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Best Boilers in the UK: Top 5 (April 2025)
- The ATAG iS is the best boiler overall, with its wide range of power outputs and outstanding warranty coverage.
- We compared around 150 boiler models from over 15 brands, considering their efficiency, affordability, brand reputation, and reliability.
- The best boilers in the UK cost between £850 - £4,500 and provide warranties of up to 12 years.
Are you on the hunt for the best boilers in the UK in 2025? Then you’ve come to the right place. In this guide, we’ll walk you through the top 5 on the market today. Currently, the best boilers in the UK are:
| Brand | Full product name | Boiler type | Overall GM rating | Best for |
|---|---|---|---|---|
| Baxi | 600 Combi | Combi | 4 | Best value for small homes |
| Baxi | 800 System | System | 3.5 | Best value for large homes |
| ATAG | iS | System | 4.5 | Best warranty |
| Viessmann | Vitodens 200-W | Combi | 3 | Highest efficiency |
| Ideal | Logic MAX Combi | Combi | 4 | Best reviews |
Below, you can find out more about each of these models and decide which boiler is best for your home. If you’re ready to upgrade your heating system, one of the main things to consider is that new boiler costs can be quite high, ranging from £540 and £3,500, excluding installation costs.
Thankfully, we can help you easily compare prices to avoid overspending on your new boiler. Just fill in our 30-second form and we’ll send you up to 3 quotes from local installers. It’s quick, easy, and completely free.
Click below to find the best deal for your home!
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How our experts selected the best boiler models
Our ranking takes a data-driven approach. We've considered key factors such as efficiency, warranty, price, and customer satisfaction. To ensure an objective comparison, we assigned a GreenMatch Rating to each boiler based on a formula.
We considered the following key metrics and scored boilers across the market accordingly:
- Efficiency – Higher efficiency means lower running costs and reduced energy waste.
- Warranty – A longer warranty indicates durability and manufacturer confidence.
- Price per kW – A fair cost relative to output ensures affordability and value for money.
- Trustpilot rating – Real customer feedback is a strong indicator of performance and reliability.
- Boiler type & suitability – Whether the model fits small or large homes effectively.
We normalised the data and assigned each category a score out of 5. The final GreenMatch Rating is the average of these scores.
Best boilers in the UK: Our top 5
The following models proved to have the most impressive results across the categories that we analysed. Take a closer look at their specifications in the table below:
| Brand | Full product name | Boiler type | KW Outputs/ Sizes | Efficiency | Warranty | Price range (inc. VAT) | Trustpilot rating |
|---|---|---|---|---|---|---|---|
| Baxi | 600 Combi | Combi | 24kW, 30kW, 36kW | 93% | 7 years | £850 - £1,000 | 4.6 |
| Baxi | 800 System | System | 18kW, 24kW, 30kW | N/A | 10 years | £1,200 - £1,900 | 4.6 |
| ATAG | iS | System | 14.7kW, 17.5kW, 23.2kW, 31.2kW | 93-94% | 12-years, options up to 18 years | £1,250 - £1,500 | 4.6 |
| Viessmann | Vitodens 200-W | Combi | 30kW, 35kW | 98% | Up to 7 years | £1,950 - £2,000 | 4 |
| Ideal | Logic MAX Combi | Combi | 24kW, 30kW, 35kW | 94% | Up to 10 years | £1,050 - £4,500 | 4.8 |
#1 Best value for smaller homes: Baxi 600 Combi
The Baxi 600 Combi 2 is compact and affordable, making it the perfect choice for smaller homes looking for great value for money.
| KW Outputs/ Sizes | Model names | Efficiency | Warranty | Price range (inc. VAT) | Brand Trustpilot rating |
|---|---|---|---|---|---|
| 24kW, 30kW, 36kW | 624, 630, 636 | 93% | 7 years | £850 - £1,000 | 4.6 |
With a price range of £850 - £1,000 and a 93% efficiency rating, this boiler provides excellent value for money while keeping energy bills low. Its small size allows for easy installation in homes with little space.
The Baxi 600 Combi offers hassle-free maintenance with its EasyFill System, allowing self-top-ups without an engineer. It works alongside the Baxi uSense smart thermostat for remote control, and it's winter-ready with a pre-heated condensate trap.
#2 Best value for larger homes: Baxi 800 System
Baxi also offers one of the best value boilers for larger homes. The Baxi 800 System goes up to 30kW, making it ideal for busy homes with high heating demands.
| KW Outputs/ Sizes | Model names | Efficiency | Warranty | Price range (inc. VAT) | Brand Trustpilot rating |
|---|---|---|---|---|---|
| 18kW, 24kW, 30kW | 818, 824, 830 | N/A | 10 years | £1,200 - £1,900 | 4.6 |
The Baxi 800 System offers a 10-year warranty for long-term reliability and works with a hot water cylinder, ensuring plenty hot water for multiple bathrooms.
