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Despite having the word 'boiler' in the title, the Boiler Upgrade Scheme, or BUS for short, is an upfront government grant of £7.5k for fitting an air source heat pump (ASHP) or a ground source heat pump (GSHP). The scheme replaced the outgoing Renewable Heat Incentive (RHI) with a voucher-based system, although the criteria is largely the same. 


The BUS will run from 1st April 2022 to 31 March 2028 and a £7.5k grant is available from 23 Oct 2023.


1) Introduction

The new BUS scheme is designed to encourage households in England and Wales to switch to an ASHP, GSHP or biomass boiler via upfront grants. A total of £450 million has been allocated, with a cap of £150 million per year. The scheme will part fund the installation of up to 60,000 renewable heat sources over the next six years.


2) Eligibility criteria by property

Eligibility varies according to technology, as set out below. For the purposes of clarity, households do not need to have a whole-house retrofit assessment. As per the current RHI scheme, households must have an EPC (that is less than 10 years old) with no outstanding recommendations for loft or cavity wall insulation.

NB not having loft or cavity wall insulation does not prevent you from applying for the voucher, but they must fitted during the voucher period before the installation.


  • Must be replacing a fossil fuel boiler of any kind or direct electric heating system (such as storage heaters, electric panel radiators or an electric boiler).

  • Custom new builds are eligible and do not require an EPC.

  • If you are in a listed property or conservation area the same exemptions apply as they did for the RHI.

3) Eligible technologies

  • MCS accredited ASHPs, GSHPs and biomass boilers are eligible.

  • ASHPs and GSHPs must have a minimum efficiency in the home of 2.8 SCOP


4) Exclusions

  • Hybrid systems comprising gas/oil boiler and heat pump - are not eligible.

  • ‘Heat-only’ systems where the heat pump or biomass boiler only provides space heating and hot water is supplied by a fossil fuel boiler. Immersions for topping up the hot water and for anti-legionella protection are permitted. Solar thermal is also permitted as long as the heat pump or biomass boiler is set up to meet the full space and water heating demand. 


5) How the voucher scheme works

The voucher scheme is in two stages and is fully ‘installer-led’, which means the installer will apply for the voucher on your behalf and claim the voucher rebate at the end of the works:

  • Stage 1: voucher application

You must go to an MCS registered installer who will provide you with a quote and make the application for the voucher. The quote is required to give you an idea of price before proceeding further. A single installer will lead the voucher application process, however you are encouraged to seek other quotes. The value of the voucher will be deducted from the installation cost, i.e. you will pay the lower price and the installer will claim the voucher directly.

  • Stage 2: voucher redemption

On completion, the MCS installer will submit evidence including proof of installation and technical evidence relating to the installation, commissioning and building eligibility. The grant will be paid directly to the installer.


6) Time limits

ASHP and biomass vouchers have a 3-month time limit, i.e. the works must be completed and the voucher claimed in that period or the voucher will be recycled back into the funding pot. GSHP vouchers have a 6-month time limit.

If it looks at though the £150m funding will run out before the end of the financial year, a quarterly cap will be introduced to limit vouchers and widely publicised. If the cap is in place, vouchers may run out before the end quarter and you will have to wait until the next quarter to apply. 


7) Post installation requirements

In short, there are none. Households are not required to report on the performance of the system after installation and smart metering/monitoring (currently funded) is only encouraged and there is no funding.


8) Consumer protection

Consumers are well protected if certified companies are used. 

The voucher scheme has been designed to focus on pre-installation audit and compliance checks to ensure eligibility. Some changes have taken place to the MCS certification practices, whereby the design and installation of systems can be carried out by different parties.


To ensure you are fully protected, and to avoid bad installations, click on this link to The Heating Hub website:

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