grants

How to Apply for the Boiler Upgrade Scheme: Step-by-Step Guide (2026)

James Mitchell |
boiler upgrade scheme BUS grant heat pump grant government funding how to apply

Introduction

The Boiler Upgrade Scheme (BUS) is the UK government's flagship grant programme for homeowners switching from fossil fuel heating to a heat pump. It currently offers 7,500 pounds towards the cost of an air source or ground source heat pump, making the transition significantly more affordable. The scheme has been extended to run until April 2028, giving you plenty of time to plan your installation properly.

Despite the generous funding, the application process can feel confusing if you have never navigated a government grant before. This guide walks you through every step, from checking your eligibility to receiving your voucher, so you know exactly what to expect and how to avoid the pitfalls that delay or derail applications.

For an overview of all available heat pump funding options, see our dedicated heat pump grant guide.

Eligibility Checklist

Before you contact an installer, confirm that you meet all the eligibility criteria. Getting this wrong is the single most common reason applications fail.

Your Property Must:

  • Be in England or Wales. Scotland has its own funding scheme (Home Energy Scotland). Northern Ireland has separate arrangements.
  • Have a valid Energy Performance Certificate (EPC). Your property must have an EPC with no outstanding recommendations for loft or cavity wall insulation. If your EPC is older than ten years, you will likely need a new one.
  • Replace a fossil fuel heating system. The scheme covers replacement of gas boilers, oil boilers, LPG systems, electric storage heaters or direct electric heating. It does not cover replacing an existing heat pump with a new one.
  • Not be a new build. Properties that have not previously been occupied are excluded. Self-build projects may qualify if the property has been occupied and had a fossil fuel system installed.

You Must:

  • Own the property (or be a landlord replacing the system in a rental property you own).
  • Not have already received a BUS voucher for the same property.
  • Use an MCS-certified installer. This is non-negotiable. Only installations carried out by an MCS-certified company qualify for the grant.

The Heat Pump Must:

  • Be MCS-certified equipment. Your installer will ensure this, but it is worth confirming.
  • Be appropriately sized for your property's heat demand, as determined by a proper heat loss calculation (not a rough estimate).
  • Meet the MCS 020 Planning Standard for noise, if it is an air source system.

The Four Steps to Getting Your Grant

Step 1: Get an EPC (If You Do Not Have One)

Check whether your property has a valid EPC by searching on the GOV.UK EPC register. If your certificate has expired, has loft or cavity wall insulation recommendations that have not been addressed, or does not exist at all, you will need to arrange a new assessment.

An EPC assessment costs between 60 and 120 pounds and is carried out by a qualified domestic energy assessor. The process takes about an hour. Once issued, the certificate is valid for ten years.

Important: If your EPC recommends loft insulation or cavity wall insulation, you must either install these measures before applying for the BUS, or demonstrate that the recommendation is not applicable (for example, if your home has solid walls rather than cavity walls). Your installer can advise on this.

You can use our suitability checker to get an initial assessment of whether your home is ready for a heat pump.

Step 2: Find an MCS-Certified Installer

This is the most important step in the entire process, because your installer handles the grant application on your behalf. You do not apply directly to Ofgem yourself.

When choosing an installer:

  • Verify MCS certification. Check the MCS Certified installer database to confirm the company is currently registered.
  • Get at least three quotes. Prices vary significantly between installers, and the cheapest quote is not always the best value.
  • Ask about their BUS experience. An installer who has processed dozens of BUS applications will navigate the paperwork faster and with fewer errors.
  • Confirm what the quote includes. The quote should cover the heat pump unit, installation, hot water cylinder (if needed), any radiator upgrades, commissioning and the BUS application.

Our installer finder helps you connect with vetted, MCS-certified professionals in your area.

Step 3: Your Installer Applies for the Voucher

Once you have accepted a quote, your installer submits the BUS application to Ofgem on your behalf. This is done through the Ofgem BUS portal. The application includes:

  • Your property details and EPC reference number
  • The proposed heat pump make and model
  • The total quoted installation cost
  • Evidence that the system has been designed according to MCS standards (including heat loss calculations)
  • Your consent as the property owner

What happens next:

  • Ofgem reviews the application and, if everything is in order, issues a voucher within approximately four weeks.
  • The voucher is valid for three months from the date of issue. The installation must be completed and the voucher redeemed within this window.
  • If the voucher expires, a new application must be submitted.

Step 4: Installation and Voucher Redemption

With the voucher issued, your installer schedules the installation. For a typical air source heat pump, expect the work to take two to three days. Ground source systems take longer, particularly if boreholes or trench work are required.

