When your boiler starts making strange noises, taking ages to heat up, or breaking down every winter, the question stops being "should I replace it" and becomes "how much is this going to cost me."
This guide gives you honest numbers for new boiler costs in the UK in 2026, covering every type of boiler, installation scenarios, and what actually drives the price up or down.
A new combi boiler installed costs £2,000 to £3,500 for a straightforward swap. A system boiler runs £2,500 to £4,500. Converting from one boiler type to another or moving the boiler to a new location adds £500 to £1,500 to the bill.
Boiler Costs at a Glance
| Boiler Type | Supply Only | Installed |
|---|---|---|
| Combi boiler (like for like swap) | £800 to £2,000 | £2,000 to £3,500 |
| System boiler | £1,000 to £2,500 | £2,500 to £4,500 |
| Conventional (regular) boiler | £800 to £2,000 | £2,000 to £4,000 |
| Boiler conversion (e.g. regular to combi) | £1,000 to £2,500 | £3,500 to £5,500 |
| Boiler relocation (moving to new position) | Add £500 to £1,500 | |
Combi Boiler Costs in Detail
Combi boilers are the most popular choice in the UK, fitted in around 70% of homes. They heat water on demand and do not need a separate hot water cylinder or cold water tank in the loft, which saves space.
| Brand | Budget Model | Mid Range | Premium |
|---|---|---|---|
| Worcester Bosch | £1,000 to £1,400 | £1,400 to £1,800 | £1,800 to £2,500 |
| Vaillant | £900 to £1,300 | £1,300 to £1,700 | £1,700 to £2,200 |
| Ideal | £700 to £1,000 | £1,000 to £1,400 | £1,400 to £1,800 |
| Baxi | £700 to £1,000 | £1,000 to £1,300 | £1,300 to £1,700 |
These are supply only prices. Add £800 to £1,500 for installation depending on the complexity and your location.
Regional Price Variations
Boiler installation costs vary by region because labour rates differ significantly. The boiler unit itself costs the same wherever you buy it, but the installation labour is where regional differences show up.
| Region | Combi Swap (installed) | Conversion (installed) |
|---|---|---|
| London | £2,500 to £4,500 | £4,500 to £7,000 |
| South East | £2,200 to £4,000 | £4,000 to £6,500 |
| Midlands | £2,000 to £3,500 | £3,500 to £5,500 |
| North of England | £1,800 to £3,200 | £3,200 to £5,000 |
| Scotland | £1,900 to £3,300 | £3,300 to £5,200 |
| Wales | £1,800 to £3,000 | £3,000 to £5,000 |
The gap between London and the North can be £500 to £1,500 for the same job with the same boiler. If you live near a regional boundary, it can be worth getting quotes from engineers in both areas.
Budget vs Mid Range vs Premium Boilers
| Feature | Budget (£1,800 to £2,500) | Mid Range (£2,500 to £3,500) | Premium (£3,500+) |
|---|---|---|---|
| Brand | Baxi, Ideal | Vaillant, Ideal Vogue | Worcester Bosch, Viessmann |
| Warranty | 2 to 5 years | 5 to 10 years | 10 to 12 years |
| Efficiency | 89% to 92% | 92% to 94% | 94% to 98% |
| Hot water flow | 10 to 12 litres/min | 12 to 14 litres/min | 14 to 17 litres/min |
| Smart controls | Basic thermostat | Programmable thermostat | Smart thermostat, app control |
| Noise level | Audible | Quiet | Near silent |
Installation Costs Breakdown
| Installation Type | Labour Cost | Time |
|---|---|---|
| Like for like combi swap | £800 to £1,200 | 4 to 6 hours |
| Like for like system boiler swap | £1,000 to £1,500 | 6 to 8 hours |
| Regular to combi conversion | £1,500 to £2,500 | 1 to 2 days |
| Boiler relocation | £500 to £1,500 | Additional half to full day |
| Flue extension or re-route | £150 to £400 | Additional 1 to 2 hours |
| Magnetic filter installation | £100 to £200 | 30 minutes |
| Powerflush (system clean) | £300 to £600 | 4 to 8 hours |
A straightforward combi to combi swap in the same location is the cheapest installation. The engineer disconnects the old boiler, hangs the new one in the same spot, connects the pipework, and commissions it. Total time is usually half a day.
What Size Boiler Do You Need?
| Property Size | Radiators | Recommended Output |
|---|---|---|
| 1 bed flat | Up to 10 | 24 to 27 kW |
| 2 to 3 bed semi | 10 to 15 | 28 to 32 kW |
| 3 to 4 bed detached | 15 to 20 | 32 to 38 kW |
| 4+ bed large property | 20+ | 35 to 42 kW (or system boiler) |
Oversizing a boiler wastes energy and money. Undersizing means not enough hot water when you need it. A good Gas Safe engineer will do a proper heat loss calculation rather than just guessing. If anyone suggests a boiler size without counting your radiators and checking your hot water demand, find someone else. The calculation should account for your property size, insulation levels, window types, and hot water usage patterns. Larger properties with multiple bathrooms may need a system boiler rather than a combi, because combis struggle to supply more than one hot water outlet at the same time.
Running Costs: How Much Does It Cost to Run a Boiler?
The purchase price is only part of the equation. A new boiler should reduce your energy bills compared to an older, less efficient model. Modern condensing boilers run at 90% to 98% efficiency, meaning almost all the gas you pay for is converted into heat. An older non condensing boiler operates at 60% to 80% efficiency, wasting 20% to 40% of the gas you pay for.
