Boiler Upgrade Scheme: What installers need to know
This article is a summary of the key information installers need to know about the Boiler Upgrade Scheme (BUS). This scheme was introduced in 2022 by the Department for Energy Security and Net Zero. The total budget for the 2025/2026 financial year is approximately £295 million, to be allocated as vouchers by Ofgem, the scheme administrator. Installers must apply for BUS scheme vouchers through Ofgem before installing low-carbon heating systems.
Did you know that Intergas offers free installer training courses for all our heating systems? Training includes:
What Is the Boiler Upgrade Scheme?
The Boiler Upgrade Scheme (BUS) is a government financial support scheme to cover part of the costs of low-carbon heating technologies as replacements for fossil fuel heating systems, including gas boilers, oil boilers, LPG and electric central heating. It is available to property owners in England and Wales and is expected to run until early 2028.
Reducing CO2 emissions from home heating is a key part of the government’s plan to meet the UK’s legal obligation to reach net zero by 2050. These made up 14% of the UK’s greenhouse gas (GHG) emissions in 2023, with every gas boiler emitting two tonnes of carbon dioxide every year. The BUS is intended to incentivise homeowners to replace fossil-fuel heating with heat pumps by providing £7,500 towards the cost. This funding is only available when an MCS-registered heat pump installer carries out the installation, so installers apply on the customer’s behalf.
Please note: The BUS is only available for properties in England and Wales. For those in Scotland, the Home Energy Scotland (HES) grant provides up to £15,000 to cover home improvements such as insulation, as well as heat pumps or other clean heating systems. In Northern Ireland, alternative funding may be available through the Northern Ireland Housing Executive.
Hybrid Heating and the Boiler Upgrade Scheme
It is worth noting that hybrid heating, which often combines an air source heat pump with a gas boiler, is also being discussed as a practical way to reduce emissions in homes and help the government meet its net zero commitment. At the time of writing, hybrid heating systems are not eligible for the Boiler Upgrade Scheme, which only supports fully electric heat pumps and biomass installations.
Recent developments, including a policy paper supported by a group of heating industry leaders, suggest hybrid systems could help cut carbon sooner across a wider range of UK homes. Installers should be aware of this ongoing discussion, as government guidance may change or evolve in the coming months and years.
How Does the Boiler Upgrade Scheme Work?
Microgeneration Certification Scheme (MCS) registered installers manage the process on behalf of their customers. Here’s how the BUS works for both installers and homeowners, so you know what to expect.
For Installers
As the installer, you apply to Ofgem and receive the voucher on behalf of the property owner. The customer confirms their consent for the application, and Ofgem issues a voucher. Once installation is complete, you pass the grant on to the property owner as a discount.
- First, create a BUS installer account with Ofgem.
- Advise the property owner on their eligibility.
- Agree on a quote with the property owner and confirm that they want you to use the BUS.
- Apply for the BUS voucher through the Ofgem BUS application page.
- Ofgem then emails the property owner to confirm their consent and eligibility.
- Ofgem emails you, the installer, a voucher for the grant amount. You must complete the installation within 3 months of the voucher issue date (or 6 months for a ground source heat pump). If it expires, you can reapply.
- After installation and testing, generate the MCS installation certificate and redeem your voucher.
- Ofgem conducts final checks and transfers the grant to you.
- Installers then pass on the grant value as a discount by deducting the amount from the customer’s bill.
Because you can only receive the grant after the installation is complete, installers must ensure their cash flow can absorb costs in the interim period.
For Homeowners
To apply for BUS:
- Contact an MCS-certified installer to get a quote for the work.
- Your installer will confirm whether you are eligible for the scheme.
- Agree on a quote and to use the BUS scheme.
- The installer will apply to the scheme, and Ofgem will confirm everything.
- After installation, the value of the grant will be deducted from your invoice.
- MCS might contact you to carry out their own checks.
Note that there is 0% VAT on certain energy-saving materials from April 2022 to 31st March 2027. This means that homeowners looking to install an air source heat pump as part of a wider commitment to renewable energy can potentially save money on other investments, such as solar and battery storage.
What Funding is Available via the Boiler Upgrade Scheme (BUS)?
The Boiler Upgrade Scheme offers one grant per property. The amount available from this scheme depends on the type of heating technology.
