How to Fund a Commercial HVAC Upgrade — the Real Routes

The single most common funding mistake in commercial HVAC is assuming there is a grant. Facilities managers hear about the £7,500 domestic Boiler Upgrade Scheme, expect a commercial version, find none, and conclude there is no help at all. Both assumptions are wrong. There is no commercial BUS — but there is a genuine funding playbook through the tax system that turns HVAC capital into relief. This guide maps the routes that actually apply, honestly and with the caveats each one carries, so you can plan a commercial HVAC upgrade with the real numbers in front of you.

Key takeaway upfront

Commercial HVAC is funded through capital allowances, not grants. Full expensing gives companies a 100% first-year deduction on qualifying new plant, the £1m Annual Investment Allowance covers other businesses and items outside full expensing, and a new 40% first-year allowance from 1 January 2026 extends first-year relief further. Eligible energy-intensive industrial and data-centre sites could historically access the Industrial Energy Transformation Fund, but its windows are winding down. The domestic £7,500 Boiler Upgrade Scheme does not apply. Every dated figure here should be confirmed against the current position on gov.uk.

In this guide

• The honest headline: no commercial BUS
• Full expensing — the primary route
• Annual Investment Allowance — £1m at 100%
• The new 40% first-year allowance
• Industrial Energy Transformation Fund — winding down
• Climate Change Levy relief
• The 0% VAT relief and its limits
• Which route fits your business
• Frequently asked questions

The honest headline: no commercial BUS {#no-bus}

Let us be plain, because most competitor sites either imply a grant exists or dodge the question: the £7,500 Boiler Upgrade Scheme is domestic only. It funds air-source and ground-source heat pumps in homes in England and Wales, up to 45 kWth. There is no commercial equivalent. A facilities manager waiting for a commercial BUS is waiting for something that does not exist.

That is not bad news, though — it just means the funding is structured differently, through the tax system rather than a grant. And for a company paying corporation tax, the tax route can be worth a great deal. The rest of this guide sets out how.

Full expensing — the primary route {#full-expensing}

Full expensing is the main commercial HVAC funding route. For companies paying UK corporation tax, it gives a 100% first-year deduction on qualifying new, unused plant and machinery — and HVAC plant qualifies. There is no upper cap, and it was made permanent from April 2026.

In practice, a company spending on qualifying new HVAC plant deducts the full cost against its taxable profits in the year of purchase. At the 25% main corporation-tax rate, that is worth up to 25p of tax saved for every £1 spent — turning a capital project into a substantial tax reduction in year one. It is companies only: sole traders and partnerships use the Annual Investment Allowance and the new first-year allowance instead. Ancillary works may fall under different rates, and the main writing-down allowance was reduced to 14% from April 2026, so confirm the treatment of your specific project with your accountant and against gov.uk.

Full expensing applies whichever HVAC plant you are buying — a VRF system, a central chiller, or a commercial heat pump — provided it is new and qualifying, so it is the route that most often carries the bulk of a commercial HVAC investment. Our sibling resource on commercial heat pumps also walks through the funding for electrified heat, which is worth reading alongside this if a heat pump is part of your upgrade.

Annual Investment Allowance — £1m at 100% {#aia}

The Annual Investment Allowance (AIA) gives 100% relief on up to £1m of qualifying plant and machinery spend per year. It matters for two groups: unincorporated businesses (sole traders and partnerships) that cannot use full expensing, and companies buying items that fall outside full expensing. For most commercial HVAC projects, the £1m allowance comfortably covers the qualifying spend, delivering the same 100% first-year relief. Where a project exceeds £1m or mixes qualifying and non-qualifying elements, the interaction with full expensing and writing-down allowances needs an accountant’s eye.

The new 40% first-year allowance {#fya}

From 1 January 2026 a new 40% first-year allowance extends first-year relief further, including to unincorporated businesses and to leased assets — an area that full expensing did not reach. This broadens who can claim meaningful first-year relief on HVAC plant. Because it is a recent measure, confirm the current rate, scope and any conditions on gov.uk before relying on it, and note it sits alongside the reduced 14% main writing-down allowance from April 2026.

Callout — leased and financed plant. The new 40% first-year allowance is notable for extending first-year relief to leased assets. If your HVAC upgrade is funded through asset finance or a lease, this may change the tax picture materially — a point worth raising with your accountant early.

