The short answer
A well-installed, regularly serviced wall-mounted system typically lasts around 10 to 15 years, and some keep going longer. How long yours lasts depends on installation quality, how hard it works, where the outdoor unit sits and how it's looked after.
On this page
Air conditioning doesn't have a fixed expiry date. A system often doesn't fail all at once: it needs more repairs, loses some performance and eventually reaches the point where fixing it no longer makes sense. The figures here are typical expectations, not guarantees.
What wears out
| Part | What happens with age |
|---|---|
| Compressor | Wears and can fail; usually the most expensive part to replace |
| Fan motors | Bearings wear and get noisy |
| Circuit boards and sensors | Can fail with age, heat or electrical faults |
| Condensate pump, if fitted | Can need replacing well before the rest |
| Outdoor coil | Corrodes, especially near the sea |
| Outdoor pipe insulation | Breaks down in sunlight and weather |
| Brackets and casing | Metal can rust, and plastic fades and turns brittle |
Many of these parts can be replaced on their own, so one failure doesn't have to mean a new system. On an older system, a failed compressor is often what tips the balance towards replacement.
What shortens a system's life
- Poor installation. Badly made joints and pipework that wasn't properly pressure tested can leak. Moisture or air left in the refrigerant circuit because it wasn't properly evacuated does damage over time, and the wrong amount of refrigerant strains the compressor.
- The wrong size. An oversized unit tends to switch on and off more often, and an undersized one runs flat out for long periods. Both add wear.
- Neglect. Dirty filters, a clogged coil and a blocked outdoor unit make the system work harder and run hotter.
- A harsh site. Salt air near the coast, and dusty or polluted locations, corrode coils faster. Some outdoor units have coated coils intended for these sites.
- Heavy use. A system that heats all winter and cools all summer clocks up far more running hours than one used on a few hot days.
What helps it last
- Clean the filters every few weeks while the system is in regular use.
- Have it serviced regularly. Manufacturers typically recommend a service, often once a year, and what a service involves explains what's covered.
- Keep the outdoor unit clear of plants, leaves, snow and stored items.
- Get small problems, such as drips, new noises or ice, looked at early, before they strain other parts.
- Keep the installation, commissioning and service records together.
Manufacturer warranties vary in length and in what they cover, and some depend on regular servicing or on registering the product. Check the terms of yours so you don't lose cover by accident.
Repair or replace
When an older system develops a serious fault, these are the things to weigh up.
- Age and history. A major fault in a system near the end of its expected life, or in one that has needed several repairs, often points to replacement. A younger system is usually repaired.
- Refrigerant. R22 is an ozone-depleting refrigerant that has not been allowed for servicing equipment since 2015, so a refrigerant fault in an R22 system usually means replacing it. R410A has a high global warming potential (2,088), and rules on high-GWP refrigerants are tightening as the industry moves to lower-GWP options such as R32 (675). Older refrigerants: R22 and R410A explains more.
- Parts. Manufacturers eventually stop supplying parts for older models, and how long they remain available varies.
- Efficiency. Newer systems may have higher seasonal efficiency ratings. Compare the SEER and SCOP figures on the energy labels, as explained in energy labels: SEER and SCOP.
- Your needs. If the way you use the room has changed, a replacement can be sized and placed for how you use it now.
When a system is replaced
The refrigerant in the old system must be recovered by a qualified engineer and never released. The old units then go for proper disposal, as described in removing and disposing of an old system.
Whether the existing pipework can be reused depends on its size, its condition and the refrigerant it carried, and an installer will check. Depending on the model, the new outdoor unit may also need a different position, new brackets or changes to the electrical supply.
Related guides
- What a service involvesA service is a clean and check of the whole system, indoors and out, plus tests of how it runs and a look for leaks and wear. Manufacturers typically recommend one regularly, often once a year.
- Older refrigerants: R22 and R410AR22 damages the ozone layer and can no longer be used to service equipment, so a leaking R22 system usually means replacement. R410A is still widely used and can be serviced, but its high global warming potential means most new systems use R32.
- Removing and disposing of an old systemAn old split system has to be taken out by a qualified engineer, who recovers the refrigerant before anything is disconnected. The units then go for recycling as electrical waste, and the holes and fixings left behind need making good.
- Energy labels: SEER and SCOP explainedSEER and SCOP are the seasonal efficiency ratings on an air conditioner's energy label, for cooling and heating. Each shows roughly how much heat the unit moves over a standard season for every unit of electricity it uses, and higher is better.