Replacing an old heating system with a heat pump can involve a substantial upfront cost, which is where the Boiler Upgrade Scheme becomes relevant.
The scheme provides a grant towards eligible low-carbon heating systems in England and Wales. The application is handled by the installer rather than requiring the homeowner to claim the money independently after the work is complete.
The amount available is not identical for every property. The heating technology, existing heating system, and whether the property is connected to the mains gas network can affect the grant category.
The rules were updated in July 2026, so older articles can now give homeowners an incomplete picture of the current support.
How Much Can The Boiler Upgrade Scheme Contribute?
The boiler upgrade scheme currently provides £7,500 towards an eligible air-to-water heat pump and £7,500 towards a ground-source heat pump.
The other grant categories are £2,500 for an eligible air-to-air heat pump and £5,000 for a qualifying biomass boiler. A property can receive one grant under the scheme.
There is a higher grant for certain off-gas-grid properties.
From 21 July 2026, qualifying off-gas-grid properties replacing oil or LPG heating can receive £9,000 towards an eligible air-to-water or ground-source heat pump. The £9,000 category also covers certain other specified existing heating systems in off-gas-grid properties.
This distinction is important because “off-gas-grid” by itself does not guarantee the higher payment. The existing heating source and proposed technology still have to fit an approved category.
Why The Existing Heating System Needs To Be Checked
A homeowner cannot work out the grant solely from the heat pump they intend to buy.
The existing heating system matters.
For example, an eligible property connected to the gas network may receive the standard £7,500 grant for an air-to-water heat pump. An eligible off-gas-grid property replacing oil or LPG can fall into the £9,000 category under the current rules.
The government has also defined different grant categories for other heating sources, including coal, certain fossil-fuel hybrid systems and electric heating that is not itself a heat pump.
This is why the installer should establish what currently heats the property before the homeowner calculates the expected contribution.
A homeowner replacing an old oil boiler should not automatically assume that every quotation will show the same grant amount as a gas-heated property.
What Properties Are Covered?
The scheme is available for properties in England and Wales, including residential and certain non-residential properties.
Property ownership is relevant because the scheme is intended for property owners. The rules also contain specific provisions for self-build properties.
New-build properties are generally excluded, although qualifying self-build properties can be eligible. Social housing is excluded, as are properties that have already received government funding for the purchase or installation of the heat pump or biomass boiler being proposed.
The existing heating system also needs to be eligible for replacement.
A BUS grant cannot normally be used to replace an existing low-carbon heating system with another low-carbon system.
Which Heating Technologies Qualify?
The scheme does not cover every type of heating technology described as renewable or low carbon.
Eligible categories include air-to-water heat pumps, air-to-air heat pumps, ground-source heat pumps and biomass boilers. Ground-source support also covers certain water-source systems and shared ground loops.
There are technical conditions attached to the equipment.
For heat pumps, the system needs to be capable of meeting the property’s full space-heating requirements and must satisfy the relevant efficiency standards.
A hybrid arrangement consisting of a fossil-fuel boiler and an air-source heat pump is not eligible for a BUS grant.
This makes the system specification important. The grant is tied to an approved installation, not simply to the presence of a heat pump.
What Happens Before The Grant Application?
The process starts with quotations.
The homeowner contacts suitable MCS-certified installers and discusses the property, existing heating system and proposed replacement. Once eligibility and the installation details have been established, the homeowner agrees a quotation.
The installer then applies for the BUS grant on the homeowner’s behalf. GOV.UK states that the grant value is deducted from the amount the homeowner pays, and the reduction should appear on the quotation and invoice.
This means the homeowner should be able to see three separate figures:
- The cost of the installation
- The grant contribution
- The remaining amount to pay
Keeping those figures separate makes quotations much easier to compare.
What If You Are Searching For A Local Installer?
Someone searching for a boiler upgrade or another local service should look beyond location when comparing installers.
