BUS Grant for Heat Pumps 2026: Eligibility and £7,500 Subsidy

Why this topic matters

--- meta_title: "BUS Grant for Heat Pumps 2026: Eligibility, £7,500 Subsidy and Hybrid Rules" meta_description: "UK guide to the 2026 Boiler Upgrade Scheme heat pump grant: who qualifies, £7,500 subsidy amounts, 4 kW vs 6 kW sizing, hybrid heat pump eligibility and quote checks." featured_image_alt: "Air source heat pump installed outside a UK home as part of a low-carbon heating upgrade" author: "Kilowatts UK Renewable Heating Editorial Team" last_reviewed: "July 2026" ---

# BUS Grant for Heat Pumps 2026: Eligibility, Subsidy Amounts and Hybrid System Questions

BUS grant heat pump 2026 eligibility in brief

In 2026, the Boiler Upgrade Scheme, usually shortened to BUS, is expected to remain a £7,500 grant for eligible air source and ground source heat pumps in England and Wales. The grant is not based on heat pump size, so an eligible 4 kW air source heat pump and an eligible 6 kW air source heat pump receive the same subsidy.

• The main eligibility issues are:
• Whether the property is in England or Wales.
• Whether the installation replaces an eligible fossil-fuel or direct-electric heating system.
• Whether the heat pump is installed by an MCS certified installer using eligible equipment.
• Whether the system is designed as the property’s main heating system.
• Whether the installation is within the scheme’s capacity and property rules.
• Whether the voucher is applied for and redeemed correctly through Ofgem.

The scheme is currently planned to run until 2028, but 2026 applications should always be checked against the live GOV.UK Boiler Upgrade Scheme guidance and Ofgem BUS rules before committing to an installation. Grant values, evidence requirements and administrative rules can change. The installer normally applies for the voucher, claims the grant from Ofgem, and deducts the value from the customer’s quote or invoice. Homeowners should not usually expect to receive the BUS grant as a cash payment. The important distinction is between eligibility and suitability. A property may meet the scheme rules but still be expensive or awkward to convert. Equally, a heat pump could be technically sensible but fail the grant rules if it is installed as a hybrid system with a gas, oil or LPG boiler retained for routine heating.

Who can usually qualify for the Boiler Upgrade Scheme

The BUS applies to homes and some non-domestic buildings in England and Wales. It is not available in Scotland or Northern Ireland, where separate support schemes and rules apply.

The property normally needs a valid Energy Performance Certificate. Earlier versions of the scheme placed more emphasis on outstanding insulation recommendations, but the live 2026 rules should be checked because EPC and evidence requirements have changed during the life of the scheme.

The installation must use an eligible low-carbon heating product and be installed by an MCS certified installer. MCS certification matters because BUS is not simply a discount on equipment; it is a grant for a qualifying installed system. The heat pump must usually replace an existing fossil-fuel or direct-electric heating system. This can include:

• A mains gas boiler.
• An oil boiler.
• An LPG boiler.
• Coal or other fossil-fuel heating.
• Direct electric heating.
• Typical eligible situations include:
• An oil-heated house replacing the oil boiler with an air source heat pump.
• A gas-heated home replacing the gas boiler with a correctly sized heat pump.
• A direct-electric property moving to a full heat pump heating system.
• A self-build home that meets the scheme’s self-build evidence requirements.
• A rented property where the landlord, tenant permissions and installation meet the scheme rules.
• A qualifying non-domestic building replacing eligible existing heating.

The new system must be designed as the property’s main heating system rather than as a small add-on intended only to reduce boiler use. New-build homes are generally not eligible, although self-build and custom-build homes can be treated differently if they meet the evidence requirements. Flats, park homes, listed buildings and homes in conservation areas can sometimes qualify, but they often need extra checks around outdoor unit siting, planning, lease conditions, freeholder consent, access and noise.

How the BUS grant is applied to a heat pump installation

The homeowner does not usually receive the BUS grant directly. In most cases, the installer applies for the BUS voucher, the property owner confirms consent to Ofgem, and the grant is deducted from the installation price.

