If your boiler is old, unreliable or already costing too much to repair, you probably want one clear answer: how much does a new boiler cost?
In 2026, a new boiler supplied and fitted in the UK usually costs around £1,800 to £4,500.
For a straightforward combi boiler replacement in the same position, a realistic working range is often £2,000 to £3,500. More complicated work, such as moving the boiler, changing boiler type or replacing a back boiler, can cost £2,800 to £5,000 or more.
These are guidance ranges, not a promise of what your installation will cost. A Gas Safe registered engineer needs to inspect your home before giving you a reliable quote.
How much does a new boiler cost in the UK?
A standard new boiler installation usually costs between £1,800 and £4,500, including the boiler and fitting. Most like-for-like combi replacements sit towards the lower or middle part of that range, while relocations and system changes cost more.
Here is a useful 2026 guide:
| Type of work | Typical supplied-and-fitted cost |
|---|---|
| Like-for-like combi replacement | £1,800–£3,500 |
| New system boiler replacement | £2,200–£4,000 |
| New regular or heat-only boiler | £2,300–£4,000 |
| Combi boiler relocation | £2,500–£4,500 |
| System or regular boiler changed to combi | £2,800–£5,000 |
| Back boiler replacement or conversion | £2,800–£5,000+ |
The final price depends on the boiler output, the existing pipework, the flue route, access, your location and what extras are needed.
For comparison, current guidance from Gas Safe Register and consumer cost guides recommends getting a home survey and comparing written quotes rather than relying on an online estimate.
What does a combi boiler replacement cost?
A like-for-like combi boiler replacement normally costs £1,800 to £3,500, including the boiler, standard installation, flue and basic commissioning. A mid-range 28kW to 30kW combi replacement often falls somewhere around £2,200 to £3,000.
This assumes:
- The new boiler stays in the same position.
- Existing gas and water pipework is suitable.
- The flue can follow a straightforward route.
- No major system cleaning or remedial work is required.
- Standard controls and fittings are used.
A cheaper quote is not automatically better. Check the boiler brand, warranty, controls, filter, commissioning and aftercare before comparing totals.
Does a system or regular boiler cost more than a combi?
Usually, yes. A system or regular boiler installation often costs £2,200 to £4,000 because the system may include a hot water cylinder, cold-water tank, additional controls and more pipework. The right option depends on your home and water demand.
A combi boiler heats water directly and does not need a separate cylinder. It can suit smaller homes with one bathroom.
A system boiler works with a hot water cylinder. It can be useful for homes with more than one bathroom or higher hot water demand.
A regular boiler, sometimes called a heat-only or conventional boiler, usually works with a hot water cylinder and a cold-water storage tank.
Replacing an existing system or regular boiler like for like may be fairly straightforward. Changing it to a combi is a different job and usually costs more.
How much does a back boiler replacement cost?
Replacing a back boiler commonly costs £2,800 to £5,000 or more. Back boilers are often replaced with a modern combi or system boiler, which may involve removing the old unit, altering pipework and installing a new flue.
The price can rise when:
- The back boiler is behind a fireplace.
- The fire or surround needs removing.
- New pipework is required.
- The boiler is moved to a cupboard or another floor.
- The flue route is difficult.
- Walls, flooring or finishes need making good.
Ask the engineer to separate boiler, labour, removal and making-good costs. That makes it easier to understand what you are paying for.
What affects the cost of a new boiler?
The boiler itself is only part of the bill. Installation conditions often make the biggest difference to the final price.
Boiler size and output
Boilers are sold in different outputs, measured in kilowatts, or kW. A small flat does not usually need the same output as a large house with several bathrooms.
The engineer should calculate the required output rather than simply replacing the old boiler with the same size. An oversized boiler may cost more without giving you a useful benefit.
Like-for-like fitting or relocation
Keeping the boiler in the same position is normally cheaper. Moving it can require new gas, water and heating pipework, a longer condensate route, additional electrical work and a different flue arrangement.
A relocation commonly adds several hundred pounds, but the exact increase depends on distance and access.
Flue route and access
A simple flue through an outside wall is usually less disruptive than a longer or awkward route. The engineer may need extra flue sections, supports or access equipment.
