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 Boiler Upgrade Scheme, assume it will fund building-scale plant, find that it will not, and conclude there is no help at all. Both assumptions are wrong. BUS covers only small heat pumps — 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 heating, cooling and ventilation upgrade with the real numbers in front of you.

Key takeaway upfront

Commercial HVAC is funded through capital allowances, not grants. The £1m Annual Investment Allowance gives 100% relief for any business, and companies can add the 50% first-year allowance for special-rate plant on spend above it; full expensing, which covers main-rate plant only, does not normally apply to heating, ventilation and air-cooling plant. Eligible energy-intensive industrial and data-centre sites could historically access the Industrial Energy Transformation Fund, which closed to new applications in July 2025. The £7,500 Boiler Upgrade Scheme covers only small heat pumps and does not fund VRF, chillers or air handling units. Every dated figure here should be confirmed against the current position on gov.uk.

In this guide

• The honest headline: BUS is for small heat pumps only
• Annual Investment Allowance — the primary route
• Annual Investment Allowance — £1m at 100%
• The 50% first-year allowance
• Industrial Energy Transformation Fund — closed July 2025
• Climate Change Levy relief
• The 0% VAT relief and its limits
• Which route fits your business
• Frequently asked questions

The honest headline: BUS is for small heat pumps only

Let us be plain, because most competitor sites either imply a grant exists or dodge the question: the £7,500 Boiler Upgrade Scheme is a flat grant for heat pumps up to 45 kWth, not a general HVAC grant. It funds air-source and ground-source heat pumps in homes and non-domestic buildings in England and Wales, so a small business replacing a gas boiler with a heat pump may qualify. It does not fund VRF, chillers or air handling units, and building-scale heat pumps sit above its size limit. A facilities manager waiting for a grant for those 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.

The Annual Investment Allowance — the primary route

The Annual Investment Allowance is the main commercial HVAC funding route. For companies, the 50% first-year allowance applies to new, unused special-rate plant, which covers most heating, ventilation and air-cooling plant.

In practice, a company spending up to £1m a year on qualifying HVAC plant deducts the full cost against its taxable profits in the year of purchase under the Annual Investment Allowance. 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. Spend above the £1m limit can still attract the 50% first-year allowance (companies only), with the balance written down at 6% a year. Ancillary works may fall under different rates, and the main-pool 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.

The Annual Investment Allowance applies whichever HVAC plant you are buying — a VRF system, a central chiller, or a commercial heat pump — provided it is qualifying plant, 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%

The Annual Investment Allowance (AIA) gives 100% relief on up to £1m of qualifying plant and machinery spend per year. It matters most for unincorporated businesses (sole traders and partnerships), which cannot use the company-only 50% first-year allowance, and for any business whose HVAC spend falls within £1m. For most commercial HVAC projects, the £1m allowance comfortably covers the qualifying spend, delivering 100% first-year relief. Where a project exceeds £1m or mixes qualifying and non-qualifying elements, the interaction between the Annual Investment Allowance, the first-year allowances and writing-down allowances needs an accountant’s eye.

The 50% first-year allowance

The 50% first-year allowance for special-rate assets applies to companies only and to new, unused plant, with the balance written down at 6% a year. Because rates and scope change, 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 50% first-year allowance is for companies only and covers new, unused special-rate plant, which includes most heating, ventilation and air-cooling plant; it does not extend 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 — closed July 2025

The Industrial Energy Transformation Fund (IETF), operated by DESNZ until it closed in July 2025, 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.

It is now closed. GOV.UK records that, following the 2025 Spending Review, there will be no further extension of the fund, the second Phase 3 window will not take place and no successor fund is planned, though projects already committed are funded to completion. So it was available for eligible energy-intensive industry and is not a route for new projects; for a standard commercial office it never applied. 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

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

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

Your situation	Primary route
Company paying corporation tax, buying new HVAC plant	Annual Investment Allowance (100% up to £1m), plus the 50% first-year allowance on special-rate plant
Sole trader or partnership	£1m AIA (the 50% first-year allowance is for companies only)
Funding via lease or asset finance	Ownership decides who claims the allowance: confirm with your accountant and finance provider
Energy-intensive manufacturing / data centre with a qualifying process	IETF closed in July 2025 with no further rounds planned, so check 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, ask for a desk feasibility and a good contractor 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

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

Not for VRF, chillers or air handling units. The £7,500 Boiler Upgrade Scheme can fund a heat pump up to 45 kWth in a home or non-domestic building in England and Wales. Commercial HVAC is otherwise funded through the tax system: the Annual Investment Allowance (100% on up to £1m a year) and, for companies, the 50% first-year allowance for special-rate assets — heating, ventilation and air-cooling plant is usually special-rate, so full expensing does not normally apply. Eligible energy-intensive industrial sites could historically use the Industrial Energy Transformation Fund, which closed in July 2025. Confirm current rates on gov.uk.

How much is the Annual Investment Allowance actually worth?

For a company at the 25% main corporation-tax rate, each £1 deducted in the year of purchase saves up to 25p of tax, so a 100% allowance such as the Annual Investment Allowance is worth up to 25p per £1 spent; the 50% first-year allowance gives roughly half of that in year one, with the balance written down at 6% a year. The 50% first-year allowance has no upper cap. It applies to companies only; unincorporated businesses use the £1m Annual Investment Allowance. Confirm the treatment of your project with your accountant.

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

Possibly, for a small system: the £7,500 Boiler Upgrade Scheme can fund a heat pump up to 45 kWth in a non-domestic building in England and Wales; above that size it does not apply. Commercial electrification is funded through the Annual Investment Allowance and, for companies, the 50% first-year allowance for special-rate assets. Eligible energy-intensive industrial and data-centre sites could historically access the Industrial Energy Transformation Fund for fuel-switching, but it closed to new applications in July 2025 with no successor planned. For most commercial buildings the tax routes are the answer.

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Authoritative references: the government’s capital allowances guidance, including full expensing for main-rate plant, the Industrial Energy Transformation Fund collection (the fund closed in July 2025), and the Climate Change Levy rates on GOV.UK.