A new boiler's average cost in the UK can range between £1,800 and £3,500 fully installed, with a straightforward combi boiler costing around £2,300. When you replace an existing boiler with a similar one, it typically costs less than a complicated installation. Choosing a system or regular boiler, opting for premium brands, or needing additional work like relocating the boiler or replacing the old pipework can raise the total installation cost to £4,000-£6,000 or more. The total cost depends on
- The type of boiler you choose.
- The brand and model you select.
- The amount of work required for the installation.
If your boiler is over 10 years old and consistently develops faults, especially during the winter season or starts leaking water, you might be considering whether to repair it or replace it with a new one. In this blog, you will discover the breakdown of costs so you understand how much a new boiler could cost before asking an installer for an estimate.
Boiler Installation Cost by Type
The type of boiler you select is one of the most important factors affecting the overall cost. In UK homes, there are three types of boilers that are commonly used. They differ significantly in price and suitability for different homes and hot water needs.
Combi Boiler Installation Cost
Combi (Combination) boilers are among the most widely chosen by UK homeowners because of their practical benefits. A combi boiler heats water on demand using water from the mains. They typically don't require a separate hot water cylinder or a cold water storage tank in the loft, which saves space. This makes them a practical option for smaller homes and flats.
In 2026, combi boilers usually cost:
- Budget Combi: £600-£900 (smaller outputs, basic controls)
- Mid-Range Combi: £900-£1,500 (better efficiency ratings, smarter controls)
- Premium Combi: £1,500- £2,500 (high output, smarter thermostat compatibility, extended warranties)
Replacement combi boiler cost, including the installer's labour, typically ranges from £1,500 to £3,000. The overall cost depends on the boiler model and how much work is required for installation.
Combi boilers are an ideal choice for houses with one bathroom and up to three bedrooms. A system or heat-only boiler may be a better option for you if your house has multiple bathrooms and a large household that may need hot water at the same time.
System Boilers
System boilers work with a separate hot water cylinder and typically include safety components, such as a pressure relief valve. In contrast to a combi boiler, they heat water that is stored in a separate hot water cylinder, which means several taps and showers can use hot water at once while the available flow rate is based on the system and water demand. Many key components are built into the boiler, making the installation process simpler than some traditional boiler setups.
A system boiler can be a perfect choice for a 4-bedroom house, especially for households with multiple bathrooms or higher hot water demands. The cost of a new boiler for a 4-bedroom house can range between £2,500 and £5,500 fully supplied and installed, depending on the type of boiler, the brand, and location.
System boiler units usually cost:
- Budget System Boiler: £800 – £1,200
- Mid-Range System Boiler: £1,200 – £2,000
- Premium System Boiler: £2,000 – £3,000+
You should also consider the cost of a hot water cylinder if you don't already have one. An unvented cylinder can usually add £500 to £1,000 to the installation cost. The total cost of buying and installing a system boiler typically ranges from £2,500 to £4,000. System boilers can be a suitable option for medium to large houses, especially those with higher hot water demands.
Heat-Only (Conventional or Regular) Boilers
Heat-only boilers are also called conventional or regular boilers. They are commonly found in older UK homes. They typically need a hot water cylinder and a cold water storage tank, usually kept in the loft. The cold water storage tank supplies water to the hot water cylinder, whereas the boiler heats the water. These boilers are often suitable for houses that already have this setup, as replacing the existing heating system with a combi or system boiler could involve unnecessary additional work and expense.
A heat-only boiler typically costs:
- Budget Heat-Only Boiler: £600 – £950
- Mid-Range Heat-Only Boiler: £950 – £1,300
- Premium Heat-Only Boiler: £1,300 – £2,200+
The total installation process can cost between £2,000 and £3,500 depending on the brand, output and region. Replacing a heat-only system with a combi can be more expensive and typically costs between £3,000 and £4,500. This is because the engineer may need to remove the cylinder and storage tanks, cap off the redundant pipework and make changes to the existing heating system.
Oil and LPG Boilers
People living in rural areas may use oil and LPG boilers as alternatives to gas boilers, especially where main gas is unavailable. These boilers are usually more expensive than their gas counterparts and typically cost between £2,500 and £5,000 installed, depending on the unit and amount of work needed. Oil boilers also need an oil storage tank on your property, which adds to the overall cost if you don't already have one.
What Affects the Cost of a New Boiler?
There are many factors that directly influence the overall cost of a new boiler. Some of these are listed below:
- Boiler Type and Output: A combi boiler with a higher heating output is typically required for larger homes, while compact models are often suitable for flats.
- Like-For-Like Replacement vs Conversion: Replacing the boiler with the same type in the same location is cost-effective. When you change the boiler type or move it to a different location, it can increase overall installation cost.
- Brand and Warranty: Premium boiler models and longer warranties can increase the overall price.
- Flue and Pipework: Additional work required, like installing a longer flue, flushing the heating system or replacing pipes, can directly influence the overall installation cost.
- Location: Boiler installation labour costs differ significantly by region. Installers in London may typically charge more than installers in other areas of the UK.
- Controls and Extras: A boiler installation package may include magnetic filters, smart thermostats and thermostatic radiator valves, which can enhance heating control and help protect the system.
How Do I Choose the Right Boiler Size?
A boiler's output is measured in kilowatts (kW). The boiler size should suit your home's heating needs instead of being chosen based on bedroom count alone.
| Property Size | Suggested Combi Output | Notes |
|---|---|---|
| 1-2 Bed Flat, 1 Bathroom | 24 – 27kW | Standard output is suitable for low demand |
| 3 Bed House, 1 Bathroom | 28 – 32kW | Commonly installed in the UK |
| 4 Bed House, 2 Bathrooms | 32 – 35kW combi or system boiler | System boiler ideal for simultaneous demand |
| 5+ Bed House, 3+ Bathrooms | System boiler with larger cylinder | Combi may struggle to meet peak demand |
An undersized boiler has difficulty keeping your home at the desired temperature and pressure on the coldest days. At the same time, an oversized boiler may switch on and off too often, wear out sooner and be highly expensive to buy and run.
How much is a new boiler for a 2-bed house?
In the UK, the cost of a new boiler for a 2-bedroom house usually depends on the type of boiler you choose, its output, the installation work needed and whether you are swapping an existing boiler or installing a different type.
For many 2-bedroom homes, a combi boiler is a practical choice as it offers heating and hot water without needing a separate hot water cylinder. But a system or regular boiler might be more suitable if your property already has hot water supplies.
Typical Cost of a New Boiler for a 2-Bedroom House
For a straightforward gas combi boiler replacement, you can expect to pay around £1,800–£3,500 supplied and installed.
Conclusion
A new boiler in the UK typically costs between £1,800 and £3,500 including installation. However, the cost can rise to £4,000-£6,000 or more when extra work is needed. The overall cost depends on the boiler type, brand, output and installation severity. Combi boilers are an ideal choice for smaller homes, whereas system and regular boilers could be a better choice for homes with higher hot water needs. Before choosing a new boiler, compare prices from expert installers and consider your home's heating needs, hot water demand and budget. A qualified heating engineer can help you select the right boiler size and provide full insight into the installation cost, which helps you make an informed decision.
Considering a new combi boiler for your home? MJ Plumber and Heating LTD helps you understand the installation process, explore suitable boiler options and estimate the overall cost. Get in touch today to discuss your requirements and ask for a boiler installation price.
