The honest answer
Most gas boilers give reliable service for 10 to 15 years. Past that, efficiency drops, parts get harder to source and the cost of keeping it going starts to outweigh the cost of replacing it.
Five signs worth acting on
- Repeat breakdowns. Two or more faults in a single heating season usually means the next one is not far away.
- Rising gas bills with no change in how you heat the house.
- Cold spots and slow warm-up across radiators, often alongside noisy pipework.
- A yellow rather than blue flame, or any smell of gas — turn it off and call a Gas Safe engineer immediately.
- Parts no longer available for the model, which makes any future repair impossible.
What a replacement actually involves
We survey the property, check the gas supply and flue route, calculate the heat load and size the boiler to the house rather than simply matching what was there before. An oversized boiler cycles constantly and wastes gas.
Installation on a straight swap is typically one day, a system change two to three. You get the Gas Safe certificate, manufacturer warranty registration and a system flush as standard.
Before you commit
Get a written, itemised quote. It should name the boiler model, the controls, the flush method and the warranty length. If a quote does not include those, it is not a quote — it is a guess.