Is a New Boiler Tax Deductible for Landlords?
Like-for-like replacement is an allowable repair; first-time heating or a heat-pump upgrade is capital. The HMRC test, a worked example and where it goes on your return.
The short answer
Usually yes — as a repair. Replacing a worn or broken boiler with a modern equivalent restores the property rather than improving it, so the full cost is deductible from rental income in the year you pay it. It becomes capital (relieved against CGT on sale, not income) only when you install heating that was never there or make a genuine upgrade.
“Is a new boiler tax deductible?” is the most-asked repair question landlords have — and the answer turns entirely on HMRC’s repair-versus-improvement test, not on how much it cost or how new the boiler is.
Why a like-for-like swap is a repair
HMRC’s own manual says replacing a worn part with the nearest modern equivalent is a repair even when the new item is better, because the old spec is no longer sold. A condensing combi replacing a failed combi is the textbook allowable repair — the property is back to the standard it had before, using today’s technology. The efficiency gain is incidental, not the purpose.
When a boiler becomes capital
The cost tips into capital when the work creates something better than existed: first-ever central heating, a system materially larger than the old one, or a boiler replaced as part of a wider refurbishment that changes the property’s character. Capital costs are not lost — they add to your base cost for Capital Gains Tax when you sell — but they do nothing for this year’s rental profit.
| Scenario | Likely treatment |
|---|---|
| Broken combi replaced with a similar combi | Revenue repair — deduct in full |
| Old non-condensing boiler replaced with condensing model (only type now sold) | Revenue repair |
| Gas boiler replaced with a heat pump under an upgrade programme | Likely capital (improvement) — take advice |
| Central heating installed where there was none | Capital — CGT base cost |
| Boiler replaced during a full strip-out refurbishment before first letting | Usually capital (see pre-letting rules) |
Worked example
A landlord pays £2,800 to replace a failed boiler in June 2026. Treated as a repair, it reduces rental profit by £2,800:
| Deducting £2,800 in 2026/27 | Effect |
|---|---|
| Basic-rate landlord (20%) | £560 less tax |
| Higher-rate landlord (40%) | £1,120 less tax |
| Additional-rate (45%) | £1,260 less tax |
| From April 2027 (property rates 22/42/47%) | slightly more — the deduction is worth more as rates rise |
The same £2,800 treated as capital saves nothing this year and reduces a future gain by at most £672 (24% CGT rate). Getting the classification right is worth real money — which is exactly why HMRC looks at it.
The heat-pump question
Swapping a gas boiler for an air-source heat pump is not a like-for-like replacement; it is a different system and normally an improvement. Boiler Upgrade Scheme grants reduce the cost you can claim either way. We could not find HMRC guidance that treats a heat pump as a repair — treat it as capital unless your adviser argues otherwise on your facts.
What to keep
The invoice describing the work, proof of payment, and — for anything near the repair/improvement line — a sentence in your records saying what was there before. HMRC enquiries into landlord expenses turn on that single fact. Digital copies satisfy MTD’s record-keeping rules.
Where it goes under Making Tax Digital
If you are inside MTD for Income Tax (mandated from April 2026 above £50,000 gross), the cost belongs in your quarterly update under the matching expense category, in the quarter you paid it (cash basis is the default for landlords). Get the category right now — the final declaration only tidies totals, it does not re-classify. Check whether MTD applies to you.
HMRC Property Income Manual PIM2020 (repairs and renewals — like-for-like modern equivalent is a repair) · gov.uk “Work out your rental income when you let property” · rates from our verified 2026/27 dataset. Checked 31 Aug 2026.
Quick answers
A like-for-like replacement of a failed or worn boiler — including upgrading to a condensing model because that is all that is sold — is a repair, deductible against rental income. Installing heating that did not exist, or a materially bigger or different system, is a capital improvement.
Repairs before first letting are allowable only if the property was already in a lettable state and the cost is genuinely a repair. A boiler replaced as part of making a run-down purchase fit to let is normally capital. Ordinary servicing and small fixes in the pre-letting period are usually fine.
Not like-for-like. A heat pump is a different heating system and is normally treated as an improvement (capital). Grant funding reduces the claimable cost in either case.
As a repair it goes in the repairs and maintenance box of the SA105 property pages (Box 25), or the repairs category of your MTD quarterly update. As capital it goes nowhere on the income side — keep the invoice for your CGT calculation.