Your boiler has broken down and the engineer says it needs a £400 part. Do you pay for the repair or put the money towards a new boiler? Here's how to think through the decision.
The 50% rule
The most common rule of thumb in the industry: if the repair costs more than 50% of the cost of a new boiler, replacement is usually better value.
A new combi boiler starts from £999 fitted. So if a repair costs £500+, replacement is worth considering.
Other factors that favour replacement
- Age: A boiler over 12 years old is likely to have further failures even after a repair. You may be paying for a short-term fix.
- Efficiency: Old boilers (pre-2005) may be only 70–80% efficient. A new A-rated boiler at 92%+ can reduce gas bills by £200+/year — which quickly offsets the replacement cost.
- Repeat breakdowns: If you've had 2+ call-outs in the past year, the boiler is deteriorating and further repairs are likely.
- Parts availability: For older boilers, some parts may be discontinued or hard to source.
When repair genuinely makes sense
If the boiler is less than 8 years old, the repair is straightforward, and it's the first breakdown, repair is almost always the right call. Modern boilers are designed to be repaired, and a single repair on a young boiler is entirely normal.
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