Guide
Should you repair or replace your boiler?
How age, the fault, parts, efficiency and safety decide whether a boiler is worth repairing, and what to weigh up before replacing.
Updated
When repair usually makes sense
A boiler under about ten years old, with a common, reasonably priced fault, that has been serviced and otherwise reliable, is usually worth repairing. So is any boiler still under its manufacturer’s warranty, where the repair may cost nothing at all.
When replacement starts to make sense
Age is the first sign: beyond about twelve to fifteen years, parts get harder to find and failures come closer together. A failed main heat exchanger, a major part costing a large share of a new boiler, or a part that is no longer made all point towards replacement. So does a third breakdown in a single winter.
Efficiency is the second. A non-condensing boiler from before the mid-2000s wastes a meaningful share of its fuel compared with a modern condensing one, and on oil or LPG, where fuel is expensive, that difference adds up quickly.
Safety is the third. If an engineer labels your boiler "at risk" or "immediately dangerous" under the gas industry unsafe situations procedure, take it seriously. They are required to tell you, and they will not leave a dangerous appliance running.
Before you replace
Get at least two written quotes, and compare what they include: the boiler model and warranty, the system clean, magnetic filter, inhibitor, controls and, in a hard water area, a scale reducer. Check the installer is Gas Safe registered for gas or OFTEC registered for oil, and that the installation will be registered with building control.
Off the gas grid, consider whether a heat pump suits the house before ordering another oil boiler, and check whether a government grant is available at the time.