- £7,500 for an air source heat pump
- £7,500 for a ground source heat pump or water source heat pump
- £5,000 for a biomass boiler
Ground source heat pumps can be installed for individual properties or as part of a shared ground loop. Any heat pump’s seasonal coefficient of performance (SCOP) must be at least 2.8 to be eligible for the grant scheme.
The eligibility of Biomass boilers is extremely limited. The scheme can only be used for biomass boilers if the property is both in a rural location and has no connection to the gas grid.
Eligibility Criteria for the Boiler Upgrade Scheme
The Installer
Installers must be certified for the relevant technology with the Microgeneration Certification Scheme (MCS).
The Customer
Customers must:
- own the property in question (including businesses, second homes or tenanted properties)
- be replacing fossil fuel heating systems – oil, gas, electric or liquefied petroleum gas (LPG)
- not have already received another grant from public funds towards purchase or installation costs
The Property
The property in question must:
- have a valid Energy Performance Certificate (EPC) (valid for 10 years)
- have an existing fossil-fuel or electric heating system to be replaced by the BUS-funded installation
The property is still eligible if funding has already been used to improve energy efficiency by, for example, adding insulation.
New builds are not eligible unless they are ‘self-builds’, where the building was primarily constructed using either the resources or labour of the owner, and where the date of first occupation is on or after the first commissioning date of the new heat pump. Self-builds are not eligible for biomass boilers.
For a biomass boiler, the property must:
- be in a rural location
- not and never have been connected to the gas grid
- For further advice on property eligibility, check Ofgem’s Installer guidance.
If you’re not sure whether your property is suitable for a low-carbon heating system, such as if your insulation or radiators may need updating to accommodate the system, speak to an MCS-certified installer.
The Technology
The heating system to be installed must:
- replace either a fossil fuel heating system or an electric heating system where no heat pump or biomass boiler is already present
- have a minimum seasonal coefficient of performance (SCOP) of 2.8 (heat pumps only)
- be completely installed within 120 days of the voucher issue date
- meet the full heat and hot water needs of the space
- only provide heating for the property applied for
- have a maximum capacity of 45kWh (if on a shared ground loop, the combined maximum capacity is 300kWh)
- not have been used prior to commissioning
- not be a hybrid system combining heat pumps and fossil fuel heating
Product eligibility is highly situational, so we cannot confirm whether a product is eligible without checking the details of the property in question.
To check product eligibility, Ofgem provides a comprehensive checklist.
What Do Installers Need To Know About the Boiler Upgrade Scheme?
The government scheme relies on installers having a strong understanding of what is eligible and not eligible for the boiler upgrade scheme. The list of criteria for the customer, the property and the technology to be installed is long and complex. Criteria checklists should be consulted carefully before confirming whether a customer is eligible or not.
Mistakes here could lead to denial of your BUS voucher application, or if the ineligibility is discovered after the voucher is granted, higher costs for the customer and a difficult time for your reputation as an installer. Ofgem reserves the right to carry out audits and take action where ineligibility or non-compliance is suspected.
FAQs: Boiler Upgrade Scheme
When does the Boiler Upgrade Scheme end?
The BUS is due to continue until the end of March 2028 at the time of writing. The government have confirmed approximately £295 million in funding for the scheme until that time, so we recommend homeowners take advantage of this opportunity while it is available.
What is the ZEB boiler upgrade scheme?
A ZEB boiler is an electric boiler marketed as a low-carbon heating solution. It heats water with electricity during off-peak hours. It is not currently eligible for the boiler upgrade scheme or any other government grants.
How much is the boiler upgrade scheme?
The boiler upgrade scheme can grant up to £7,500 to cover part of the cost of heat pump installation.
Who is eligible for the boiler upgrade scheme?
Property owners in England and Wales who have a heating system powered directly by fossil fuels are eligible for the scheme in certain circumstances. More detail is available above.
What is excluded from the Boiler Upgrade Scheme?
Installations must fully replace an existing fossil fuel or electric heating system. The BUS does not support replacement gas boilers, oil boilers or electric boilers, and it cannot be used for heating systems in new-build properties, except for eligible self-builds. Systems that combine technologies, such as hybrid heating installations, are also currently excluded, along with properties outside England and Wales.
