Best Combi Boilers in the UK for 2024 | Heatable

For good measure, we’ll also tell you why you might not need the best combi boiler in the UK.

Like snails at a restaurant, some boilers just aren’t as bad as you think after a European has plastered them in garlic sauce…or quality in this instance

What makes a new boiler the best?

A brand name?
Boiler size?
Efficiency rating?

As home energy and gas prices rocket, we can make a strong case for the latter but who even is The Latter, and why are we protecting them in a strong case?

What is a combi Boiler? 

Combi boilers are the most popular type of boiler in the UK, primarily because they provide both heating and hot water from a single, compact unit. Ideal for most homes, combi boilers are efficient and space-saving solutions.

If you're in the market for a new combi boiler, you might be wondering how to choose the best model for your needs. In this article, our team of gas engineers and industry experts have thoroughly compared and analysed some of the top models of 2024, focusing on key performance factors.

What Is The Best Combi Boiler in 2024? 

Here’s a summary of the boilers we've reviewed, highlighting those that excel in key areas, which are discussed in detail further below:

• Best all-around combi boiler: Worcester Bosch Greenstar 4000

• Most affordable: Alpha NX Combi Boiler

• Best value for small homes: Worcester Bosch Greenstar 2000

• Best value for large homes: Vaillant EcoTec Pro 

• Most powerful combi boiler: Viessmann Vitodens 100-W

How Did We Choose the Best Combi Boilers? 

To identify the top combi boilers of 2024, our team of gas engineers evaluated several crucial factors:

• Warranty Period: Offered by the boiler brand, which serves as an indicator of durability.

• Brand Reputation: Based on customer reviews and assessments from industry experts, including our own team of engineers.

• Market Presence: Reflected by the number of sales within the UK.

• Awards and Recognition: Including industry accolades and honours.

• Which? Survey Results: An annual survey involving feedback from 10,000 homeowners and nearly 200 expert engineers.

• Aftercare Services: Provided by the manufacturer.

• Price Range: Of the various boiler models offered by the brand.

• Efficiency Ratings: Evaluating how energy-efficient the boilers are.

• Technological Features: Assessing the innovation and advanced features of the boilers.

• Availability and Cost of Spare Parts: Ensuring long-term maintenance is feasible and affordable.

These criteria helped us comprehensively assess and compare the performance and value of different combi boilers on the market.

Best Combi Boilers UK Comparison Table: 

In the table below you can compare the key metrics between some of the best combi boilers currently available in the UK: 

Table data: last updated July 2024. 

Best Combi Boilers (By Model) 

Below is our carefully curated selection of the best combi boilers from top UK manufacturers.

These models stand out for their exceptional customer reviews, long warranties, technical superiority, energy efficiency, robust heating capabilities, and award-winning aftercare support.

We prioritised brands with industry-leading support, as reliable aftercare is crucial when issues arise.

Join Thousands of Satisfied Customers:

We’re proud to be Which? Trusted Traders with over 10,000 glowing reviews on Trustpilot. Check out our Reviews and Testimonials page and watch Adrian’s video testimonial below to see why so many trust us for their heating needs.

#1 Best Combi Boiler - Worcester Bosch 4000 

When analysing the best combi boilers currently available we ultimately found the Worcester Bosch 4000 was the best all-around model available, here's why: 

Worcester Bosch has consistently ranked as one of the premier boiler brands in the UK market for decades, earning enduring trust among both installers and homeowners.

Notably, it has secured the prestigious Which? Best Buy Award for an impressive 14 consecutive years—a record unmatched by any other boiler manufacturer.

Customers frequently highlight the brand's reliability and efficiency and as of May 2024, they have a Trustpilot rating of 4.7 out of 5 based on over 17,000 reviews - a pretty impressive record. 

The Worcester Bosch Greenstar 4000 series represents the brand’s latest leap in innovation, succeeding their best-ever-selling boiler, the Greenstar i.

