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How long do heat pumps last? Lifespan, reliability and when to replace
Quick answer
Air source heat pumps typically last 15 to 20 years with regular servicing. Some last longer. The main factors are how well the system is maintained, the quality of the original installation, and how hard the system works. OVO's installations come with a 10 year workmanship warranty as standard.
Heat pumps are built to last. They have fewer moving parts than a gas boiler and no combustion components, which means there is less to go wrong over time. But like any mechanical system, they do not last forever. Knowing what affects lifespan and when to consider a replacement can save you money and prevent an unexpected breakdown.
How long do air source heat pumps last?
Most air source heat pumps have a lifespan of 15 to 20 years. This is broadly comparable to a gas boiler, which typically lasts 10 to 15 years with good maintenance. Some heat pumps last well beyond 20 years, particularly those that have been regularly serviced and correctly sized for the property from the start.
| Component: | Typical lifespan: | Notes: |
|---|---|---|
| Heat pump unit (compressor and outdoor unit) | 15 to 20 years | Main component, sets the overall lifespan |
| Inverter | 10 to 15 years | May need replacing mid life |
| Hot water cylinder | 20 to 25 years | Often outlasts the heat pump itself |
| Controls and thermostat | 10 to 15 years | Usually replaced as part of a system upgrade |
Lifespans are approximate and depend on usage, maintenance, and installation quality.
What affects how long a heat pump lasts?
Several factors determine whether your heat pump reaches the top end of its expected lifespan or falls short of it.
The most important factor. A heat pump that is incorrectly sized, poorly commissioned, or installed with inadequate pipework will work harder than it needs to and wear out faster. This is why choosing an MCS certified installer matters. OVO's installations are carried out by accredited local engineers and come with a 10 year workmanship warranty.
An annual service keeps all components running efficiently, catches minor issues before they become major ones, and maintains your manufacturer warranty. Heat pumps that are never serviced tend to develop faults earlier and cost more to run.
A heat pump that is too small for the property runs constantly to keep up with demand, which accelerates wear. A system designed correctly for heat loss runs at a comfortable, efficient pace.
Heat pumps in very cold or coastal locations work harder and may need more frequent servicing. Modern heat pumps are designed to operate effectively in UK winter temperatures, typically down to minus 15 to 20 degrees, so climate is rarely a major issue in the UK.
A heat pump running 24 hours a day in a large, poorly insulated property will wear faster than one in a well insulated home with lower demand.
How does heat pump lifespan compare to a gas boiler?
| Air source heat pump | Gas boiler | |
|---|---|---|
| Typical lifespan | 15 to 20 years | 10 to 15 years |
| Annual service required | Yes | Yes |
| Main component that fails | Compressor | Heat exchanger or pump |
| Replacement cost | £8,000 to £15,000 installed | £2,000 to £4,000 installed |
| Grant available | £7,500 BUS grant | None |
| Running cost trend | Stable, with long term potential as the grid decarbonises | Rising as gas prices increase |
Heat pumps generally last longer than gas boilers and the higher upfront replacement cost is offset by the BUS grant and lower long term running costs for most households. The higher upfront replacement cost is offset by the BUS grant and lower long term running costs for most households.
Signs it might be time to replace your heat pump
Most heat pumps give warning signs before they fail completely. Here are the main ones to watch for.
• The system is more than 15 years old and having recurring faults.
• Repair costs are becoming significant, typically more than 30 to 40% of a new unit's cost.
• The system can no longer maintain a comfortable temperature even on mild days.
• Energy bills have risen significantly without a change in usage or tariff.
• The refrigerant used in your system has been phased out and is no longer available or legal.
• A qualified engineer has advised that the compressor is failing.
A single fault does not necessarily mean replacement is needed. But a pattern of faults in an older system usually does.
Can a heat pump be repaired rather than replaced?
Often yes, especially for systems under 12 to 15 years old. Common repairs include replacing the fan motor, fixing refrigerant leaks, replacing the expansion valve, or updating the controls. These are typically far cheaper than a full replacement.
The decision comes down to age, repair cost, and efficiency. An older heat pump repaired back to working order may still be significantly less efficient than a modern equivalent. If your system predates modern inverter technology, a replacement may deliver better running costs even accounting for the upfront cost.
What happens to the hot water cylinder when you replace a heat pump?
In most cases the hot water cylinder can be kept if it is in good condition and compatible with the new heat pump. Cylinders typically outlast the heat pump itself. Your installer will assess the cylinder as part of the replacement survey.
Frequently asked questions
How long do air source heat pumps last in the UK?
Most air source heat pumps last 15 to 20 years in the UK with regular annual servicing. The UK climate is not particularly harsh for heat pumps and most modern units are designed to handle typical British winters without difficulty.
What is the most common reason a heat pump fails?
Compressor failure is the most common cause of a heat pump reaching end of life. The compressor is the heart of the system and the most expensive component to replace. Regular servicing helps identify early signs of compressor stress before it fails completely.
Is it worth repairing an old heat pump?
It depends on the age and the cost of the repair. As a rough guide, if the repair costs more than a third of what a new system would cost and the heat pump is over 12 years old, replacement is usually the better long term decision. Your engineer can advise on the specific situation.
Does the 10 year OVO warranty cover the full lifespan?
OVO's 10 year workmanship warranty covers the quality of the work carried out during installation. The heat pump unit also comes with a manufacturer's warranty, typically 5 to 7 years, which covers component defects. Neither warranty covers normal wear and tear or end of life replacement.
When is the best time to replace a heat pump?
Replacing before a complete failure gives you time to plan, get quotes, and apply for any available grants. The £7,500 Boiler Upgrade Scheme grant applies to replacement heat pumps as well as new installations, provided you are replacing a fossil fuel heating system. If you are replacing one heat pump with another, check current eligibility with your installer.
Get a free heat pump quote from OVO
Whether you are installing a heat pump for the first time or replacing an existing system, OVO's local engineers can survey your home and give you a fixed quote. The £7,500 Boiler Upgrade Scheme grant is available on qualifying installations and OVO handles the application on your behalf.