Ductless Mini-Split: Repair or Replace? (2026 cost comparison)
The rule of thumb, from Consumer Reports: don't spend more than 50% of a comparable new unit on fixing the old one. For a ductless mini-split, that 50% line is about £675–£2,250 — a new unit runs £1,350–£4,500 and typically lasts 10–20 years. If a repair quote lands under that line and the ductless mini-split is not yet past its expected life, repair usually wins. Reviewed July 2026.
Repair vs. replace, side by side Estimated
| Cost | Estimated range |
|---|---|
| Typical repair (this ductless mini-split, all faults we price) | £80–£1,600 |
| New ductless mini-split (unit only) | £1,350–£4,500 |
| The 50% line half a comparable new unit | £675–£2,250 |
Repair: min–max of every ductless mini-split fault we price (sources on each linked problem page) · New unit: Micro-Climate, WarmZilla · Lifespan 10–20 years: ACS Installations, Mechcool · 50% rule: Better Call Wes · Reviewed July 2026 · Estimated
Age × repair-cost worksheet Estimated
Find your ductless mini-split's age down the side and your repair quote across the top. The cell is the way the 50% rule points — Estimated guidance, not advice.
| Age of unit | Repair < 30% of a new ductless mini-splitunder £405–£1,350 | Repair 30–50%£405–£1,350 – £675–£2,250 | Repair > 50%over £675–£2,250 |
|---|---|---|---|
| Under 8 years first half of typical life | Repair likely | Repair likely | Compare quotes |
| 8–20 years second half, under typical lifespan | Repair likely | Compare quotes | Replace likely |
| Over 20 years at or beyond typical lifespan | Compare quotes | Replace likely | Replace likely |
How this is built: we apply the 50% rule (Better Call Wes) — spend no more than half a comparable new unit's cost on a repair — with its lifespan corollary (replacement is favored once the unit is past the midpoint of its expected life and the quote tops 50%). Columns are your repair quote as a share of a new ductless mini-split (£1,350–£4,500); the £675–£2,250 and £405–£1,350 thresholds are just 50% and 30% of that range. Rows use the midpoint of the expected life (about 8 years — halfway through a typical 15-year lifespan) and the top of the sourced 10–20 years range (20 years). Nothing here is a per-unit price or a recommendation — it is a transparent reading of the rule.
The wall-mounted split (and multi-split) is what 'domestic air conditioning' means in the UK — ducted whole-home cooling is not the default here the way it is in the US, so the UK central-ac type folds into THIS type (see types.central-ac, whose lifespan is null). The 10-20 range is deliberately the union of two UK sources that genuinely disagree (Mechcool 10-15, ACS 15-20) rather than a narrowed midpoint neither source states. Note that ACS states 15-20 for a pooled 'split/central' class and does not separate the two, so it cannot on its own distinguish a UK split from a UK ducted-central unit. Any repair touching the refrigerant circuit is subject to the F-Gas qualification requirement in the heuristics above, which materially limits who may legally carry out a recharge or leak repair. No US mini-split lifespan has been carried over. The new_unit_gbp range GBP 1,350-4,500 is the bundled supplied-and-fitted price of a wall-mounted split, bracketed from two independent UK sources fetched live 2026-07-22 (Micro-Climate's per-room supply-and-fit floor, WarmZilla's single-split installed ceiling). UK sources genuinely disagree on the floor: a third source, MyJobQuote (https://www.myjobquote.co.uk/costs/installing-air-conditioning, fetched 2026-07-22: GBP 550-2,100 for a single split, about GBP 1,200 average, plus GBP 600-1,200 per additional room), sits lower and is recorded here rather than averaged in — its GBP 550 low outlier is deliberately excluded from the carried floor. Multi-split systems and whole-home ducted air conditioning run above this single-split band. install_delivery_gbp is null on the bundled-total convention, matching the US file.
One more thing before you replace
A newer ductless mini-split can cut energy and water use, which shifts the math on an older unit even when a repair is cheap: ENERGY STAR notes clothes washers over ~10 years and refrigerators over ~15 years are common efficiency-driven replacements.
Energy note: · Reviewed July 2026 · Estimated · Informational only
Price the repair first
Before you decide, get the likely repair figure for the exact fault — each page localizes to your metro:
- Full ductless mini-split cost guide
- Not cooling
- Not heating
- Refrigerant leak repair / recharge
- Compressor replacement
- Indoor blower / fan motor replacement
- Indoor head leaking water
- Error code / flashing light fault
- Control board / PCB replacement
- Outdoor unit not running
- Musty or mouldy smell from the indoor unit
Estimated ranges — see the methodology for how we build the repair figures and their named sources. This page is informational and is not repair, purchasing, or financial advice.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).