• A practical BUS process usually looks like this:
• [Survey](https://kilowatts.uk/booking/?kwrf=8SA53&kwpid=6&kwlid=9): The installer checks the property, heating system, outdoor unit location, cylinder space, electrical supply and heat loss.
• Quote: The installer provides a price that should clearly show the total cost before and after the BUS grant.
• Voucher application: The installer applies to Ofgem for the BUS voucher.
• Customer consent: The homeowner or property owner confirms that they understand and approve the application.
• Installation: The system is installed, commissioned, registered and handed over under the scheme rules.
• Grant claim: The installer claims the grant and the customer pays the remaining balance shown in the agreed quote.

A good quote should make the grant treatment clear. You should be able to see whether the £7,500 has already been deducted, whether there are excluded works, and whether electrical upgrades, radiator changes, cylinder work, oil tank removal, scaffolding or making-good costs are included. Do not rely on a verbal promise that “the grant is included”. Ask for the pre-grant price, the BUS deduction and the customer balance to be shown in writing.

How much is the BUS grant for heat pumps in 2026

The main heat pump BUS grant is £7,500 for an eligible air source heat pump and £7,500 for an eligible ground source heat pump. Shared ground loop ground source systems can also qualify where they meet the scheme rules.

Biomass boilers have a separate £5,000 grant, but biomass support is limited to eligible rural properties that are not connected to the gas grid. Biomass is not the same as a heat pump grant and should be assessed under its own BUS criteria.

The heat pump grant is fixed. It does not increase because the heat pump is larger, and it does not reduce because the unit is smaller. This is particularly important when comparing a 4 kW and 6 kW heat pump. For example, if both systems are eligible standalone air source heat pump installations, the BUS grant is the same £7,500. The final customer price may still differ because the equipment, hot water cylinder, emitters, pipework, electrical work and installation complexity may differ. Indicative UK air source heat pump installation prices vary widely by property and specification. Simple installations can be materially cheaper than complex homes needing radiator upgrades, cylinder changes, new pipework or electrical work. Ground source heat pump installations are usually more expensive than air source systems because of ground loops, trenches, boreholes, manifolds and reinstatement. For buyer comparisons, the useful figure is not the grant alone. It is the fully installed price after grant, with all required works included.

4 kW versus 6 kW heat pumps and the hybrid system question

For the query “BUS subsidy for a 4 kW versus 6 kW hybrid heat pump in 2026”, the short answer is that the kW size is not the deciding factor.

A 4 kW eligible standalone air source heat pump and a 6 kW eligible standalone air source heat pump would receive the same £7,500 BUS grant. A 4 kW or 6 kW hybrid heat pump that keeps a gas, oil or LPG boiler as part of the routine space-heating system would normally not qualify.

A hybrid heat pump usually means the heat pump works alongside a boiler. That may reduce fossil fuel use, and it can be a pragmatic option where a full low-temperature retrofit is difficult. However, BUS is intended to support a low-carbon heating system that replaces the previous fossil-fuel or direct-electric system, not one that leaves a boiler in service for normal heating loads. This means a cheaper hybrid proposal can be misleading if it is shown beside a BUS-funded standalone system. The hybrid may have a lower upfront installation cost, but it will usually lose the £7,500 grant and will continue to use fossil fuel. The better comparison is the total installed cost after grant, expected seasonal efficiency, fuel use, comfort, carbon reduction and whether the system can meet the home’s full heat demand. Be cautious with terms such as “hybrid-ready”, “boiler assisted”, “bivalent” or “backup boiler”. They can mean different things in sales material. For BUS eligibility, the practical question is whether the heat pump is the standalone main heating system or whether a fossil-fuel boiler remains part of the designed heating strategy. An immersion heater in a hot water cylinder, defrost function or emergency electrical backup is not the same as retaining a gas or oil boiler for normal heating. The installer should explain exactly what is included and how the system is intended to operate.

Why heat pump size should be based on heat loss rather than boiler size

A heat pump should be sized from a room-by-room heat loss calculation, not from the size of the existing boiler. Many UK boilers are much larger than the home’s actual space-heating demand, especially combi boilers sized for hot water rather than central heating. A 24 kW gas boiler does not mean the home needs a 24 kW heat pump.

