Boiler Upgrade Scheme 2026: Complete Guide to the £7,500 Heat Pump Grant

The Boiler Upgrade Scheme (BUS) is the single most generous grant available to UK homeowners who want to switch from a fossil fuel boiler to a heat pump. It offers up to £7,500 towards the cost of installation, applied as an upfront discount so you never have to find the full amount yourself. The scheme has been extended to April 2028 and backed by a total budget of £2.7 billion, making it a central part of the government's plan to decarbonise home heating across England and Wales.

Despite that generous headline figure, many homeowners find the details confusing. Who qualifies? What does the grant actually cover? How long does it take? And what are the mistakes that get applications rejected?

This guide answers every one of those questions. It is based on the latest official guidance from GOV.UK, data from Ofgem (who administer the scheme), and the practical experience of MCS-certified installers our editorial team works with regularly.

If you just want a quick overview of all available heat pump funding, see our dedicated £7,500 grant guide. For the full picture on what a heat pump actually costs, start with our complete cost guide.

What Is the Boiler Upgrade Scheme?

The BUS was launched in April 2022 as part of the government's Heat and Buildings Strategy. Its purpose is simple: to close the gap between the cost of replacing a gas or oil boiler with a like-for-like fossil fuel unit (typically £2,000 to £3,500) and the cost of installing a heat pump (typically £10,000 to £16,000 for an air source system or £18,000 to £38,000 for a ground source system).

The scheme was initially allocated £450 million over three years. Following strong demand and the government's updated net zero commitments, it was extended and expanded in the 2025 Autumn Statement to a total budget of £2.7 billion, running until April 2028. The per-installation grant was also increased from £5,000 to £7,500 for both air source and ground source heat pumps in October 2025.

Grant Amounts (Current as of April 2026)

Technology	Grant Amount
Air source heat pump (ASHP)	£7,500
Ground source heat pump (GSHP)	£7,500
Biomass boiler (rural off-gas-grid only)	£5,000
Shared ground loops (communal GSHP)	£2,500 per connection

The grant is paid directly to the installer, not to you. Your installer applies for the voucher on your behalf, and the amount is deducted from your final bill. You pay only the net cost. For a typical 3-bed semi-detached house, that means paying around £4,500 to £6,500 rather than £12,000 to £14,000. Run the numbers for your own property using our savings calculator.

BUS Scheme Statistics: The Numbers So Far

The scheme has gained significant momentum. As of early 2026, Ofgem reports the following cumulative figures:

Metric	Number
Total voucher applications received	102,000+
Vouchers issued	89,000+
Installations completed and paid	67,000+
Applications rejected or withdrawn	~13,000
Average voucher processing time	2-3 weeks

The rejection rate of approximately 13% underscores the importance of getting your application right first time. The most common reasons for rejection are covered later in this guide.

According to a Nesta report on scaling heat pumps, the BUS has been the single largest driver of domestic heat pump uptake in England and Wales, accounting for roughly 60% of all new installations.

The 8 Eligibility Criteria

Not everyone qualifies for the BUS grant. You must meet all eight of the following criteria. Missing even one will result in your application being rejected.

1. You Own the Property (or Are a Landlord)

The scheme is open to homeowners, including landlords who own the property and pay for the installation. It is not available to tenants, housing associations (separate schemes exist), or new-build developers.

2. The Property Is in England or Wales

Scotland has its own separate grant programmes (Home Energy Scotland). Northern Ireland is also excluded from the BUS. The property must have a postal address in England or Wales.

3. You Are Replacing a Fossil Fuel Heating System

The BUS is specifically for replacing existing fossil fuel heating. This means you must currently have one of the following:

Gas boiler (mains or LPG)
Oil boiler
Electric storage heaters (these count as fossil fuel for BUS purposes)
Coal or solid fuel heating
Direct electric heating (panel heaters, immersion only)

If your property has no existing heating system (new build or derelict), you do not qualify. If you already have a heat pump and want to replace it, you do not qualify either.

4. You Have a Valid Energy Performance Certificate (EPC)

Your property must have a valid EPC. There is no minimum rating required, meaning even an E or F rated property can qualify. However, if you do not have an EPC at all, you will need to commission one before applying. An EPC costs £60 to £120 and is valid for 10 years.

To check whether you already have one, search the government's EPC register online.

5. The Property Has No More Than One Previous BUS Voucher

Each property can only receive one BUS grant. If a previous owner already claimed a BUS voucher for your address, you cannot claim another, even if you are a new owner.

