A well-installed air source heat pump lasts 15–20 years, and the compressor is what usually decides the end of life. Circulation pumps, expansion vessels and sensors are 8–12 year consumables; a well-maintained enamelled cylinder lasts 15–25 years and a buffer tank longer still. Compressor wear is driven by the number of starts, not by running hours.
How long does an air source heat pump last?
Fifteen to twenty years for the unit as a whole, with the compressor as the limiting component — the same envelope quoted by manufacturers and confirmed by field studies of modern inverter equipment. That is longer than a typical gas boiler at 10–15 years, and shorter than the passive parts of the system around it. A heat pump installation is not one lifespan but several.
| Component | Typical service life | Usual failure mode |
|---|---|---|
| Compressor | 15 – 20 years | Cycling fatigue, oil migration, liquid return |
| Outdoor coil and casing | 15 – 25 years | Corrosion, worst within 1 km of the coast |
| Circulation pump | 8 – 12 years | Bearing wear, seized rotor after long shutdowns |
| Expansion vessel | 8 – 12 years | Diaphragm perishes, loses pre-charge |
| Sensors and control board | 10 – 15 years | Sensor drift, electronics failure |
| Enamelled DHW cylinder | 15 – 25 years | Corrosion once the anode is exhausted |
| Buffer tank | 20 – 30 years | Rarely fails — non-potable, low oxygen water |
The pattern is that anything touching potable water or moving continuously wears out first, and anything holding static heating water lasts almost indefinitely. Well-maintained solar collectors routinely run for 25 years or more for the same reason — no compressor, no consumables.
What actually kills a heat pump early?
- Short cycling. Every start draws high inrush current and momentarily starves the compressor of oil. A unit doing six starts an hour accumulates more damage in a season than one running steadily for years. See why does my heat pump keep switching on and off?
- Oversizing. An oversized unit cannot modulate down to a mild-day load, so it cycles by design. This is the single most common installation error and it is not repairable after the fact.
- Poor water quality. Sludge, no inhibitor and no dirt separator throttle flow, raise the temperature difference across the condenser and trip high-pressure cut-outs.
- Restricted airflow. Leaves, snow, a decorative enclosure or a hedge grown into the discharge path force longer, hotter running and more defrost cycles.
- Coastal corrosion. Salt attacks the fin stock. Coated coils and annual rinsing add years in exposed locations.
Do heat pumps last as long as gas boilers?
Longer, on the evidence. Gas boilers are generally replaced at 10–15 years, air source heat pumps at 15–20, and ground source units at 20–25 with a buried array rated for 50 years or more. The difference in practice is that a heat pump's life depends far more on how it was designed and commissioned than on which brand it is, whereas boiler life is fairly uniform.
How do refrigerant rules affect a heat pump's life?
They are worth factoring in for a system expected to run 15–20 years. The EU F-Gas Regulation cuts the HFC quota to 42.9 Mt CO₂e for 2025–2026 and cuts it to 17.1 Mt CO₂e for 2027–2029, so servicing gases get progressively more expensive even where they remain legal. The GWP 2,500 servicing ban that extends to air conditioning and heat pumps in 2026 does not catch R410A, but the quota squeeze does. Units built on R290 propane, with a GWP near zero, sit outside the phase-down entirely — a genuine consideration when a 2026 purchase is expected to run into the 2040s. The timeline is set out in the EU F-Gas Regulation and the R290 shift.
The maintenance that actually extends life is covered in do heat pumps need annual servicing?
Frequently asked questions
What is the average lifespan of an air source heat pump?
Fifteen to twenty years for a well-installed modern inverter unit, with the compressor as the limiting component. Poorly sized systems that short-cycle can fail much earlier, while units on steady low-temperature duty regularly exceed twenty years.
What part of a heat pump fails first?
In terms of end of life, the compressor. In terms of frequency, the circulation pump and the expansion vessel, both of which are 8–12 year consumables costing a small fraction of the machine and are routinely replaced without touching the refrigerant circuit.
Does running a heat pump constantly wear it out faster?
No — the opposite. Compressor wear tracks the number of starts far more closely than running hours. A unit running steadily at a low flow temperature lasts longer than one making the same heat in short bursts.
How long does the hot water cylinder last?
An enamelled cylinder typically lasts 15–25 years provided the magnesium anode is inspected every two years and replaced when consumed. Once the anode is gone, corrosion of the steel begins and the remaining life is measured in a few years.