Typical domestic air source heat pumps in the UK are often around 4 kW to 12 kW, but the right size depends on the building. Smaller flats and efficient small homes may need around 4 kW to 6 kW. Medium houses may need around 6 kW to 10 kW. Larger, leakier or rural homes may need 10 kW or more.

• The correct size depends on several design factors:
• The property’s heat loss at the local design outdoor temperature.
• The insulation level and draught proofing of the building.
• The radiator or underfloor heating capacity at low flow temperatures.
• The hot water cylinder size and recovery requirement.
• The available electrical supply and outdoor unit location.
• The way the occupants use heating and hot water.
• The manufacturer’s heat output at cold outdoor temperatures, not just mild test conditions.

A 4 kW heat pump may be suitable for a small, well-insulated property but too small for a typical detached or poorly insulated house. A 6 kW unit may suit some small to medium homes but still be inadequate where heat loss is high. Undersizing can lead to comfort complaints, long recovery times and excessive use of backup heaters. Oversizing can increase cost, cause cycling and reduce efficiency. Neither outcome is good value simply because the BUS grant is available. Installers should also check heat output at low outdoor temperatures. Some headline heat pump ratings are quoted at milder test conditions, while UK heating design conditions can be below 0°C in many areas. Output in cold weather is what matters for comfort.

What affects the real cost after the grant

The grant is fixed, but the customer contribution is not. Two homes receiving the same £7,500 BUS grant can have very different final costs because the installation work may be very different.

• Common cost drivers include:
• Heat pump type: Ground source systems usually cost more than air source systems because of ground loops, trenches or boreholes.
• Radiator upgrades: Larger radiators may be needed to heat rooms at lower flow temperatures.
• Hot water cylinder work: Homes with combi boilers often need space for a heat pump-compatible hot water cylinder.
• Pipework limitations: Microbore pipework or restricted routes can affect flow rates and system design.
• Electrical supply: Older homes may need [consumer unit work](https://kilowatts.uk/services/residential/general-electrical-work/residential-fuse-box-upgrades/), wiring upgrades, DNO checks or main fuse changes.
• Outdoor unit siting: Long pipe runs, poor access, noise constraints and difficult condensate drainage can add complexity.
• Removal work: Oil tank removal, boiler decommissioning, asbestos risk, flue removal and making good can all affect the quote.
• Controls and commissioning: Weather compensation, zoning, room sensors and user handover all affect real performance.
• Building condition: Draughts, poor loft insulation, weak glazing or uninsulated pipe runs can increase heat demand.

The cheapest eligible quote is not always the best value. A low price can be undermined by high flow temperatures, undersized emitters, poor controls, a mismatched cylinder or weak commissioning. A more detailed quote that explains design assumptions is usually more useful than a simple equipment list.

Technical suitability matters even when the grant rules are met

BUS eligibility does not automatically mean the home is ready for an efficient heat pump. The survey should test whether the home can be heated comfortably at sensible flow temperatures. Larger radiators, underfloor heating and good fabric performance all help because lower flow temperatures generally improve efficiency.

Seasonal Coefficient of Performance, often shortened to SCOP, is the average heat output divided by electricity input across the heating season. A SCOP of 3 means the heat pump delivers 3 kWh of heat for each 1 kWh of electricity used on average. Typical UK air source heat pump SCOP values are often around 2.5 to 4.0, depending heavily on design, flow temperature, climate, usage and commissioning.

• Real-world points that are often missed include:
• Condensate drainage and defrost water.
• Access for servicing.
• Outdoor unit airflow.
• Noise at neighbouring windows and boundaries.
• Pipe insulation.
• Water quality and system flushing.
• Correct antifreeze or frost protection strategy.
• User handover and control settings.

Enclosing an outdoor unit to hide it can reduce airflow and cause faults. Leaving old radiator sludge in the system can damage components. Setting the heat pump to run like an on-off gas boiler can reduce performance. Weather compensation is particularly important. It adjusts the flow temperature according to outdoor temperature, allowing the system to run cooler in mild weather and warmer only when needed. A homeowner should be shown how the controls work, what the normal running pattern looks like, and when an immersion heater should or should not be used.