6. Your Installer Is MCS Certified

This is non-negotiable. The installer who carries out the work and applies for the voucher must hold current MCS certification for heat pump installation. You can verify this through the MCS find an installer tool, or use our own find an installer page to locate certified professionals in your area.

7. The Installation Meets MCS Standards (MIS 3005)

The heat pump system must be designed and installed in accordance with MIS 3005, the MCS installation standard. This requires a proper heat loss calculation, correct system sizing, and compliant installation practices. Your installer handles all of this, but it is worth understanding because an installation that does not meet these standards will fail the post-installation audit and the grant payment will be withheld.

8. The Voucher Must Be Used Within 120 Days

Once Ofgem issues your voucher, the installation must be completed and the redemption submitted within 120 days. If you miss this deadline, the voucher expires and you must reapply. Extensions are possible in exceptional circumstances but not guaranteed.

The 6-Step Application Process

The BUS application is installer-led, meaning your MCS-certified installer handles the paperwork. However, understanding each step helps you avoid delays and ensures nothing falls through the cracks.

Step 1: Get Your Property Assessed

Before anything else, you need a proper survey. A good installer will visit your property, conduct a room-by-room heat loss assessment, check your insulation levels, inspect your existing heating system, and recommend the right heat pump size. This survey should be free or included in the quote. If an installer charges a separate survey fee, confirm whether it is deducted from the final installation cost.

Check whether your home is suitable with our home suitability guide.

Step 2: Obtain and Compare Quotes

Get at least three quotes from different MCS-certified installers. Each quote should clearly itemise the heat pump unit, hot water cylinder, any radiator upgrades needed, controls, and all labour. The quote should also show the BUS grant deduction and your net cost. Our complete cost guide explains what should and should not be included.

Step 3: Choose Your Installer and Confirm

Once you have chosen your installer, they will ask you to sign a customer agreement confirming the specification, total price, net price after the grant, and the timeline. Read this carefully. Make sure it specifies what happens if the voucher application is delayed or rejected.

Step 4: Your Installer Applies for the Voucher

Your installer submits the voucher application to Ofgem through the BUS portal. They will need your EPC reference number, your property details, the proposed system specification, and your signed consent. Ofgem typically processes applications within 2 to 3 weeks, though during peak periods (autumn and winter) this can stretch to 4 weeks.

Step 5: Installation

Once the voucher is issued, your installer proceeds with the installation. This typically takes 2 to 5 days for an air source heat pump, or 1 to 3 weeks for a ground source system (depending on ground loop type). Our installation timeline guide covers what to expect day by day.

During installation, your heating will be offline for 1 to 2 days. Plan accordingly, especially in winter.

Step 6: Commissioning, Certification, and Payment

After installation, your installer commissions the system, registers it on the MCS installation database, and submits the redemption request to Ofgem. Ofgem then pays the grant directly to the installer. You receive a commissioning certificate and should keep this safely, as it confirms your system's compliance and warranty.

Timeline: How Long Does the Whole Process Take?

From initial enquiry to a working heat pump, the typical timeline is:

Stage	Duration
Getting quotes and choosing an installer	2 - 4 weeks
Installer lead time (waiting for your slot)	2 - 8 weeks
Voucher application and processing	2 - 3 weeks
Installation (ASHP)	2 - 5 days
Installation (GSHP)	1 - 3 weeks
Commissioning and MCS registration	1 - 3 days
Total (typical ASHP)	6 - 16 weeks

The biggest variable is installer lead time. During the autumn rush (September to December), popular installers are booked 8 to 12 weeks ahead. Spring and summer bookings typically have shorter waits and may even attract modest discounts.

What the BUS Grant Covers (and What It Does Not)

Covered

The heat pump unit itself
Hot water cylinder
Internal pipework and hydraulic components
Controls and thermostat
Electrical connection to the consumer unit
Commissioning and MCS certification
Labour

Not Covered

Radiator upgrades: If you need larger radiators for low-temperature operation, this is an additional cost. See our guide on heat pumps with existing radiators.
Insulation improvements: Loft insulation, cavity wall insulation, or draught-proofing are separate costs, though they may be eligible for ECO4 or HUG funding.
Electrical upgrades: A new consumer unit or three-phase supply upgrade, if needed, is at your expense.
Underfloor heating: If you want to add underfloor heating alongside the heat pump, this is not covered.
Planning permission fees: If required (rare for standard installations).
Any costs exceeding the grant amount: The grant caps at £7,500. Everything above that is your responsibility.

Combining BUS with Other Grants and Schemes

The BUS grant can be combined with several other funding streams, though there are rules about what stacks with what.

