Should I repair or replace my boiler?
A straight framework for deciding, without the sales pitch. Sometimes the repair is obviously right, and we will say so.
14 July 2026 · 6 min read
Every comparison site has an incentive to tell you to replace. We get paid when you ask for quotes. So take this in that spirit, and note that we are about to tell you when NOT to.
Repair it if
The boiler is under eight years old. Modern boilers are built to last twelve to fifteen with servicing, and a fault at year six is bad luck, not old age.
It is still in warranty. Obviously. Ring the manufacturer before anyone else.
The fault is a known consumable: a diverter valve, an expansion vessel, a pump, a PCB on an otherwise healthy unit. These are the parts that go, and replacing one on a young boiler is normal maintenance, not throwing good money after bad.
Replace it if
It is over twelve and the repair is more than about £400. You would be spending real money on a machine with limited road left, and you get no warranty for it.
It has broken down twice or more in two years. Boilers rarely fail once. The second failure is the system telling you something.
Parts are getting hard to find. If your engineer says 'I can get one, but it will take a week', imagine that week being in January.
It is a G-rated non-condensing unit. These waste up to a third of the fuel you buy. The Energy Saving Trust puts the annual saving from replacing one at up to £840 for a detached home - which is not a quote, it is a market figure, and your number depends on your house and your tariff.
The maths people get wrong
A £400 repair on a fifteen-year-old boiler is not £400. It is £400, plus the gas you keep wasting, plus the odds of the next repair, plus the chance it goes on the coldest weekend of the year when the call-out rate doubles.
A £2,500 replacement is not £2,500 either. It is £2,500 minus the fuel you stop wasting, minus the repairs you no longer pay for, plus ten years of warranty. Over a decade the gap narrows a lot.
What to do next
Get the fault diagnosed and get a repair price. Then get two or three replacement quotes so you can compare like with like. If the repair is clearly the better call, take it - nobody is forcing your hand.