After installation, your installer:

  1. Commissions the system and verifies it is operating correctly.
  2. Registers the installation with MCS.
  3. Submits a redemption request to Ofgem with evidence of completed work.
  4. Ofgem pays the 7,500 pounds grant directly to the installer.

The grant is deducted from your total bill. You pay the remaining balance to your installer. For example, if your total installation cost is 11,000 pounds, you pay 3,500 pounds after the 7,500 pound BUS grant is applied.

Timeline: How Long Does It All Take?

StageTypical duration
Getting an EPC (if needed)1 to 2 weeks
Getting quotes from installers2 to 4 weeks
BUS application and voucher issue3 to 4 weeks
Installation scheduling2 to 8 weeks (depends on installer availability)
Installation itself2 to 5 days
Voucher redemption2 to 4 weeks after installation

Total from first enquiry to operational heat pump: typically 10 to 18 weeks.

Planning ahead is important. Installer availability tends to be tightest in autumn and early winter, when demand spikes. Starting the process in spring or summer gives you the best chance of having your system running before the cold weather arrives.

What Does the Grant Cover (and What Does It Not)?

Covered:

  • Air source heat pumps (including air-to-water systems)
  • Ground source heat pumps (including shared ground loop systems)
  • The 7,500 pound grant applies to both ASHP and GSHP

Not Covered:

  • Air-to-air heat pumps (these are classed as air conditioning, not central heating)
  • Hybrid heat pump systems (heat pump plus gas boiler combinations)
  • Biomass boilers (these were removed from the scheme in 2024)
  • Any work that is not directly part of the heat pump installation (such as full rewiring or structural alterations)

For a comparison of the different heat pump types and their costs, see our guides on air source heat pump costs and ground source heat pump costs.

Common Mistakes to Avoid

1. Applying Without a Valid EPC

This is the most frequent cause of rejected applications. Always check your EPC status before your installer submits the BUS application.

2. Choosing a Non-MCS Installer

Only MCS-certified installers can apply for the BUS. If you hire an uncertified installer, no matter how competent they may be, you will not receive the grant.

3. Underestimating Insulation Requirements

If your EPC flags loft or cavity wall insulation as a recommendation, this must be resolved before the BUS application can proceed. Budget for these improvements early in your planning.

4. Leaving the Voucher to Expire

The three-month voucher validity window is firm. If your installer cannot complete the work within this period, the voucher lapses and a new application must be made. Confirm your installer's availability and schedule before the voucher is applied for.

5. Not Getting Multiple Quotes

Prices for the same installation can vary by 3,000 to 5,000 pounds between installers. Always get at least three quotes and compare not just the price but also the scope of work, warranty terms and the equipment proposed.

6. Forgetting About Radiator Upgrades

Heat pumps operate at lower flow temperatures than gas boilers (typically 35 to 45 degrees Celsius versus 60 to 80). Some of your existing radiators may need to be upsized to deliver sufficient warmth. A good installer will include this in their quote, but check explicitly.

The April 2028 Deadline

The Boiler Upgrade Scheme has been confirmed to run until April 2028. This means you have time to plan properly, but it does not mean you should delay indefinitely. The grant budget is allocated annually, and while it has not been exhausted in previous years, uptake is accelerating as more homeowners become aware of the scheme.

Additionally, electricity tariffs and the ratio of electricity to gas prices may change over the coming years, affecting the running cost calculations that underpin the financial case for switching. Locking in a heat pump installation while the full 7,500 pound grant is available gives you the strongest financial position.

Using the Grant with Other Funding

The BUS grant can be combined with:

  • Local authority energy efficiency grants (where available)
  • ECO4 funding for insulation measures (if you are in an eligible household)
  • Green finance products such as green mortgages or home improvement loans

It cannot be combined with other central government grants for the same measure (for example, you cannot receive both a BUS voucher and a Social Housing Decarbonisation Fund grant for the same installation).

Use our heat pump calculator to estimate your net cost after the grant and potential long-term savings versus your current heating system.

Frequently Asked Questions

Can I apply for the Boiler Upgrade Scheme myself?

No. The application must be submitted by your MCS-certified installer through the Ofgem portal. You cannot apply directly as a homeowner. Your role is to choose an installer, agree the quote and provide consent for the application.

What happens if my BUS application is rejected?

Ofgem will notify your installer of the reason for rejection. The most common reasons are an invalid or expired EPC, missing insulation recommendations that have not been addressed, or incorrect property details. Once the issue is resolved, your installer can resubmit the application. There is no limit on the number of resubmissions.

Do I have to replace my gas boiler before I can apply?

No. You apply while your existing boiler is still operational. The heat pump replaces the boiler as part of the installation. Your installer will decommission the old boiler during the installation process. You do not need to remove it in advance.

Sources

For further reading

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