When a BUS-funded heat pump may not be the right choice

A BUS-funded heat pump is strongest where heat loss is manageable, the property has space for equipment, the outdoor unit can be sited sensibly, and the owner is comfortable with low-temperature heating operation. Oil, LPG and direct-electric homes can be strong candidates, provided the technical design is sound.

It may be less suitable where the building has severe insulation gaps, no realistic cylinder location, difficult outdoor unit siting, lease or planning restrictions, or electrical supply constraints that have not been resolved.

Gas-heated homes can be eligible, but running cost savings are not guaranteed because they depend on electricity prices, gas prices, system efficiency and heat demand. A well-designed heat pump can reduce carbon emissions substantially, but the financial case should be tested against the household’s actual usage and tariff options. Hybrid systems can still have a role outside BUS. They may suit homes where a full retrofit is not practical immediately, where radiator upgrades would be disruptive, or where the owner wants to reduce boiler use without replacing the whole heating system. The trade-off is that hybrids normally do not qualify for BUS and still rely on fossil fuel.

• The decision should separate three questions:
• Does the property qualify under the live BUS rules?
• Is the proposed heat pump system technically well designed?
• Does the final cost, running pattern and disruption make sense for the household or business?

What to check before accepting a BUS heat pump quote

Before accepting a quote, ask the installer to explain the eligibility route, the heat loss calculation and the design assumptions. Do not rely only on the headline heat pump size or the grant value.

• A robust proposal should cover:
• The room-by-room heat loss calculation and design outdoor temperature.
• The proposed heat pump size and the reason for choosing it.
• The proposed flow temperature and expected seasonal performance.
• Which radiators, pipework or cylinders need changing.
• Whether the system is standalone or hybrid.
• How the £7,500 BUS grant is shown in the quote.
• Any electrical, planning, DNO, access or making-good assumptions.
• The outdoor unit location and noise considerations.
• The hot water cylinder size and immersion heater controls.
• The commissioning settings and handover documents you will receive.
• Warranty, servicing and aftercare arrangements.

You should also confirm that the installer is MCS certified and that the product and installation meet the scheme requirements. BUS cannot normally be combined with another public grant for the same installation cost, although private finance or savings may be used for the remaining balance. If a quote is unclear, ask for it to be rewritten before paying a deposit. The BUS grant is valuable, but it should not be used to rush a poor design decision.

Author and review note

This guide was prepared by the Kilowatts UK Renewable Heating Editorial Team, drawing on UK heat pump survey, electrical upgrade and low-carbon home energy planning experience. It is intended as practical buyer guidance, not a substitute for a site survey, MCS design, Ofgem approval or legal advice on planning, leases or grant eligibility.

Scheme rules can change. Always check the current GOV.UK, Ofgem and MCS requirements before signing a contract.

Sources and further reading

The following points summarise the most important takeaways:

• [MCS

  Boiler Upgrade Scheme information](https://mcscertified.com/boiler-upgrade-scheme/)

• [Ofgem

  Boiler Upgrade Scheme](https://www.ofgem.gov.uk/environmental-and-social-schemes/boiler-upgrade-scheme-bus)

• [GOV.UK

  Apply for the Boiler Upgrade Scheme](https://www.gov.uk/apply-boiler-upgrade-scheme)

• [GOV.UK 2

  Heat pumps explained](https://www.gov.uk/government/publications/heat-pumps-explained/heat-pumps-explained)

Bottom line for BUS grant heat pump 2026 decisions

For 2026, the key point is simple: BUS is a fixed grant for eligible low-carbon heating installations, not a capacity-based subsidy. A 4 kW and 6 kW eligible standalone air source heat pump receive the same £7,500 grant, while 4 kW and 6 kW hybrid heat pumps with a retained fossil-fuel boiler would normally receive no BUS grant.

The right system size should come from a proper heat loss design, not from the existing boiler size or a grant comparison. Check the live scheme rules, insist on a clear before-and-after grant quote, and make sure the design can heat the whole property efficiently before treating BUS eligibility as a reason to proceed.