BUS installations need to be carried out and commissioned by an MCS-certified installer. Ofgem also advises property owners to obtain quotations from multiple installers.
Once certification has been checked, the technical proposal deserves close attention.
Ask how the heat pump has been sized. A heat pump should be selected according to the property’s heat demand rather than simply matching the output rating of the existing boiler.
Ask whether a heat-loss assessment has been carried out and whether the existing radiators are suitable for the proposed system.
The same applies to hot-water storage, controls and pipework. If modifications are needed, they should appear in the quotation rather than being treated as an unexpected addition halfway through the project.
Why Heat-Loss Calculations Matter
A boiler and a heat pump do not necessarily operate in the same way.
An installer needs to understand how much heat each part of the property requires, particularly during colder conditions. This helps determine the heat pump’s required capacity.
The assessment can also identify rooms where existing radiators may not provide enough heat at the operating temperatures planned for the new system.
That does not mean every radiator automatically needs replacing.
The requirement depends on the building, heat loss, radiator output and proposed system design. A proper assessment can show where changes are actually needed rather than replacing components unnecessarily.
This is one of the areas where a detailed quotation can tell you much more than the grant figure.
Does The Grant Cover The Whole Installation?
The grant is a contribution, not a promise that the entire installation will be free.
The remaining cost depends on the installation price and any additional work required at the property.
A straightforward air-to-water heat pump installation may have a different final price from one requiring extensive radiator changes, new hot-water storage, pipework alterations or electrical work.
This is why comparing the grant amount alone can be misleading.
If two installers both show a £7,500 grant but one quotation is £15,000 and the other is £19,000, the homeowner still needs to understand why the overall project prices differ.
The specification and scope of work provide the explanation.
What Happens After The Installer Applies?
Once the application is made, Ofgem contacts the homeowner to confirm that the installer is acting on their behalf. Ofgem or MCS can also carry out checks relating to the installation.
The installer then completes the work and submits the required information to claim the grant.
There are time limits for completing the project. Ofgem currently states that the installer has three months after application approval to complete a standard installation, with six months allowed for ground-source heat pumps. If the installer misses the applicable deadline, a new application may be required.
That makes the installation schedule worth discussing before the application is submitted.
What Should Be Included In The Quotation?
A useful BUS quotation should explain the whole heating project, not just display the grant amount.
Look for the heat pump make and model, proposed capacity, controls, hot-water arrangements and any changes to radiators or pipework.
Check whether electrical work, commissioning and system controls are included.
The quotation should also show the grant deduction separately from the gross installation price.
If the installer expects preparatory work to be necessary, ask whether that work is included and whether it is eligible for the grant. This prevents confusion over what the government contribution actually covers.
It is also sensible to ask what documentation will be provided after commissioning.
Can The Scheme Be Used For A Hybrid Heat Pump?
Not every heat pump arrangement qualifies.
A system that combines a fossil-fuel boiler with an air-source heat pump is specifically excluded from BUS funding under the current rules.
This matters because homeowners may encounter different types of hybrid heating systems when researching replacements.
If a quotation describes itself as a hybrid system, ask the installer to confirm its BUS eligibility before assuming that the grant will be available.
The proposed equipment should be checked against the current scheme requirements rather than relying on the general description used in advertising.
What Should You Check Before Applying?
Start with the property rather than the grant.
Confirm that the property is eligible, identify the existing heating system and establish whether it is connected to the mains gas network.
Then ask installers to explain which grant category applies and why.
Compare the complete heating designs, including heat-loss calculations, heat pump capacity, radiator requirements, hot-water arrangements and controls. Check the gross installation price before considering the grant deduction.
Finally, confirm who is responsible for the BUS application and what happens if the installation schedule changes.
The grant can reduce the initial cost of moving to low-carbon heating, but the quality of the project depends on more than the amount deducted from the invoice. The proposed system needs to be suitable for the building, correctly sized and installed in accordance with the scheme requirements.