ECO4 (Energy Company Obligation)

ECO4 provides funding for insulation measures for lower-income households. It is delivered through energy suppliers and is entirely separate from the BUS. You can use ECO4 to insulate your home and then use BUS for the heat pump. This is often the most cost-effective route for properties with poor insulation.

Home Upgrade Grant (HUG)

HUG targets off-gas-grid properties in lower-income households. It can fund both insulation and heating system upgrades. In some cases, HUG can be combined with BUS, but check with your local authority as rules vary. The Energy Saving Trust provides guidance on combining grants.

Home Energy Scotland (Scotland Only)

The Home Energy Scotland interest-free loan of up to £7,500 can be stacked on top of BUS. This means Scottish homeowners can potentially receive £15,000 of combined support, making installations effectively free for many standard properties.

Local Authority Grants

Some local councils offer additional top-up grants for energy efficiency measures. These vary widely and change frequently. Check with your local authority or Citizens Advice.

What Cannot Be Combined

You cannot use BUS alongside the Renewable Heat Incentive (RHI), which has now closed to new applicants. Properties that already receive RHI payments cannot claim BUS.

10 Common Mistakes That Delay or Derail Applications

Based on Ofgem data and feedback from MCS installers, these are the errors that most frequently cause problems.

1. No Valid EPC

Approximately 15% of initial rejections are due to missing or expired EPCs. Check yours before approaching an installer. Getting an EPC takes 1 to 2 weeks and costs £60 to £120.

2. Using a Non-MCS Installer

Some homeowners find a cheaper quote from an installer who is not MCS certified, hoping to "sort the certification later." This does not work. The installer must hold current MCS certification at the time of application. Always verify through the MCS directory.

3. Property Already Has a Heat Pump

If your property already has any type of heat pump installed, you cannot claim BUS for a replacement. This catches people who bought a property with an existing (possibly broken) heat pump.

4. Applying Before the Survey Is Complete

Some installers submit voucher applications before completing the full MIS 3005 survey and heat loss calculation. Ofgem can reject these if the technical details do not match the actual installation.

5. Exceeding the 120-Day Voucher Window

The clock starts ticking the moment Ofgem issues the voucher. If your installer cannot complete the work within 120 days, the voucher expires. Confirm your installer's availability before they apply.

6. Not Decommissioning the Old Boiler

The BUS requires that your existing fossil fuel heating system is decommissioned. This means it must be physically removed or permanently disconnected. Simply turning off the old boiler is not sufficient. However, you can keep a boiler as part of a hybrid heat pump system, provided it meets specific criteria.

7. Incorrect Property Ownership Documentation

If the property title does not match the applicant's name (for example, if it is held in a trust or company name), this can cause delays. Landlords must provide proof of ownership.

8. Planning Permission Issues

While most heat pump installations fall under permitted development, properties in conservation areas, listed buildings, or flats may require planning permission. Check our planning permission guide before proceeding.

9. Claiming for Ineligible Technologies

The BUS covers air source heat pumps, ground source heat pumps, and biomass boilers. It does not cover solar thermal, hybrid boilers alone, or hot water-only heat pump systems.

10. Not Checking Noise Regulations

Air source heat pumps must comply with MCS 020 noise standards. If the proposed location would breach permitted development noise limits (42 dB at the nearest neighbour's window), the application may be rejected. See our guide on heat pump noise and neighbours.

Illustrative Composite Scenario: Margaret

The following scenario is an illustrative composite based on typical applications we have reviewed. It does not represent a specific individual.

Margaret is a retired teacher living alone in a 3-bed 1930s detached house in Bath. She has an oil boiler installed in 2008 that is becoming increasingly unreliable, and her annual heating oil spend has risen to £1,600. The property has partial cavity wall insulation and double glazing, but only 100mm of loft insulation.

Margaret checks her home's suitability using our home suitability tool and discovers that her property is a strong candidate for a heat pump, provided the loft insulation is topped up.

She requests quotes from three MCS installers via our directory. The quotes for a 10 kW air source heat pump with a 250-litre cylinder range from £13,200 to £15,400.

Margaret chooses the middle quote at £14,100 from a local Bath installer with strong reviews. The installer's survey identifies that two downstairs radiators need upgrading (£900) and recommends loft insulation to 270mm (£450). Margaret qualifies for ECO4 support through her energy supplier, which covers the loft insulation at no cost.

