Repair or Replace Your Air Conditioning?
A repair quote in one hand, a sense that the unit is getting old in the other. The thresholds engineers actually use — age, refrigerant, the 50% rule, efficiency and warranty — a decision table, and a route to quotes for either outcome.
The 10–15 year threshold
A domestic split system installed well and serviced annually typically lasts 10–15 years. Past ten, three things change at once: components such as fan motors, PCBs and compressors reach the end of their design life, manufacturers begin to run down spare parts for the range, and the efficiency gap against a current unit becomes large enough to notice on a bill. A single cheap fault on a twelve-year-old unit is still worth fixing; a second significant one in the same year usually is not.
Find the age from the outdoor unit's data plate (serial numbers usually encode the year) or the installer's paperwork. If you cannot find out, assume it is older than it looks.
R22, R410A and R32 — why the gas decides more than you would think
R22: an ozone-depleting HCFC, banned for servicing and top-up since 2015. A unit on R22 that develops any refrigerant-side fault cannot legally be re-gassed; it is replacement by default. If your outdoor unit plate says R22, plan now rather than in a heatwave.
R410A: the standard of the 2000s and 2010s, a high-GWP HFC now being phased down under the F-Gas quota regime. Still legal to service, but each year the quota shrinks and the gas gets dearer. A leak repair and re-gas — £100–£300 today — is a recurring exposure on an old R410A unit, and the gap to a new system narrows every time.
R32: the current standard for new splits, lower GWP, more efficient per kilogram of charge, and what every vetted, F-Gas certified installer fits today. New units from Daikin, Mitsubishi Electric, Fujitsu, Panasonic, LG and Samsung are R32 as standard.
Repair cost versus a new system
The rule of thumb engineers use: if the repair quote exceeds half the cost of an equivalent new system, replace. For a typical single wall-mounted split (2.5–3.5 kW) supplied and installed at £1,500–£3,000 — most commonly £1,800–£2,500 — the tipping point is roughly £750–£1,500. Multi-splits scale: two rooms £2,800–£5,000, three rooms £4,500–£7,500.
Apply it with age in mind: a £300 repair on a five-year-old unit is obvious; the same £300 on a fourteen-year-old R410A unit that has already had a fan motor is not, because the next fault is coming. A compressor quote on a three-year-old unit goes back to the installer under warranty, not to this table.
Cheap, confident repairs: filters, capacitors, fan motors, condensate pumps, sensors, drain faults — see repair costs. Expensive, replace-leaning repairs: compressor, inverter PCB on an older unit, repeated leaks, anything on R22.
What a new unit buys you beyond "it works again"
Running costs. Modern inverter units modulate rather than switch on and off, and carry SCOP ratings of 3.5–4+ for heating alongside strong cooling efficiency. At around 26p/kWh (July 2026 cap, typical dual-fuel bill £1,663 a year) a 2.5 kW unit draws roughly 0.7–0.9 kW and costs about 18–23p an hour; an old non-inverter unit delivering the same comfort draws more. Bear in mind air-to-air heat pumps are not eligible for the Boiler Upgrade Scheme grant, so there is no subsidy to factor in — the case rests on the bill and the repair quote.
Warranty. Premium brands such as Daikin and Mitsubishi Electric offer 5–7 year warranties when installed by accredited installers; mid-range Fujitsu, Panasonic, Toshiba and Hitachi and value LG and Samsung also carry manufacturer cover. A repaired old unit has whatever guarantee the engineer gives on the part — typically months, not years.
Lean repair or lean replace?
| Situation | Lean repair | Lean replace |
|---|---|---|
| Unit under 7 years, single fault | Yes — and check warranty first | Only if compressor out of warranty |
| Unit 7–10 years, modest fault (fan, capacitor, pump, sensor) | Yes | No |
| Unit 10–15 years, modest fault | Usually — first time | Second significant fault in 12 months |
| Unit 10–15 years, compressor or inverter PCB | Rarely | Yes |
| Any age on R22 | Electrical/mechanical only | Any refrigerant-side fault |
| R410A with a leak | If under 10 years and single leak | Repeated leaks or over 10 years |
| Repair quote over half the new-system price | No | Yes |
New-system baselines: single split £1,500–£3,000 (typical £1,800–£2,500); 2-room multi £2,800–£5,000; 3-room £4,500–£7,500. Repair baselines: call-out £80–£150, re-gas £100–£300.
Sources & methodology
- Refrigerant rules: R22 service ban from 1 January 2015; HFC phase-down and quotas under the GB F-Gas Regulation (retained Regulation (EU) 517/2014); R32 as the current standard for new split systems.
- Running-cost inputs: electricity ~26p/kWh under the July 2026 Ofgem price cap (typical dual-fuel £1,663/yr); 2.5 kW cooling draws ~0.7–0.9 kW. Boiler Upgrade Scheme eligibility excludes air-to-air systems.
- Price baselines are 2026 UK figures used across this site; quotes vary by brand, capacity, access and pipework.
FAQs
Get quotes for the repair — and for the replacement
Not sure which way to go? Get both. We match you with vetted, F-Gas certified engineers for repair quotes, and with installers for a new-system price, so you can compare real numbers rather than rules of thumb. Free, no obligation.