Industrial Energy Transformation Fund — winding down {#ietf}

The Industrial Energy Transformation Fund (IETF), operated by DESNZ, historically offered grants of 30–50% for industrial fuel-switching and energy-efficiency projects — including gas-boiler-to-heat-pump conversions and waste-heat recovery — at eligible industrial sites and data centres in eligible SIC codes. It was never for ordinary office air conditioning or comfort cooling.

Crucially, it is winding down. Following the 2025 Spending Review, no further extension is planned and the second Phase 3 window will not take place, though committed projects are funded to completion. So treat it honestly: it was available for eligible energy-intensive industry, and any live status must be confirmed on gov.uk rather than assumed. For a manufacturing or data-centre site with a qualifying process, it may still be worth checking; for a standard commercial office it does not apply. Where the upgrade is also driven by lettability rather than a process, our guide to MEES and commercial HVAC sets out how the compliance case and the funding case interact.

Climate Change Levy relief {#ccl}

The Climate Change Levy (CCL) is not a grant but a running-cost lever. It adds cost to both electricity and gas — the main rate from 1 April 2026 is 0.801p/kWh — and energy-intensive sectors that sign a Climate Change Agreement (CCA) and meet efficiency targets receive large discounts: from 1 April 2026, 92% relief on electricity and 89% on gas. Efficient HVAC lowers energy use and therefore CCL exposure, and eligible sectors can cut the levy sharply through a CCA. Confirm current rates and sector eligibility on gov.uk.

The 0% VAT relief and its limits {#vat}

A zero rate of VAT applies to the installation of qualifying energy-saving materials — heat pumps, solar, heating controls and more — in Great Britain until 31 March 2027, after which it reverts to 5%. But the relief is targeted at residential accommodation and qualifying charitable buildings, so it does not blanket-cover ordinary commercial premises. It is relevant to mixed-use owners (the residential element), charity-occupied buildings and any residential portion — not a standard commercial office. State that caveat honestly and confirm scope on the gov.uk notice before relying on it.

Which route fits your business {#which-route}

Your situation	Primary route
Company paying corporation tax, buying new HVAC plant	Full expensing (100% first-year deduction)
Sole trader or partnership	£1m AIA, plus the new 40% FYA
Funding via lease or asset finance	New 40% first-year allowance (confirm scope)
Energy-intensive manufacturing / data centre with a qualifying process	Check IETF status (winding down) + CCA relief
Mixed-use building with a residential element	0% VAT on the qualifying residential portion (to 31 March 2027)

The right route depends on your business structure and the plant, so the practical step is to model the funding alongside the project cost — see our cost guide for the capital ranges and the grants and funding page for the full detail. When you are ready, request a free desk feasibility and we will map the funding that genuinely applies to your building and business, and tell you plainly where a route does not fit.

Frequently asked questions {#faqs}

Is there a grant for commercial HVAC or a commercial Boiler Upgrade Scheme?

No. The £7,500 Boiler Upgrade Scheme is domestic only, and there is no commercial equivalent. Commercial HVAC is funded through the tax system: full expensing (100% first-year deduction for companies, permanent from April 2026), the £1m Annual Investment Allowance for other businesses, and a new 40% first-year allowance from 1 January 2026. Eligible energy-intensive industrial sites could historically use the winding-down Industrial Energy Transformation Fund. Confirm current rates on gov.uk.

How much is full expensing actually worth?

For a company at the 25% main corporation-tax rate, full expensing is worth up to 25p of tax saved for every £1 spent on qualifying new plant, because the full cost is deducted against taxable profits in the year of purchase. HVAC plant qualifies, and there is no upper cap. It applies to companies only; unincorporated businesses use the £1m Annual Investment Allowance and the new 40% first-year allowance. Confirm the treatment of your project with your accountant.

Can I get funding to replace gas boilers with a heat pump commercially?

Not through a grant like the domestic Boiler Upgrade Scheme, which does not apply. Commercial electrification is funded through full expensing, the AIA and the new 40% first-year allowance. Eligible energy-intensive industrial and data-centre sites could historically access the Industrial Energy Transformation Fund for fuel-switching, though its windows are winding down, so confirm current status on gov.uk. For most commercial buildings the tax routes are the answer.

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Authoritative references: the government’s capital allowances and full expensing guidance, the Industrial Energy Transformation Fund collection, and the Climate Change Levy rates on GOV.UK.