Boiler Upgrade Scheme (BUS)

Scheme eligibility

This page summarises key information about the Boiler Upgrade Scheme (BUS) for installers.

For full scheme details, we encourage you to read the BUS guidance for installers.

Some of the key eligibility criteria for the scheme are set out below. For a full explanation of all eligibility criteria, see chapter 3 of the BUS guidance for installers.

Installer eligibility

To apply for a grant on behalf of a property owner, your business must be certified to install the relevant technology with the Microgeneration Certification Scheme (MCS), or equivalent scheme should one become available.

Property eligibility

In order to be eligible for a BUS-funded installation, a property must:

  • be in England and Wales
  • have a valid EPC issued within the last 10 years
  • (retrofits only) have an existing fossil-fuel or electric heating system that’s being replaced by the BUS-funded installation

Properties cannot be:

  • social housing
  • new builds (except where they are ‘eligible self-builds’ that have been built mainly using the labour or resources of the first owner, have never been owned by a business or organisation and are not part of an excluded property development)

Eligible technologies

The following technologies are eligible for the BUS:

  • air source heat pumps (not including air-to-air heat pumps)
  • ground source heat pumps
  • ground source heat pumps as part of a shared ground loop
  • biomass boilers

Other eligibility criteria

Installers must ensure that the new heat pump or biomass boiler complies with requirements of the BUS regulations. These include that:

  • the new heat pump or biomass boiler will be commissioned no more than 120 days prior to the voucher application being properly made
  • the new heat pump or biomass boiler meets the standards approved and published by the Secretary of State (to help you check, you can use the Boiler Upgrade Scheme product eligibility list, which is a subset of the MCS product eligibility list)
  • the new heat pump or biomass boiler will provide heating for the purpose of space heating and hot water heating
  • the new heating system will be capable of meeting the full space and water heating needs of the property, and it is designed to do so
  • the new heating system will only provide heating to the property being applied for (and any ‘related properties’ that are not included on the EPC)
  • the new heat pump or biomass boiler will distribute heat using a liquid, for example through radiators or underfloor heating
  • the new heating system will have a maximum capacity of 45kWth (for shared ground loops, the combined capacity of all heat pumps on the shared loop cannot exceed 300kWth)
  • the new heat pump or biomass boiler will not have been used prior to commissioning, except in limited circumstances, eg to dry out plasterwork during construction or renovation (for shared ground loops, a new heat pump can connect to an existing shared loop)
  • the new heating system will not be a hybrid system that combines a heat pump with fossil fuel heating
  • all heat-generating components of the original heating system will be replaced (where applicable, you may retain circulation pumps, solar thermal collectors, wood-burning stoves, and supplementary electric heaters, including immersion heaters)
  • the new heating system will replace either a fossil fuel heating system or an electric heating system
  • the new heating system will not replace a system that already contains a heat pump or biomass boiler
  • the property owner has not received another grant from public funds to cover any of the purchase or installation costs
  • the new heating system has not have been funded by the Energy Company Obligation (ECO)
  • the property owner at the installation address will own the new heating system after it is installed

An additional requirement for heat pumps only is that they: 

  • have a minimum seasonal coefficient of performance (SCOP) rating of 2.8

In addition, biomass boilers:

  • can only be installed in rural properties 
  • can only be installed in properties that are not, and have never been, connected to the gas grid
  • cannot be installed in self-builds
  • must have an emissions certificate to show they meet certain emissions standards for the scheme

How the scheme works


1. You must create a BUS installer account before you can submit BUS applications. Find out how to do this on the 'Sign up and apply' page.


2. You advise the property owner on whether a proposed installation is eligible for a grant.

3. Together, you agree a quote for the project.

4. You also both agree that you can submit a BUS voucher application on the property owner’s behalf.

Application and property owner consent

5. You apply for the BUS voucher on behalf of the property owner. Find out how to do this on the 'Sign up and apply' page.

6. Ofgem emails the property owner and asks them to confirm that they consent to you making an application on their behalf. Property owners will also need to confirm some details about their eligibility for the scheme.

7. After conducting eligibility checks, Ofgem emails you a voucher for the grant amount.

Installation and commissioning

8. From the date the voucher is issued, you have 3 months to complete the installation (6 months for a ground source heat pump). If the voucher expires before you have commissioned the installation, you can re-apply for another BUS voucher - go back to Step 5.

Voucher redemption and payment

9. After you've commissioned the new system and generated the MCS installation certificate, you can apply to Ofgem to redeem your voucher.

10. Ofgem conducts final eligibility checks, which include reviewing the details on the MCS installation certificate.

11. Once a redemption application has been approved, it will be processed for payment, along with all other redeemed vouchers, on the next scheduled payment day. Scheduled payment days will occur on a weekly basis.

Audit and compliance

To ensure installers and installations comply with scheme regulations, Ofgem has the power to conduct audits and take action where ineligibility or non-compliance is suspected or discovered.

These can be either site or desk audits and can occur at any point after you've made a BUS application, including after you’ve been paid the grant.

For full details of our audit and compliance powers and activities and how they affect you, see chapter 9 of the BUS guidance for installers.

Sign up and apply

Installers - sign up and apply for the BUS