It includes an Adey Micro 2 Filter for added system protection, supports smart thermostat control via the Baxi uSense app, and features a pre-heated condensate trap to prevent freezing in winter. It also has an external analogue pressure gauge for easy maintenance and it's compatible with natural gas and LPG.
Many customers appreciate Baxi’s efficient repair service. One customer noted that Baxi responded to faults within 24 hours and many highlight the professionalism of individual engineers. Another user praised Baxi for replacing a faulty part on the spot, just before a cold weather period.
However, the overall experience may vary as some customers had to wait a week for an engineer, only to be told the issue was a “common fault” and that they would need to wait even longer for a resolution.
#3 Best warranty: ATAG iS
The ATAG iS System Boiler stands out for its exceptional warranty coverage, making it one of the most reliable choices on the market.
| KW Outputs/ Sizes | Model names | Efficiency | Warranty | Price range (inc. VAT) | Brand Trustpilot rating |
|---|---|---|---|---|---|
| 14.7kW, 17.5kW, 23.2kW, 31.2kW | i15S i18S i24S i32S i40S | 93-94% | 12-years, options up to 18 years | £1,250 to £1,500 | 4.6 |
Every ATAG boiler comes with a 12-year warranty as standard, with options to extend up to 18 years, offering unmatched long-term protection. On top of this, its stainless steel heat exchanger comes with a lifetime replacement guarantee.
The iS system boiler delivers a steady supply of hot water for larger households. The in-built ErP pump optimises heat output, reduces energy consumption and saves you money on bills year after year.
The boiler is highly efficient and features built-in frost protection, making it reliable even in the coldest months. Plus, it operates quietly thanks to its bottom-up modulation technology.
Many users find ATAG boilers to be quiet and efficient. One customer noted that after almost two years, their boiler runs smoothly, keeps water at a stable temperature, and comes with a long warranty for peace of mind.
While many customers feel reassured by ATAG’s long warranty, installation problems have caused warranty disputes for some customers.
#4 Highest efficiency: Viessmann Vitodens 200-W
The Viessmann Vitodens 200-W sets the standard with a 98% ERP efficiency rating for minimal energy waste, reduced heating costs and a smaller environmental footprint.
| KW Outputs/ Sizes | Model names | Efficiency | Warranty | Price range (inc. VAT) | Brand Trustpilot rating |
|---|---|---|---|---|---|
| 30kW, 35kW | B2KE | 98% | Up to 7 years | £1,950 - £2,000 | 4 |
With the Lambda Pro Plus combustion controller, the Vitodens 200-W guarantees consistent high efficiency by automatically adjusting to changing gas qualities or types. This cutting-edge technology helps the boiler maintain its performance, even with varying gas supplies.
In addition to its high efficiency, the Inox-Radial heat exchanger, made from high-grade stainless steel, further ensures that energy is used to its fullest potential, extending the lifespan of the system and maximising heat conversion.
Users appreciate that Viessmann boilers operate with little to no noise, making them ideal for homes where loud systems would be disruptive.
While some customers had negative experiences, others praised Viessmann’s support team for their professionalism and quick responses. A number of users mentioned that the company arranged repairs efficiently and followed up to ensure satisfaction.
#5 Best customer reviews: Ideal
Ideal Boilers consistently ranks highly on Trustpilot, with a strong 4.8-star rating, proving the brand’s dedication to quality and reliability.
| KW Outputs/ Sizes | Efficiency | Warranty | Price range (inc. VAT) | Brand Trustpilot rating |
|---|---|---|---|---|
| 15kW - 40kW | 94% | Up to 12 years | £1,050 - £4,500 | 4.8 |
In addition to high satisfaction, the Ideal Logic MAX Combi boiler offers great value with features like a compact design, easy-to-read pressure gauge, and compatibility with smart thermostats like the Halo Combi Wi-Fi thermostat.
The Ideal Logic MAX Combi boiler is a standout product from a brand with a rich history of over 100 years of innovation in the heating industry.
The Logic MAX Combi offers 10 years of peace of mind with its comprehensive warranty and the added benefit of an Ideal System Filter, which protects the heating system and extends the boiler's lifespan.
Many customers praise Ideal Heating for efficient repairs. One customer was initially told they needed a full boiler replacement but had it repaired quickly by an Ideal engineer, saving hundreds of pounds.
Ideal Heating’s engineers are frequently praised for their professionalism. A customer mentioned how their issue was handled quickly and professionally, leaving them fully satisfied.
While some customers appreciate Ideal’s willingness to reinstate warranties, others feel that Ideal’s warranty service is unreliable.
Find the best boiler installers in the UK
Replacing your boiler is a big decision, but choosing the right one doesn’t have to be overwhelming. The best way to ensure a quality installation is to get multiple quotes from qualified engineers to compare prices and services.
Rather than spend hours searching up and down for the best installers to work with, let GreenMatch do the hard work for you. We can help you start your journey in just 30 seconds.
Simply fill in our short form, and you’ll receive quotes from up to 3 local boiler installers from our network. Our service is cost and obligation-free.
- Quotes from local engineers
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