What Is the Annual Investment Allowance (AIA)?
The Annual Investment Allowance (AIA) is a capital allowance that lets you claim 100% tax relief on qualifying plant and machinery costs up to a set annual limit. For the 2025/26 tax year, that limit is £1 million [1]. This means you can deduct the full cost of eligible assets from your taxable profits in the year you buy them, rather than spreading the relief over several years.
For UK landlords, this is particularly relevant if you run your property business through a limited company or if HMRC treats your letting activity as a trade (for example, furnished holiday lettings before the regime was abolished in April 2025, or certain serviced accommodation operations). Most residential landlords letting on standard assured shorthold tenancies cannot claim capital allowances because their activity is treated as investment, not a trade. However, commercial property landlords and those with substantial property businesses may qualify.
How Much Is the Annual Investment Allowance in 2025?
The AIA is set at £1 million per year for qualifying expenditure on plant and machinery [2]. This applies to all businesses regardless of size, so a sole trader landlord with a single commercial unit can claim the same £1 million limit as a large property company [2].
If your accounting period is shorter than 12 months, the allowance is proportionally reduced. For example, if your accounting period is 9 months, the AIA will be 9/12 x £1,000,000 = £750,000 [1]. You can only claim AIA in the period you bought the item [1].
What Qualifies for the Annual Investment Allowance?
The AIA covers most plant and machinery used in your property business. This typically includes:
- Fixtures and fittings in commercial properties (heating systems, air conditioning, lifts)
- Kitchen equipment in furnished lets or HMOs
- Furniture and white goods in furnished properties
- Solar panels and other energy-efficient installations
- Electric vehicle charge points (which also qualify for a separate 100% first-year allowance until April 2027) [3]
- Office equipment used for managing your property portfolio
However, there are important exclusions. The AIA is not available for expenditure on cars, assets used for leasing, or assets provided for the use of a director or employee [2]. It also does not apply to assets that are not used wholly and exclusively for the purposes of the trade [2].
When Can You Claim the AIA?
The date you bought the item determines when you can claim. According to HMRC guidance, the date of purchase is: when you signed the contract, if payment is due within less than 4 months; or when payment is due, if it is due more than 4 months later [1].
If you buy something under a hire purchase contract, you can claim for all payments you will make under the contract once you start using the item [1]. This can be useful for landlords financing larger purchases like commercial heating systems or lifts.
You cannot claim AIA for items bought in the final accounting period if your business closes [1]. Similarly, the AIA is not available for expenditure incurred before the business starts to trade [2].
Changes Coming in 2026: New 40% First-Year Allowance
From 1 January 2026, the government is introducing a new 40% first-year allowance for main rate assets [3]. This will apply to new expenditure on eligible assets, including most plant or machinery for leasing, but will exclude second-hand assets, cars, and assets leased overseas [3].
At the same time, the main rate of writing-down allowance for plant or machinery is reducing from 18% to 14% [3]. This change takes effect from 1 April 2026 for corporation tax and 6 April 2026 for income tax [3]. The government expects this reduction to raise £1.5 billion in 2029-30 [4].
For landlords, this means that from April 2026, if you cannot claim the full AIA in one year, the remaining balance will attract a lower annual writing-down allowance than before. Planning your capital expenditure timing becomes more important.
How Does the AIA Apply to Different Property Types?
Commercial Property Landlords
If you let commercial property and your letting activity is treated as a trade, you can claim the AIA on qualifying plant and machinery within the building. This includes items like heating, ventilation, and electrical systems. The £1 million limit applies per accounting period [1].
HMO and Serviced Accommodation Landlords
HMOs and serviced accommodation operations are often treated as trades by HMRC, particularly if you provide significant services (cleaning, meals, laundry). In these cases, you can claim the AIA on furniture, kitchen equipment, and other plant and machinery. However, with the abolition of the Furnished Holiday Lettings regime from April 2025, the distinction between trading and investment activity has become more complex. You should seek specialist advice on your specific circumstances.
Residential Landlords (Standard Lets)
Most residential landlords letting on standard tenancies cannot claim capital allowances because their activity is treated as investment, not a trade. Instead, you claim replacement of domestic items relief for furniture and appliances. If you are unsure whether your letting activity qualifies as a trade, speak to a specialist property accountant.
Practical Tips for Claiming the AIA
Keep clear records of all capital expenditure, including contracts, invoices, and payment dates. The AIA is claimed in your tax return or company accounts for the period in which you bought the item [1].
If you are planning significant capital expenditure, consider timing your purchases to maximise the AIA. With the £1 million limit, most landlords will not exceed the threshold, but if you are undertaking a major refurbishment of a commercial property, you may need to spread purchases across accounting periods.
Remember that the AIA is not available for cars [2]. If you need a vehicle for your property business, you will need to claim capital allowances through the standard writing-down allowance pool instead.
How a Property Accountant Can Help
Navigating capital allowances can be complex, particularly with the changes coming in 2026. A specialist property accountant can help you identify qualifying expenditure, plan the timing of purchases, and ensure you claim the maximum relief available.
At Property Tax Partners, we help landlords and property investors with all aspects of property tax, including capital allowances. Our team can review your expenditure and advise on the best approach for your portfolio. Explore our services to see how we can help, or contact us for a consultation.
For more guidance on landlord tax deductions, see our complete list of landlord tax deductions for 2025/26. If you are considering incorporating your property business, read our guide to buy-to-let limited companies.
Frequently Asked Questions
Sources
- gov.uk: Claim capital allowances: Annual investment allowance - GOV.UK
- icaew.com: Winners and losers from capital allowances changes - ICAEW.com
- taxscape.deloitte.com: writing-down allowances rate reduction and new first-year allowance
- globaltaxnews.ey.com: UK introduces Budget 2025 - Global Tax News Update - EY