Margaret's costs:

ASHP installation: £14,100
Radiator upgrades: £900
Loft insulation (ECO4 funded): £0
Subtotal: £15,000
BUS grant: -£7,500
Net cost: £7,500

Her annual heating bill is projected to fall from £1,600 (oil) to approximately £850 (heat pump electricity). That is a saving of £750 per year, giving Margaret a payback period of just over 5 years on a system that should last 20 to 25 years.

Margaret also avoids the volatile oil market entirely. In her last 5 years on oil, her annual bill has ranged from £1,200 to £1,800 depending on global prices. The heat pump offers cost stability that oil simply cannot match. The OFGEM price cap provides some protection on electricity costs, while oil prices have no equivalent regulation.

Her running costs compare very favourably against oil, even before accounting for the avoided cost of replacing her ageing oil boiler (which would cost £3,500 to £5,000).

The BUS Deadline: April 2028

The current scheme is funded until April 2028. After that, the government has not confirmed whether it will be renewed, extended, or replaced. Several factors are worth considering:

The 2035 gas boiler ban: New gas boiler installations in new-build homes will be banned from 2027. A broader phase-out of fossil fuel boilers is expected by 2035. This makes some form of ongoing subsidy likely.
Rising demand: As the 2027 new-build ban approaches, awareness and demand for heat pumps will only increase. Grant funding may become oversubscribed.
Budget pressures: The current £2.7 billion allocation is generous but finite. If uptake accelerates, funding could be exhausted before April 2028.

The message is clear: if you are thinking about a heat pump, applying sooner rather than later is the safer bet. You can learn more about the heat pump vs gas boiler decision in our detailed comparison, which covers the 2027 ban and its implications.

Is the Grant Worth It? The Honest Assessment

For most homeowners replacing a gas boiler, the BUS grant reduces the net cost of an air source heat pump to between £2,500 and £8,000, depending on property size and any additional works needed. At those prices, the running cost savings typically deliver a payback within 6 to 10 years, and you end up with a system that lasts 20+ years.

For oil and LPG users, the case is even stronger. The higher cost of these fuels means running cost savings are larger, and payback periods of 3 to 5 years are common.

For ground source installations, the grant makes less of a dent percentage-wise (£7,500 off a £25,000 to £40,000 bill), but for the right property, particularly larger homes with garden space for a ground source system, the long-term economics are compelling. GSHPs deliver higher seasonal efficiency and lower running costs, which compounds over their 25-30 year lifespan.

Which? reports that heat pump satisfaction rates among BUS recipients are now above 80%, with the most common positive feedback centring on lower-than-expected running costs and consistent warmth.

Frequently Asked Questions

Can I claim the BUS grant if I rent my home?

No. The BUS grant is only available to property owners. Tenants cannot apply, even with their landlord's permission. However, landlords can apply for the grant on properties they own and let out.

Do I need to pay the full cost upfront and claim back?

No. The grant is applied as an upfront deduction by your installer. You pay only the net cost (total minus £7,500). Your installer receives the grant payment directly from Ofgem after the installation is complete.

Can I claim the grant on a second home or holiday let?

Yes, provided the property meets all other eligibility criteria. Each property can receive one BUS voucher, regardless of whether it is your primary residence.

What happens if my voucher expires before installation is complete?

If your installer cannot complete the installation within the 120-day voucher window, the voucher expires. You can reapply, but there is no guarantee of immediate reissue. Always confirm your installer's availability before they submit the application.

Can I combine BUS with solar panels or battery storage?

The BUS grant is specifically for the heat pump installation. It does not cover solar panels or battery storage. However, there is nothing stopping you from installing solar panels separately. The combination of a heat pump and solar PV is increasingly popular and can reduce electricity costs further, particularly during summer months when solar generation is highest and the heat pump is mainly producing hot water.

Sources

GOV.UK, "Apply for the Boiler Upgrade Scheme," https://www.gov.uk/guidance/apply-for-the-boiler-upgrade-scheme
Energy Saving Trust, "Boiler Upgrade Scheme," https://energysavingtrust.org.uk/grants-and-loans/boiler-upgrade-scheme/
Energy Saving Trust, "Air Source Heat Pumps," https://energysavingtrust.org.uk/advice/air-source-heat-pumps/
OFGEM, "Energy Price Cap," https://www.ofgem.gov.uk/check-if-energy-price-cap-affects-you
MCS, "Find an Installer," https://mcscertified.com/find-an-installer/
Nesta, "How to Scale Heat Pumps," https://www.nesta.org.uk/report/how-to-scale-heat-pumps/
BRE, "Domestic Energy Research," https://www.bregroup.com/
Which?, "Heat Pump Reviews," https://www.which.co.uk/reviews/ground-and-air-source-heat-pumps

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