Repair or replace your boiler?
A breakdown always seems to come in the cold snap, and the engineer's question is the same: pay to fix this one, or put the money toward a new boiler? It usually comes down to the boiler's age and how serious the fault is. Tell us the type, roughly how old it is and what's gone wrong, and we'll show you both costs side by side with a plain verdict. Free, no sign-up.
A guide, not a quote. The ranges are typical 2025/26 UK prices, inclusive of VAT, drawn from published industry averages: a repair is the call-out, parts and labour for the fault you've described; a replacement is a new boiler of the same type supplied and fitted in a like-for-like swap. They exclude a full system upgrade, moving the boiler, a power flush, new radiators or upgrading the flue, and assume a Gas Safe registered engineer. The only real number is a written quote — get at least two or three, and never let a boiler be condemned without a second opinion. Nothing you type leaves your browser.
It's mostly about age — and whether the fault is the expensive kind.
The 10–15 year rule. Most modern condensing boilers last 10 to 15 years. Under about 8 years and a fault is usually worth fixing — the boiler has plenty of life left and a repair is a fraction of replacement. Past 12–15 years, a major repair is throwing good money after bad: the next part is rarely far behind, efficiency has dropped, and the warranty is long gone.
Minor vs major faults. A pump, a thermostat, a diverter valve or a small leak is a routine, affordable fix at any age. The costly faults are the printed circuit board (PCB), the fan, the gas valve and especially the heat exchanger — on an older boiler one of those can be half the price of a new one, which is the classic tipping point.
The 50% guide. A common rule of thumb: if the repair costs more than about half the price of a new boiler, replacing is usually the better spend — you reset the clock, get a 5–10 year warranty and a more efficient unit that trims your gas bill. Repeated breakdowns or "parts no longer available" tip it further toward replacement even when a single repair looks cheap.
Efficiency pays you back. An old non-condensing or early condensing boiler can run at 70–80% efficiency; a new A-rated one is 90%+. On a typical home that can be £200–£300 a year off the gas bill, which closes part of the replacement cost over the boiler's life — and a smart thermostat or TRVs add a little more.
Get a second opinion before condemning. If an engineer says your boiler is dangerous and must be replaced, that may well be right — but a "condemned" boiler is also a big sale, so get a second Gas Safe engineer to confirm before you commit. Get two or three written quotes for the replacement, and check whether a power flush, flue work or a filter is included.
Keep your heating record in one place.
Stead tracks your boiler's age, service dates and warranty expiry, reminds you before the annual gas-safety service is due, and logs what a repair or replacement actually cost — so next time the question comes up you've got the history to answer it.