Lofts, high walls, tight cupboards and difficult parking can all add labour time.
Magnetic filter
A magnetic filter catches metal particles in the heating system before they reach the boiler. It is often recommended with a new installation.
Allow roughly £80 to £200 if it is not already included in the quote. Some installers include a basic filter in their standard package, so check rather than assuming it is an extra.
Smart thermostat and controls
A basic control may be included. A smart thermostat or multi-zone control system usually costs more.
A new smart thermostat and installation often falls between £150 and £500, depending on the product and wiring required.
Power flush
If the system water is dirty or the radiators contain a lot of sludge, the engineer may recommend a power flush. This can cost around £400 to £600.
It is not automatically needed for every replacement. Ask what the engineer found and why the work is being recommended.
What should a new boiler quote include?
A proper quote should show the boiler model, output, warranty, labour and all expected materials. It should also make clear what is not included, so you are not comparing one low headline price with another complete installation.
Look for these items:
- Boiler make, model and kW output.
- Flue kit and flue installation.
- Labour and estimated installation time.
- Gas, water and heating pipework.
- Condensate pipework.
- Magnetic filter and inhibitor.
- Thermostat or heating controls.
- System clean or power flush, if required.
- Removal and disposal of the old boiler.
- Commissioning and warranty registration.
- Building Regulations notification.
- Any making-good work.
Ask whether the price includes VAT, parking, scaffolding, electrical work and disposal. Also ask when payment is due and whether the quote is fixed or subject to a further survey.
Why is an engineer survey better than an online boiler estimate?
An online estimate can suggest a broad price, but it cannot see your pipework, flue, access, boiler location or system condition. A home survey gives the engineer enough information to choose the right boiler and provide a more honest, itemised quote.
Before choosing an installer:
- Use the Gas Safe Register engineer search.
- Check that the engineer is qualified for domestic boiler work.
- Get two or three written quotes.
- Ask what is included and excluded.
- Keep the Building Regulations compliance certificate.
The Health and Safety Executive says gas work must be carried out by a Gas Safe registered engineer. Do not choose an installer solely because they give the lowest price.
Are new boiler prices higher in London and the South East?
Often, yes. Labour and operating costs can be higher in London and the South East, so a similar boiler replacement may cost 10% to 20% more than in a lower-cost area. This is a general guide, not a fixed regional rule.
The property itself still matters more than the postcode in many cases. A complicated installation in the North can cost more than a simple replacement in London.
Compare quotes based on the actual work, not just the headline figure.
What is the honest answer to “how much does a boiler replacement cost”?
For most UK homeowners, budget £2,000 to £3,500 for a standard combi boiler replacement in the same location. Budget £2,800 to £5,000 or more if you are changing boiler type, moving the boiler or replacing a back boiler.
Treat any online figure as a starting point. The only dependable price comes after a Gas Safe engineer has inspected the installation and explained the work.
How can heating engineers win boiler quote requests earlier?
Homeowners often search for the price before they search for a specific installer. Heating engineers who answer questions such as “how much does a new boiler cost?” clearly can build trust before the customer phones anyone.
Make your website explain:
- Typical boiler replacement price bands.
- The difference between combi, system and regular boilers.
- What changes the cost.
- What your survey includes.
- Whether you offer itemised written quotes.
- How customers can check your Gas Safe registration.
If you run a heating business, use the heating and gas engineers guide to see how local search and quote conversion fit together. You can also request a free VU1 audit. It checks 15 local, on-page and technical signals, takes under 15 seconds to request, and the report lands within a few minutes.
The £99/month VU1 membership combines ongoing visibility checks with an instant quote widget, helping customers find your business and take the next step once they land on your website.
Final answer: how much does a new boiler cost in 2026?
A new boiler in the UK costs around £1,800 to £4,500 supplied and fitted in 2026.
For a straightforward combi replacement, expect roughly £2,000 to £3,500. For a relocation, system change or back boiler conversion, allow £2,800 to £5,000 or more.
Get a Gas Safe survey, compare itemised quotes and check exactly what is included before you agree to the work.