The Boiler Upgrade Scheme (BUS) Explained: Grants for UK Heat Pump Installers and Homeowners

The Boiler Upgrade Scheme (BUS) is the UK government's demand-side grant for replacing fossil fuel heating with a heat pump. It sits apart from the public procurement notices that make up the rest of this site — it isn't a tender a contractor bids on — but it's directly relevant to RetrofitTenders' installer and contractor audience: a BUS-eligible property is a fundable, easier-to-close job in its own right, and understanding the scheme's eligibility rules and overlap with public retrofit funding helps a contractor price and plan work across both channels.

What the Boiler Upgrade Scheme is and who it's for

BUS is administered by Ofgem on behalf of the UK government and pays a grant, currently £7,500 for a property on mains gas or electric heating and £9,000 for an off-gas-grid property replacing oil or LPG heating, direct to an MCS-certified installer to reduce the upfront cost of an air source or ground source heat pump installation for the property owner. It is a demand-side subsidy aimed at owner-occupiers and private landlords replacing an existing fossil fuel system — a distinct mechanism from the supply-side public procurement contracts (local authority retrofit programmes, social housing decarbonisation frameworks) that most of this site's tender listings cover. For a heat pump installer, the practical relevance is straightforward: BUS-eligible jobs are grant-fundable work that doesn't depend on winning a public contract at all, and building the MCS certification and process familiarity needed to claim BUS grants smoothly is often the same capability a public retrofit tender evaluation is checking for.

Eligibility — property types, existing systems, and installer requirements

To qualify, the property must currently be heated by a fossil fuel system — mains gas, oil, or LPG — or, in some cases, direct electric resistance heating, and that system must be the one being replaced by the heat pump. The installer carrying out the work must be MCS-certified, and must also belong to an approved consumer protection code such as the Renewable Energy Consumer Code (RECC) or HIES, since Ofgem requires that as a condition of paying out on the voucher. As of 2026, the older requirement for a valid Energy Performance Certificate with no outstanding loft or cavity wall insulation recommendations has been removed — an EPC that flags further insulation work no longer blocks a claim, which was previously one of the more common reasons an otherwise-eligible property was turned away. Both owner-occupiers and private landlords (including portfolio and buy-to-let landlords) can claim, and there's no means test on the property owner.

Which property types are excluded

• New-build properties are excluded, other than genuine self-build or custom-build homes — a standard new-build development isn't eligible because building regulations already require low-carbon heating in new construction.
• Social housing let by a registered social landlord is excluded from BUS specifically. Social landlords retrofit their stock through separate public funding routes — principally the Social Housing Decarbonisation Fund, covered in the SHDF guide — rather than through this scheme.
• Park homes were effectively locked out for years because the scheme required an EPC, and most park homes have never had one; that requirement was removed for park homes specifically in 2026, and a recent fuel bill plus photographs of the existing heating system are now accepted as evidence instead.
• Non-domestic properties are eligible only up to a small scale — a maximum installation capacity of 45kWth — so most commercial buildings fall outside the scheme entirely.
• A property that has already received government funding or support for a heat pump or biomass boiler — for example under the closed Green Homes Grant — cannot claim BUS on top for the same measure. Funding under ECO4 for a different, separate measure on the same property doesn't block a BUS claim, but the same measure can't be paid for twice.

How BUS interacts with public retrofit tenders on this site

It's worth being precise about the overlap here, because it's easy to assume BUS simply stacks on top of public retrofit funding for the same property — it doesn't, since social landlords are excluded from claiming it at all. The real crossover for a contractor is operational rather than financial: a firm that wins public retrofit tender work — social housing stock upgrades funded through SHDF, or local-authority-run schemes for low-income private homes such as the Warm Homes: Local Grant — is building exactly the MCS certification, Retrofit Coordinator capability and process discipline (see the PAS 2035 guide for what that involves) that also lets it sell BUS-funded heat pump installs directly to private homeowners and landlords in the same area. In practice, a contractor already mobilised on a street or estate for a publicly funded social housing contract will often find privately owned properties nearby — a buy-to-let, an owner-occupied ex-council home — that are separately BUS-eligible, giving the same crew and supply chain a second, privately funded revenue line without a second mobilisation cost. Pricing a public retrofit tender bid with that adjacent BUS pipeline in mind, rather than treating public and private work as entirely separate streams, is a reasonable part of a contractor's commercial planning even though the grant itself never applies to the tendered property.

How to apply — the installer's step-by-step process

The homeowner doesn't apply directly or receive any money — the process runs through the installer:

1. Confirm MCS certification and eligibility. The installer checks the property's existing heating system, ownership type and EPC status against BUS rules before quoting.
2. Quote and agree the job. The customer is quoted the net cost after the grant is deducted, since the installer applies the discount upfront rather than the homeowner paying in full and being reimbursed.
3. Installer submits the voucher application through Ofgem's online portal, providing the property and EPC details and confirming the system being replaced.
4. Ofgem verification. Ofgem emails the property owner to confirm the installer is acting on their behalf — this step is a common place applications stall, since it depends on the homeowner replying promptly, so installers should flag it clearly when the application goes in.
5. Voucher issued and installation completed within the voucher's validity window, after which the installer claims the grant payment from Ofgem directly.

The most common rejection reasons in practice are incomplete or mismatched EPC data, an installer or consumer-code membership that isn't current at the time of application, and — less often now that the insulation-recommendation rule has been dropped — a property type that simply doesn't qualify, such as a new-build or a social-housing unit. Checking eligibility properly before submitting, rather than after a voucher is rejected, is the difference between a same-week turnaround and a stalled job. Contractors who want to find BUS-adjacent public contract work in the same areas they operate can use RetrofitTenders' free tender alerts to track new local authority and social housing retrofit notices as they publish.

Why this is worth tracking alongside public tender work

For a heat pump installer building a business around public retrofit contracts, BUS is easy to treat as background noise — a homeowner-facing scheme that doesn't touch the tender pipeline directly. In practice it's closer to a second, always-open sales channel that runs on the same certification and installation capability a public tender bid already has to demonstrate. A contractor that has invested in MCS certification, a named Retrofit Coordinator and a track record of documented, PAS 2035-compliant installs to win social housing or local authority retrofit work holds exactly what's needed to also market BUS-funded installs directly to private homeowners and landlords, without any additional accreditation. Treating the two as complementary — public contract work for pipeline volume and predictability, BUS-funded private jobs for margin and flexibility around it — is a more realistic way to plan a growing retrofit business than treating either channel in isolation.