation. BUS has property-level conditions too – and they eliminate a lot of applicants who thought they were in.
The scheme has three hard rules: you must own the property, the property must be in England or Wales, and the replacement system must be under 45kW output capacity. There is no flexibility on any of these.
Tenants cannot apply directly, even with a failing, inefficient gas boiler driving up their bills. The landlord must apply, and landlords have separate incentive structures to navigate.
Scotland uses the Home Energy Scotland Grant and Loan. Northern Ireland has devolved funding. The bus stops at the border.
BUS vs ECO4 - Stop Confusing Them
These two schemes get conflated constantly, and it costs people time. They serve different households, fund different technologies, and have completely different eligibility logic.
| Feature | Boiler Upgrade Scheme | ECO4 |
|---|---|---|
| What it funds | Heat pump or biomass | Efficient gas boiler |
| Income test | None | Yes – benefits or under £31k |
| EPC requirement | None | EPC E–G |
| Who can apply | Homeowners only | Homeowners and tenants |
| Location | England and Wales | GB-wide |
| Fossil fuel replaced | Must be | Must be inefficient |
| Grant value | Up to £7,500 | Fully funded if eligible |
The decision tree is straightforward. On Universal Credit with an ancient gas boiler? ECO4. Homeowner who earns above the ECO4 threshold and wants to cut carbon? BUS. Stop trying to make one scheme do the job of the other.
The Bottom Line
You don’t apply to the Boiler Upgrade Scheme directly – and that’s a deliberate design choice. The government routes everything through MCS-certified installers to ensure only compliant systems get funded.
Here’s how the process runs:
- Find an MCS-certified installer. They confirm eligibility, assess your property, and size the system correctly.
- Receive a quote with the grant deducted. The £7,500 comes off the total – you pay the remainder.
- The installer applies on your behalf. They claim the grant from Ofgem post-installation.
- Retain all documentation. That means your MCS certificate, building regulations sign-off, and product warranties.
One critical detail: BUS cannot be combined with the Warm Home Discount or used simultaneously with ECO4 measures on the same property. Pick your route and commit to it.
FAQs
No. BUS doesn’t care about boiler condition – only fuel type. A perfectly working gas boiler qualifies for replacement under BUS.
No. BUS funds heat pumps and biomass only. No gas boiler – however efficient – qualifies as a BUS replacement.
No income test applies. BUS is open to any eligible homeowner in England or Wales, regardless of earnings.
No longer. The mandatory insulation requirement was removed in the 2024 updates. However, poor insulation will affect heat pump performance, so expect your installer to raise it.
