New Oil Boiler Costs: A 2026 Price Guide
Investing in a New Oil Boiler
Is your old boiler making strange noises, breaking down frequently, or just costing a fortune to run? It might be time to replace it.
While a new boiler is a significant expense, modern condensing oil boilers are over 90% efficient, compared to 60-70% for older models. The fuel savings alone can often pay for the upgrade over time.
Average Installation Costs (2026)
The total cost depends heavily on whether you are doing a "straight swap" (replacing like-for-like) or changing the system type (e.g., moving from a regular boiler to a combi).
| Installation Type | Boiler Cost | Installation & Parts | Total Estimated Cost |
|---|---|---|---|
| Straight Swap (Regular) | £1,500 - £2,500 | £1,000 - £1,800 | £2,500 - £4,300 |
| Straight Swap (Combi) | £1,800 - £3,000 | £1,200 - £2,000 | £3,000 - £5,000 |
| System Change (Regular to Combi) | £1,800 - £3,000 | £2,000 - £3,500 | £3,800 - £6,500 |
Note: These are average UK prices. London and the South East may be higher.
Breakdown of Costs
1. The Boiler Itself (£1,500 - £3,000)
- Budget brands: (e.g., Warmflow) offer good value but may have shorter warranties.
- Premium brands: (e.g., Grant, Worcester Bosch) cost more but often come with 5-10 year warranties and better build quality.
2. Labour & Installation (£1,000 - £3,000)
- Draining the old system and removing the old boiler.
- Pipework modifications.
- Electrical connections.
- Commissioning and testing.
- System flushing: Essential to remove sludge so it doesn't damage the new boiler.
3. The "Hidden" Extras
- Magnetic Filter (£150): Highly recommended to protect your new boiler from sludge.
- Thermostatic Radiator Valves (TRVs): You might need to upgrade your radiator controls to meet building regulations.
- New Flue: If the new boiler is in a different position, you might need a new flue kit.
- Oil Line Upgrade: Older oil supply pipes might need upgrading to meet current environmental standards.
Regular vs Combi: Which is Best?
Regular (Heat Only) Boiler
- Best for: Large homes with multiple bathrooms where people might shower at the same time.
- Pros: Good water pressure, backup immersion heater if boiler breaks.
- Cons: Takes up space (hot water tank + cold water tank in loft).
Combi Boiler
- Best for: Smaller homes or those with 1-2 bathrooms.
- Pros: Instant hot water, no tanks needed (frees up space).
- Cons: Flow rate can drop if two taps are open at once; no backup hot water if boiler breaks.
Oil vs Heat Pump?
With the push for green energy, you might be considering a heat pump instead.
- Oil Boiler: £3k - £5k. Cheaper upfront, higher running costs (carbon intensive).
- Air Source Heat Pump: £10k - £16k. Expensive to install (though grants of £7.5k are available), lower/similar running costs, very low carbon.
The Verdict: If you have a well-insulated home and can afford the upfront contribution, a heat pump is future-proof. However, for many older, draughty rural homes, a modern high-efficiency oil boiler remains the most practical and cost-effective solution for now.
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