Boiler Upgrade Scheme (BUS) Guide: £7,500 ASHP Grant, Eligibility, Application Process and Installer Obligations

Summary

The Boiler Upgrade Scheme launched in April 2022 as the UK government's primary demand-side heat pump incentive for domestic and small commercial properties. It provides a straightforward capital grant — the customer does not pay the grant amount; the installer claims it and reduces the invoice accordingly.

For heat pump installers, BUS vouchers are the primary route through which customers can afford heat pump installations. Understanding the eligibility rules, the application timeline, and the installer obligations is essential for every heat pump installer.

Key Facts

• £7,500 for ASHP — air source heat pump grant (England and Wales)
• £7,500 for GSHP — ground source heat pump grant (and water source heat pumps)
• Biomass boilers removed — biomass boilers were previously included; removed from the scheme in later iterations; check current scheme documentation
• England and Wales only — BUS applies in England and Wales; Scotland has separate heat pump support (Home Energy Scotland grants and loans)
• Valid EPC required — the property must have a valid EPC (Energy Performance Certificate) issued within the last 10 years; the EPC must not include an outstanding recommendation to install loft insulation (where loft is present and accessible) or cavity wall insulation (where applicable)
• Fossil fuel replacement — the existing primary heating system must be fossil fuel: gas boiler, oil boiler, LPG boiler, or electric storage heaters; heat-only electric direct systems are also eligible (separate condition)
• MCS-certified installer mandatory — only MCS-certified installers (MCS 007 for heat pumps) can install and redeem BUS vouchers; the installer must be on the MCS installer database
• Voucher validity — BUS vouchers are valid for a defined period (originally 3 months; check current scheme rules); the installation must be completed and the voucher redeemed within the validity period
• No means testing — BUS is not means-tested; any homeowner meeting the eligibility criteria can apply regardless of income
• Second homes — second homes in England and Wales are eligible (subject to having a valid EPC and meeting other criteria)
• New build — new build properties are not eligible for BUS (the system is intended for retrofitting existing properties)
• Landlords — private landlords with domestic tenancies can apply (property must have an EPC; the grant is for the building, not the occupant)
• Grant paid to installer — the BUS grant is paid directly to the installer, not the customer; the installer reduces the customer's invoice by the grant amount; this is a legal requirement

Quick Reference Table: BUS Eligibility

Detailed Guidance

How the Application Process Works

Step 1: Customer checks eligibility The customer (homeowner or landlord) checks their EPC on the EPC register (epcregister.com). The EPC must:

• Be less than 10 years old
• Not include an outstanding recommendation for loft insulation (where loft exists and is accessible) or cavity wall insulation (where applicable — check the EPC recommendations section)

If the EPC is expired, a new EPC is required (cost: £60–£120). If the EPC includes outstanding insulation recommendations, these must be addressed first (or the customer can contest the recommendation if the insulation has already been installed).

Step 2: Customer applies for a BUS voucher The customer applies through Ofgem's BUS portal. The application requires:

• Property address
• EPC number
• Details of the existing heating system
• Chosen MCS-certified installer name and MCS number

Vouchers are usually issued within a few days of application. The voucher specifies the grant amount and the validity period.

Step 3: Installer completes the installation The MCS-certified installer carries out the heat pump installation fully compliant with MCS 007:

• Complete heat loss calculation
• Install heat pump per MCS 007 requirements
• Commission and test
• Issue MCS installation certificate (lodged on MCS database)
• Issue Electrical Installation Certificate (for the dedicated circuit)

Step 4: Installer redeems the voucher The installer redeems the BUS voucher through the Ofgem BUS portal. Required information:

• Voucher reference number
• MCS installation certificate number
• Installation address
• Heat pump make and model
• Date of installation

On successful redemption, the grant (£7,500) is paid directly to the installer by Ofgem within a defined payment period (typically 10–15 business days).

Step 5: Invoice to customer The installer invoices the customer for the full installation cost minus the £7,500 BUS grant. The invoice must show:

• Full installation price
• BUS grant amount (£7,500) deducted
• Net amount payable by customer

EPC Insulation Recommendations: The Key Barrier

The most common reason for BUS ineligibility is an outstanding EPC recommendation for loft or cavity wall insulation. If the EPC recommends either of these and they have not been installed, the BUS application will be rejected.

How to address this:

1. Check the EPC recommendations section carefully — it lists measures by category
2. If loft insulation is recommended: the customer must either install loft insulation (typically £300–£500 — much cheaper than losing the £7,500 grant) or obtain evidence that the loft already has adequate insulation
3. If cavity wall insulation is recommended: the customer must either install it (£500–£1,500 for a typical semi-detached) or provide evidence that the property's walls are not suitable for cavity wall insulation (solid walls, filled cavities, non-standard construction)

Cavity wall insulation suitability survey: Where the EPC recommends cavity wall insulation but the walls are already filled, solid, or otherwise unsuitable, a CIGA (Cavity Insulation Guarantee Agency) registered surveyor can confirm the walls are unsuitable. This confirmation can be submitted as part of the BUS application to remove the outstanding recommendation from the eligibility assessment.

