The Boiler Upgrade Scheme (BUS) is a capital grant for England and Wales, administered by Ofgem, that pays a contribution toward the cost of installing a heat pump or biomass boiler in place of a fossil fuel heating system. The payment goes to the MCS (Microgeneration Certification Scheme)-certified installer as a deduction off the quoted price, and it applies to replacing an existing oil, LPG or coal system.

The condition that separates biomass from a heat pump

Heat pumps are open to most properties that meet the standard scheme requirements, but biomass boilers are treated more narrowly. Eligibility for a biomass grant under BUS generally depends on the property being off the mains gas grid and falling within a rural area classification the scheme uses. That single condition, rural classification plus no gas connection, decides whether a biomass boiler is fundable before any other factor, such as house size or fuel storage, comes into it. A property that sits on the gas grid, or is off-grid but outside the rural classification, is unlikely to qualify for biomass funding through BUS, and that needs checking against the scheme's own criteria.

What the scheme expects of the property

• A valid Energy Performance Certificate (EPC) with no outstanding recommendation for loft or cavity wall insulation, unless installing that insulation isn't practical for the building.
• An existing fossil fuel heating system being replaced.
• A domestic property in England or Wales; Scotland and Northern Ireland run their own separate arrangements.

What is funded, and what sits outside it

The grant contributes toward the boiler and its installation. It does not extend to building a pellet store, to flue or chimney work beyond what the installation itself needs, or to ongoing running costs once the system is in. The installing company has to be MCS-certified for the work to count toward the scheme at all, and the boiler generally needs to meet MCS product standards, so a quote from an uncertified installer, however competitive, will not bring the grant with it.

Because rural classification, EPC status and the gas-grid position vary by address, none of this can be confirmed from a general description of a house. See Biomass Against a Heat Pump: An Honest Comparison for how the two options compare where a property could go either way, and Is Biomass Heating Right for Your House? for the wider set of conditions, storage space, flue routing, heat demand, that determine whether biomass suits the building regardless of grant funding.

The Boiler Upgrade Scheme (BUS) is run by Ofgem, and its official page is the only place to confirm current eligibility rules, application steps and grant amounts. This site cannot confirm whether a given property or appliance qualifies today, because the scheme's terms have changed before and can change again. Check the Ofgem BUS page directly before you plan around any figure you have seen quoted elsewhere.

What to have ready before you check

Ofgem's eligibility check asks for specifics about the property and the proposed system. Having these to hand before you start makes the check faster and less likely to stall halfway through.

• Property address and confirmation of whether it is off the gas grid, since this affects which heating systems qualify
• Details of the existing heating system being replaced
• Confirmation that the installer carrying out the work is MCS-certified (the Microgeneration Certification Scheme, which certifies installers of low-carbon heating systems), since BUS grants are generally paid through the installer
• The proposed biomass boiler's specification, since not every biomass appliance or configuration is treated the same way under the scheme

None of this replaces reading the current Ofgem guidance in full. It simply means the check does not have to be interrupted while you go and find a boiler serial number or an installer's certification number.

Why an installer's word is not the scheme's word

An installer can tell you what they believe qualifies, and most are giving that answer in good faith. But eligibility is decided by Ofgem against the scheme's published rules.

An installer has a commercial interest in the sale going ahead, which is a different thing from having the final say on a grant. Where an installer's claim and the Ofgem page disagree, or where the installer cannot point you to the specific rule they are relying on, treat the Ofgem page as the answer. Verify the installer's own certification separately on the MCS register, since BUS funding depends on the work being carried out by an MCS-certified installer.

Where to go next

Check the current rules on the official Ofgem Boiler Upgrade Scheme page before assuming anything about a specific property qualifies. If you are still weighing biomass against other options for an off-grid property, the comparison of biomass against a heat pump covers the conditions under which each tends to make more sense, and the wider grants and schemes guide sets BUS alongside the other funding routes available for biomass heating.