How long does a gas boiler last?
Typical
12 years
Range
10–15 years
A modern condensing gas boiler (including combis) typically lasts 10–15 years. The single biggest factor is annual servicing — most manufacturer warranties require it — and the state of the system water: sludge and scale quietly destroy heat exchangers.
What decides it
- Annual service — required by most warranties, and the main life-extender
- System water quality: inhibitor, a magnetic filter and a power flush when needed
- Hard-water scale on the heat exchanger in unsoftened areas
- Correct sizing — an oversized boiler short-cycles and wears faster
When to replace rather than repair
From around year 12, repairs involving the heat exchanger or main PCB usually cost enough that a new boiler (with a fresh 7–10 year warranty and better efficiency) wins.
Typical ranges from manufacturer guidance and industry surveys — individual machines vary with use and care. General information, not advice on a specific appliance.