For a typical three bedroom house, annual gas costs for heating and hot water are roughly £800 to £1,200 per year. Upgrading from an old G rated boiler to a new A rated model can save £200 to £400 per year on gas bills. Over the 10 to 15 year lifespan of the boiler, that is £2,000 to £6,000 in savings, which partially or fully offsets the cost of the new boiler.
A smart thermostat (£150 to £250 installed) can add further savings of 10% to 15% on heating bills by learning your schedule and avoiding heating an empty house. Many boiler manufacturers offer smart thermostat bundles at a discounted rate when you buy a new boiler.
Factors That Affect the Price
- Location: Labour rates vary by region. London and the South East are 20% to 40% more than the North.
- Conversion type: Changing from a regular boiler to a combi involves removing tanks and cylinders, rerouting pipework, and potentially altering the flue route. This adds significant cost.
- Boiler position: Moving the boiler from an internal cupboard to an external wall, or from upstairs to downstairs, requires new pipework runs.
- Flue routing: If the existing flue position does not work for the new boiler, extending or rerouting the flue adds cost.
- System condition: Old, dirty heating systems may need a powerflush before a new boiler is installed to prevent sludge damaging the new unit.
How to Save Money on a New Boiler
- Stick with a like for like swap. Same type of boiler, same position. This is always the cheapest option.
- Get multiple quotes. Prices vary enormously. Three quotes minimum, and make sure they all include the same scope of work.
- Consider finance. Many installers offer 0% finance over 12 to 24 months. Spreading the cost means you can afford a better boiler.
- Buy online and have it installed. Some homeowners buy the boiler directly from a supplier and hire a Gas Safe engineer separately. This can save £200 to £500 but means you handle the warranty relationship yourself.
- Check the warranty. A boiler with a 10 year warranty often costs more upfront but saves money over a decade in repair costs. Worcester Bosch and Vaillant both offer up to 12 year warranties when installed by their approved engineers.
Red Flags to Watch For
- Not Gas Safe registered. It is illegal for anyone to install a gas boiler without Gas Safe registration. Check their registration number at gassaferegister.co.uk before they start any work.
- No survey before quoting. A reputable installer will visit your property to assess the existing system before providing a quote. A quote given over the phone or online without seeing the job is unreliable.
- Pushing the most expensive boiler. If an installer recommends the top of the range model without explaining why, they may be earning a larger commission. Ask them to explain the difference and why a particular model suits your property.
- No mention of a powerflush. If your existing system is old and has never been flushed, a new boiler connected to a dirty system will suffer premature failure. A responsible engineer will assess whether a powerflush is needed.
- Skipping the magnetic filter. A magnetic filter (£100 to £200) protects your new boiler from sludge and extends its life significantly. If the installer does not include one, ask why.
- No benchmark commissioning certificate. Every new boiler installation should include a completed Gas Safe notification and a Benchmark Commissioning Certificate. Without these, your warranty may be invalid.
A new boiler in the UK costs £2,000 to £4,500 installed for the most common scenarios. A straightforward combi swap is at the lower end. A conversion or relocation pushes towards the higher end. Get at least three quotes from Gas Safe registered engineers, check the warranty length, and do not be tempted to go with the cheapest quote without checking what is included. Also see our guide on plumber costs for related work.
Frequently Asked Questions
How much does a new boiler cost in the UK in 2026?
A new combi boiler installed costs between £2,000 and £3,500 for a straightforward like for like swap in the UK in 2026. A system boiler runs £2,500 to £4,500 installed. Converting from one boiler type to another or moving the boiler to a new location adds £500 to £1,500 to the total bill.
How much does a combi boiler cost to install?
A combi boiler costs £800 to £2,000 for the unit itself, plus £800 to £1,200 in labour for a like for like swap. Total installed cost is typically £2,000 to £3,500. Brands like Worcester Bosch and Vaillant sit at the higher end, while Ideal and Baxi are more affordable.
How much does it cost to replace a regular boiler with a combi?
Converting from a regular boiler to a combi boiler costs £3,500 to £5,500 in the UK including the boiler, labour, and removal of the old hot water cylinder and cold water tanks. The conversion involves rerouting pipework and takes 1 to 2 days.
How much do plumbers charge to fit a boiler?
Boiler installation labour costs range from £800 to £1,200 for a like for like combi swap, £1,000 to £1,500 for a system boiler swap, and £1,500 to £2,500 for a conversion from regular to combi. London rates are 20% to 40% higher.
What size boiler do I need for a 3 bed house?
A 3 to 4 bedroom detached house with 15 to 20 radiators needs a combi boiler with an output of 32 to 38 kW. A 2 to 3 bed semi with 10 to 15 radiators needs 28 to 32 kW. A good Gas Safe engineer will do a proper heat loss calculation rather than guessing.
How long does a new boiler last?
A well maintained boiler lasts 10 to 15 years on average. Annual servicing extends the lifespan and keeps the warranty valid. Boilers over 15 years old are significantly less efficient and more expensive to run than modern condensing boilers.
Is it worth getting a boiler on finance?
Many installers offer 0% finance over 12 to 24 months, which is a sensible option if it avoids you choosing a cheap boiler you will regret. Interest bearing finance over longer periods can significantly increase the total cost, so always check the APR and total repayable amount.
Should I get a boiler cover plan?
Boiler cover plans cost £10 to £30 per month and cover breakdowns and repairs. If your boiler is new with a manufacturer warranty, cover is unnecessary. For boilers over 5 years old without warranty, cover provides peace of mind but over 10 years costs £1,200 to £3,600, which could buy a new boiler.