Updated EPC: If insulation has been installed since the existing EPC was issued, a new EPC (updated to reflect the installed insulation) will remove the recommendation and restore eligibility.

Installer Obligations Under BUS

Grant paid to installer — not customer: The BUS framework requires the grant to be paid to the installer, not the customer. The installer then reduces the customer's invoice. The installer cannot simply pocket the grant — this is fraud and would result in removal from the MCS scheme and potential criminal liability.

MCS 007 compliance: All BUS installations must comply with MCS 007. If an audit reveals non-compliance (e.g., no heat loss calculation was performed, heat pump is significantly oversized, commissioning records are incomplete), the installer faces compliance action from the certification body and potential grant clawback.

Voucher redemption timeline: The voucher must be redeemed within its validity period (check current rules — validity has varied). If the installation is delayed and the voucher expires, the customer must apply for a new voucher. New vouchers are subject to current scheme availability — if the scheme's annual budget is exhausted, new vouchers may not be available until the next funding period.

Ongoing audit exposure: BUS-funded installations are included in the MCS audit pool. An installer who claims multiple BUS grants without adequate MCS 007 documentation is at higher risk of audit selection and findings.

BUS vs ECO4 and Other Schemes

BUS (Boiler Upgrade Scheme):

• Universal eligibility (no income means test)
• Any fossil fuel system replacement
• Applies to all property types (owned; private rented)
• England and Wales only

ECO4 (Energy Company Obligation):

• Means-tested: targeted at lower-income households and certain benefit recipients
• Funded by energy suppliers
• Includes insulation, heating, and renewables (including heat pumps)
• Can fully fund the heat pump installation for eligible households (no customer contribution)
• Not limited to BUS grant amount — full cost may be covered

Great British Insulation Scheme (GBIS):

• Separate from BUS; focuses on insulation
• Can address the EPC insulation recommendations that block BUS eligibility

For customers who qualify for ECO4, this may be more advantageous than BUS (full funding rather than a £7,500 partial grant). As an installer, being able to advise customers on all available schemes is a differentiator.

Commercial Properties

BUS for small non-domestic premises (small commercial, community buildings) was included in earlier iterations of the scheme. Check current Ofgem documentation for the current status of non-domestic BUS applications, as the scheme focus may have changed.

Frequently Asked Questions

The customer's EPC is 11 years old. Can they still apply for BUS?

No. The EPC must be less than 10 years old at the time of the BUS voucher application. The customer must commission a new EPC (typically £60–£120 from an accredited assessor). A new EPC may also update insulation recommendations if work has been done since the last assessment.

Can a customer apply for BUS if they also want to keep their gas boiler as a hybrid backup?

A hybrid heat pump system (heat pump + gas boiler backup) can qualify for BUS provided the heat pump is the primary heating system. The BUS documentation confirms this — "hybrid" installations are eligible. The heat pump must be the dominant heating source; the gas boiler is for backup/top-up only. Both the heat pump and the boiler must be serviced and maintained separately.

What happens if the installation fails an MCS audit after the BUS grant has been paid?

If an MCS audit finds the installation does not comply with MCS 007, the certification body will require remedial action. In serious cases, the grant payment may be subject to clawback by Ofgem. The installer bears the cost of remedial work; the customer's heat pump remains installed but the installer may face financial penalties.

My customer is in Scotland. Can they claim BUS?

No. BUS applies to England and Wales only. In Scotland, heat pump support is available through Home Energy Scotland (Scottish Government funded): interest-free loans and grants up to £7,500 (matching the BUS amount) for eligible properties. The customer should contact Home Energy Scotland (homeenergyscotland.org) for details.

Regulations & Standards

• Boiler Upgrade Scheme (BUS) Order 2022 — the statutory instrument establishing the BUS

• MCS 007 — installation standard for heat pumps; required for BUS compliance

• MCS 001 — installer standard; required for BUS eligibility

• Energy Performance of Buildings (England and Wales) Regulations 2012 — EPC validity and assessment requirements

• Ofgem BUS portal — voucher applications and scheme rules

• MCS installer database — mcscertified.com — installer registration and certificate lodging

• EPC register — epcregister.com — EPC validity check

• Home Energy Scotland — Scotland heat pump funding

• mcs 007 heat pump standard — MCS certification requirements for BUS eligibility

• heat pump sizing heat loss — heat loss calculation required by MCS 007

• air source heat pump installation — ASHP installation requirements

• heat pump commissioning checklist — commissioning records required for BUS redemption

• building regs part l heat pumps — EPC and SAP requirements alongside BUS