The expected lifespan
The most direct statement from a source this site relies on comes from the Energy Saving Trust, in its answers to common heat pump questions (27 May 2026): once the system is installed correctly, the heat pump itself is likely to last 20 years or more, which it says is longer than the average gas or oil boiler. That is an expert expectation. It is not a warranty, and nobody has yet watched a large population of modern UK domestic heat pumps for two decades, so treat it as a planning assumption and check it against the manufacturer’s warranty.
Note what the statement covers: the heat pump itself. Other parts of the system age on their own schedules. The hot water cylinder, circulation pumps, valves, controls and any radiators or pipework you added are separate items, and a ground source system has a buried ground loop as well. Ask the installer for the expected life and warranty of each major component rather than one headline figure.
What affects how long it lasts
The Energy Saving Trust says that historically UK homes saw problems from poor installations, including systems not sized correctly, radiators not upgraded, narrow-bore pipework not replaced and pipework not insulated, and that as standards have tightened, equipment improved and supply chains matured, these are much less common. It adds that once the system is installed correctly, you are not likely to see much equipment failure, and that performance issues mostly come from how the system is set up and used.
| Factor | Why it matters |
|---|---|
| Design and sizing | A heat pump sized from a proper heat-loss calculation is not forced to work against the house. See sizing and radiators. |
| Installation quality | Pipework replaced and insulated where needed, system flushed, commissioning done properly. |
| Heating water quality | The Trust says no water treatment or filter can cause long-term problems that may be expensive to fix; sludge and dirt can also mimic a heat pump fault. |
| How you run it | The Trust says treating it like a gas boiler leads to higher bills, poor comfort and a greater risk of equipment failure. |
| Servicing and fault handling | Yearly service and prompt action on fault messages reduce the risk of a breakdown in winter. |
| Siting of the outdoor unit | Clear airflow helps efficiency; keep bikes, bins and leaves away. |
Upkeep that protects it
The Trust recommends a service according to the manufacturer’s advice, usually once a year, at a typical cost it puts at around £150. Beyond the service, it advises you to learn the controls, check the fault log for recurring messages and talk to the installer and manufacturer about them. The service and maintenance guide lists what a service covers, and the controls guide explains the settings worth understanding.
If something does go wrong early, the route depends on who is at fault. A faulty product points to the manufacturer; workmanship points to the installer and their consumer code. The complaints guide sets out the escalation.
What it means for value
A long life changes how you read the price. The 2026 Q3 official median for an installed air source heat pump was £12,826 including the grant value (DESNZ, 29 October 2026), or around £5,326 after a £7,500 grant. Spread over a 20-year life, that is a smaller annual cost than the headline suggests, but that arithmetic only works if the system performs for the full period, and savings on bills depend on your fuel and tariff. Put it next to your current boiler’s expected replacement cost, and use the worth-it guide to test the running side.
What to ask before you buy
- What is the manufacturer’s warranty on the heat pump, and what does it cover?
- What does your workmanship warranty cover, and for how long?
- Is an annual service required to keep the warranty, and what does it cost?
- Will you treat the heating circuit (flush, filter, inhibitor) and say so on the quote?
- Who deals with a fault, and how quickly?
Put the answers in writing and compare them on the quotes checklist. The warranty guide goes into the paperwork, and the installer guide shows how to build a shortlist.