Boiler Upgrade Scheme (BUS) 2025

Boiler Upgrade Scheme Grant Eligibility: A Complete Guide

The Boiler Upgrade Scheme (BUS) is a government-backed initiative designed to support homeowners in England and Wales in transitioning to low-carbon heating systems. Offering grants of up to £7,500, the scheme provides significant financial assistance towards the installation of air source and ground source heat pumps.

Upgrading an outdated heating system to a more sustainable alternative not only contributes to reducing carbon emissions but also offers long-term savings on energy bills—making this scheme a highly attractive option for eligible households.

Boiler Upgrade Scheme Eligibility

To qualify for the Boiler Upgrade Scheme (BUS), properties must meet specific requirements, which vary depending on whether they are existing buildings or new builds (such as self-builds). Below is a breakdown of the key eligibility criteria for each category:

Existing Homes (Retrofits or Renovations)

Property Ownership: You must own the property (homeowners, landlords, and businesses are eligible). Location: The property must be in England or Wales. Existing Heating System: You must be replacing a fossil fuel system (e.g., gas, oil, electric, or LPG). The scheme does not apply to replacing existing low-carbon systems. Energy Performance Certificate (EPC): Must be issued within the last 10 years. Any recommendations for loft or cavity wall insulation must be implemented before applying (unless exemptions apply). Technology Installed: Air Source Heat Pump: £7,500 grant Ground/Water Source Heat Pump: £7,500 grant Biomass Boiler: £5,000 grant (only for rural, off-gas grid properties)

New Builds (Self-Builds Only)

Eligible New Builds: Only self-build properties are eligible — these are homes built or commissioned by individuals (not developers) for their own use. Evidence of Self-Build: You’ll need to provide proof, such as a completion certificate from Building Control or warranty documentation. Ineligible Builds: Homes built by developers or owned by businesses are not eligible.

Installer Requirements

All installations must be carried out by a certified MCS (Microgeneration Certification Scheme) installer. Installers must apply for the grant on your behalf.

Common Application Issues

From our experience, these are some of the typical issues homeowners face when applying for the Boiler Upgrade Scheme grant:

The 120-Day Deadline

The 120-Day Deadline

As of 8 May 2024, Ofgem has introduced a strict 120-day deadline for grant applications under the Boiler Upgrade Scheme. This means your full application — including any responses to follow-up queries from Ofgem — must be submitted within 120 days of your heat pump’s commissioning date.

Documentation Issues

Getting your paperwork right is essential when applying for the Boiler Upgrade Scheme on a self-build property. Here are two common documentation pitfalls:

Missing or Insufficient Invoices

To prove your property is a self-build, you must provide invoices showing a minimum of £20,000 spent on significant structural work or materials (e.g. foundations, timber frames).

Minor expenses such as kitchen fittings or rewiring are not enough.

Invoices must clearly show the homeowner’s name and the property address.

Missing or incomplete documentation can cause serious delays or even result in your application being rejected.

Invoice Address Errors

Invoices must be addressed to the property owner — not a company — and must match the installation address exactly.

If invoices are in a company name (even if it’s your own), Ofgem may request personal bank statements as proof of payment.

Tip: Double-check all invoices before submitting, and let us help ensure everything meets the criteria from the start.

Documentation Requirements (Retrofits and Renovations)

For retrofits and renovations, the property must have had an existing heating system in place. You’ll need to provide evidence of this — typically through a valid Energy Performance Certificate (EPC). If your EPC already lists a low-carbon system such as an air source or ground source heat pump, you’ll need to supply additional documentation confirming the previous fossil fuel heating system. If the property has a secondary heating system, like a wood burner, Ofgem may request clarification about how it’s used. Good news: Your EPC rating does not affect your eligibility. You don’t need to renew your EPC to apply for the Boiler Upgrade Scheme — even if you’re renovating the property.

Planning Permission Requirements

For new builds, planning permission must be obtained by the homeowner as an individual — not through a developer or company. Applications tied to planning permission secured by a company are typically rejected.

Complex Ownership Scenarios (e.g., Gifting or Inheritance)

If the property involves gifting, inheritance, or has separate funders, you’ll need to provide extra documentation. This could include a solicitor’s letter or a copy of the build contract. These cases can be more complex and often benefit from tailored advice to ensure the application is successful.

Do Not Operate the Heat Pump Before Commissioning

It’s essential not to use the heat pump before its official commissioning date. Premature operation may risk your eligibility for the BUS Grant, as the scheme requires the system to be used only after formal commissioning and as part of the approved installation process.

Boiler upgrade scheme Grant Application Timeline

Understanding the timeline of a Boiler Upgrade Scheme grant application is crucial for ensuring everything runs smoothly. Here’s an outline of the process, from the moment we request information to when you receive your grant funds.

Step 1: Requesting Information (Pre-Commissioning)

Once the Technical Sign Off (TSO) is completed, we begin requesting all the necessary information and documents from you. We aim to gather everything before the heat pump commissioning takes place. This gives us time to carefully review and ensure that all documents are correct and compliant with the Boiler Upgrade Scheme requirements.
Step 2: Commissioning and Application Submission

After the heat pump is commissioned, we have a 120 day window to complete all necessary paperwork and issue the MCS Certificate for your installation, which is required to redeem the grant from the government. We aim to submit the application immediately after the commissioning to ensure we stay within the 120-day deadline.
Step 3: Awaiting Ofgem Approval

Once the application is submitted, Ofgem will review the information and documentation. In some cases, they may request further information or clarification. If additional information is required, we’ll promptly address it to keep the process moving forward.
Step 4: Redemption Process

After receiving approval from Ofgem, we will proceed with the voucher redemption. Our accounting department will submit the necessary paperwork to redeem the grant from Ofgem. This process typically takes 2-3 weeks from the time the voucher is approved.
Step 5: Snags and Final Works

If there are any minor works or snags to complete after commissioning (e.g., awaiting confirmation that further works have been finished or receiving the EIC for the property), we must ensure all snags are completed before we can proceed with the funds transfer. This ensures that everything is fully compliant and meets the necessary standards for the grant.