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Combi Boiler prices can vary hugely and depend on numerous factors, home size, output, brand, warranty, etc… but generally you can expect to pay anywhere between £500 to £1,500 for a new Combi Boiler—plus extra for installation.
When choosing a new Combi Boiler it’s important to get the right size and power output (kW output) relative to your home, this will ensure your Combi Boiler can sufficiently support your home’s heating needs.
Our ‘Combi Boiler Installation Price Guide’ lists suitable Combi Boiler options (for specific home sizes) together with particulars, allowing you to compare models, warranties and prices—we also detail certain installation (only) scenarios (see Combi Boiler Installation Prices) allowing you to gauge expected installation prices.
* This guide was designed to give you a quick idea of expected Combi Boiler and installation prices, however, we’d always recommend you seek advice from a qualified installer with regards to boiler size and output.
The following Combi Boilers are well suited to homes with 1–2 bedrooms, typically requiring a boiler output between 24kW and 27kW.
| Brand/Model | Size/Output | Efficiency | Warranty | Price |
|---|---|---|---|---|
| Brand: Worcester Bosch Greenstar 4000 | Size/Output: 25kW | A | Warranty: 10 years* | Price: £1,050 |
| Brand: Ideal Logic Max Combi | Size/Output: 24kW | A | Warranty: 10 years | Price: £950 |
| Brand: Vaillant ecoTEC Plus | Size/Output: 25kW | A | Warranty: 7–10 years* | Price: £1,150 |
| Brand: Baxi 800 Combi | Size/Output: 24kW | A | Warranty: 10 years | Price: £980 |
| Brand: Viessmann Vitodens 050-W | Size/Output: 25kW | A | Warranty: 7 years | Price: £900 |
* Extended warranties may require an accredited installer, registration, and annual servicing.
The following Combi Boilers are suitable for homes with 3–4 bedrooms, typically requiring a boiler output between 28kW and 34kW.
| Brand/Model | Size/Output | Efficiency | Warranty | Price |
|---|---|---|---|---|
| Brand: Worcester Bosch Greenstar 8000 Style | Size/Output: 30kW | A | Warranty: 10 years* | Price: £1,450 |
| Brand: Ideal Logic Max Combi | Size/Output: 30kW | A | Warranty: 10 years | Price: £1,050 |
| Brand: Vaillant ecoTEC Plus | Size/Output: 32kW | A | Warranty: 7–10 years* | Price: £1,350 |
| Brand: Baxi 800 Platinum+ | Size/Output: 33kW | A | Warranty: 10 years | Price: £1,100 |
| Brand: Viessmann Vitodens 100-W | Size/Output: 32kW | A | Warranty: 10 years | Price: £1,200 |
* Extended warranties may require an accredited installer, registration, and annual servicing.
The following Combi Boilers are suitable for larger homes with 4+ bedrooms, typically requiring a boiler output between 35kW and 42kW to meet higher hot water demand.
| Brand/Model | Size/Output | Efficiency | Warranty | Price |
|---|---|---|---|---|
| Brand: Worcester Bosch Greenstar 8000 Life | Size/Output: 35kW | A | Warranty: 10 years* | Price: £1,600 |
| Brand: Vaillant ecoTEC Plus | Size/Output: 38kW | A | Warranty: 7–10 years* | Price: £1,550 |
| Brand: Ideal Vogue Max Combi | Size/Output: 40kW | A | Warranty: 12 years | Price: £1,450 |
| Brand: Baxi 800 Platinum+ | Size/Output: 40kW | A | Warranty: 10 years | Price: £1,300 |
| Brand: Viessmann Vitodens 200-W | Size/Output: 42kW | A | Warranty: 10 years | Price: £1,650 |
* Extended warranties may require an accredited installer, registration, and annual servicing.
Combi boilers are often cheaper to install than conventional (heat-only) boilers because they don’t require a separate hot water cylinder or feed tank. They can also be fitted in a wide range of locations around the home.
Installation costs vary depending on whether you’re replacing an existing combi, moving the boiler, or converting from a system/regular boiler. The table below provides typical price ranges for common installation scenarios.
| Scenario | Typical Price (Installed) |
|---|---|
| Scenario: Replacing a Combi Boiler with a new Combi Boiler in the same location | Price: £1,800–£3,200 |
| Scenario: Replacing a Combi Boiler with a new Combi Boiler in a different location | Price: £2,200–£3,800 |
| Scenario: Replacing a System Boiler with a new Combi Boiler | Price: £2,500–£4,500 |
| Scenario: Replacing a Regular Boiler with a new Combi Boiler | Price: £2,700–£4,800 |
* Prices vary by property layout and installation requirements (flue position, condensate drain, gas pipe upgrades, controls, and labour time).
Combi boilers are a great option if you want to free up space in your home and you don’t regularly need high hot water flow to multiple outlets at the same time.
If your current boiler is unreliable, noisy, or expensive to run, replacing it sooner can help prevent breakdowns and improve efficiency. Many homeowners choose to upgrade during a wider refurbishment, as it can be easier to run new pipework, upgrade radiators, or improve heating controls at the same time.
It’s also worth planning ahead for colder months, as installer availability can be tighter during peak demand. Booking early can give you more flexibility and access to a wider choice of installers and appointments.
Our recommendations are based on installer feedback, proven reliability, warranty strength, and long-term running costs.
Installer-Rated Combi Boiler Picks
| Category | Brand / Model | Why It’s Recommended |
|---|---|---|
| Category: Best Overall | Boiler: Worcester Bosch Greenstar 4000 | Why: Excellent reliability, strong UK support network, long warranty options |
| Category: Most Reliable | Boiler: Vaillant ecoTEC Plus | Why: Proven engineering, quiet operation, excellent modulation and build quality |
| Category: Best Warranty | Boiler: Ideal Logic Max | Why: Long warranty periods and good value for money across the range |
| Category: Best Efficiency | Boiler: Viessmann Vitodens 100-W | Why: High efficiency, well-engineered components, strong reliability reputation |
| Category: Best Mid-Range | Boiler: Baxi 800 Platinum+ | Why: Good performance, long warranty, and wide installer familiarity |
* Need advice on your new Combi Boiler? then complete our Quick Quote Form, we'll then arrange for someone to contact you to discuss your requirements and budget further.
