Combi Boiler Replacement Cost 2026 (UK)
Replacing a combi boiler costs £1,800–£3,200 supplied and fitted in 2026 for a straight like-for-like swap in the same position. A larger or premium model, a change of location, or upgrading from an old back boiler or conventional system pushes the price higher. A combi is the UK's most popular boiler because it gives instant hot water with no cylinder or tank. Here is what a replacement costs in 2026, when to swap like-for-like versus upgrade, and how to cut the bill.
2026 combi boiler replacement costs
| Job | Typical price (2026) | Time |
|---|---|---|
| Like-for-like combi swap (budget model) | £1,800–£2,300 | 1 day |
| Like-for-like combi swap (mid/premium) | £2,300–£3,200 | 1 day |
| Combi swap with relocation | £2,600–£4,000 | 1–2 days |
| Convert system/regular to combi | £3,000–£4,500 | 1–2 days |
| Add filter & power flush | +£400–£700 | +0.5 day |
Like-for-like or upgrade?
If your current combi is well-sized and well-placed, a like-for-like swap is quickest and cheapest — the engineer reuses the existing pipework, flue and fixings. Upgrading to a higher flow-rate model makes sense if your showers feel weak, while converting from a system or regular boiler to a combi removes the cylinder and tanks but costs more because of the pipework changes and system flush.
How to cut the cost
- Get three quotes: boiler prices and labour vary widely — comparing is the single biggest saving.
- Keep the location: staying in the same spot avoids flue and pipework charges.
- Right-size, don't over-size: a correctly sized combi is cheaper to buy and run.
- Ask about fixed-price packages: many installers bundle boiler, flush and filter with a long warranty.
When is it worth replacing?
If your combi is over 10 years old, repeatedly breaking down, or losing efficiency, replacement usually pays back through lower bills and a fresh 7–12 year warranty. A newer boiler with a one-off fault is almost always cheaper to repair than replace.
FAQs
Related guides
- System boiler installation
- What size boiler do I need?
- Cost of moving a boiler
- Is it worth it? Insights
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