This model is specifically crafted to enhance the user experience in several key ways:

• Quieter Operation: Engineered to operate more quietly than its predecessor, the Greenstar 4000 ensures a less intrusive presence in your home.

• Compatibility with Smart Controls: This boiler is compatible with all Worcester Bosch controls and popular third-party controllers like Hive, Nest, and tado°, allowing for seamless integration into smart home systems.

• Optimal for Small to Medium-Sized Homes: Its design and capabilities make it ideal for smaller and medium-sized homes, offering efficient heating without the bulk.

• Ease of Maintenance: With removable side panels, the Greenstar 4000 is designed for easy access, simplifying maintenance and service tasks.

• Extended Warranty: It comes with a 10-year guarantee on parts and labour when purchased through Heatable, providing long-term peace of mind.

• High Energy Efficiency: With an ErP rating of 94%, it holds an A rating for energy efficiency, ensuring lower energy bills and reduced environmental impact.

• Compact Dimensions: Measuring 710 x 400 x 310 mm, it is compact enough to fit discretely within your home.

Prefer to watch instead? Check out our video roundup of the UK's best combi boilers below:

Why Choose the Worcester Bosch Greenstar 4000?

Choosing this boiler means investing in a product that combines Worcester Bosch's legacy of quality with the latest advancements in heating technology.

Consumers benefit from a system that not only meets but anticipates their heating needs, ensuring reliability, energy savings, and compatibility with the evolving landscape of smart home technology.

For homeowners looking for a durable, efficient, and user-friendly heating solution, the Worcester Bosch Greenstar 4000 presents an excellent choice that brings together the best of tradition and innovation in boiler technology.

Worcester Bosch is renowned for offering superb customer support and aftercare, which is another crucial reason why we placed this boiler model in the number one spot. 

As part of our analysis, when speaking with Allen Hart, a YouTube Gas Engineer with over 30 years of experience, he emphasised the importance of aftercare service:

Main features of the Worcester Bosch 4000 Boiler: 

• Worcester Bosch’s mid-range model

• Designed to have a quieter operation than the Greenstar i

• Compatible with all Worcester Bosch controls and third-party controllers such as Hive, Nest, tado etc.

• Ideal for small and medium-sized homes 

• Easy access with removable side panels

• 10-year guarantee on parts and labour (when purchased via Heatable) 

• ErP rating 94%: A-rated

• Dimensions: 710 x 400 x 310

#2 Best Combi Boiler - Vaillant EcoTec Pro 

Vaillant is a prestigious German boiler brand that is renowned for its reliability and high-quality engineering. 

Among installers, they are credited with being one of the "easiest boilers to repair".

Due to its superb reputation, Vaillant is the second-largest manufacturer of boilers in Europe today. 

Notably, in a distinct category of the annual boiler survey by Which? Vaillant emerged as the front-runner, earning a commendable 81% approval rating from 200 independent heating engineers for their gas boilers.

The brand's most popular range of combi boilers - the EcoTec Pro is offered in a variety of sizes including 24kW, 28kW and 30kW along with a 10-year warranty (when purchased via Heatable). 

Main features of the Vaillant EcoTec Pro 28:

Here are the main standout features of the Vaillant ecoTEC 28: 

• Hand-built in the Derbyshire-based plant in the UK 

• A complete range of thermostat controls

• Awarded the Which? Best Buy Award in 2016 

• Quiet Mark status - awarded to the quietest boiler models 

• ErP A rated for both hot water and heating efficiency

• Precision heating to reduce your fuel bills

• Dimensions: H 720 x W 440 x D 338 - compact design 

• Vaillant’s vSMART technology - control your heating from your smartphone 

#3 Best Combi Boiler - Alpha E Tec NX

A relatively new brand in the UK boiler market, in recent years Alpha has built a reputation for offering affordable boilers that don’t cut corners when it comes to reliability or quality. 

The Alpha E-Tec NX is one of the brand’s best-selling combi boilers, offering a level of quality to rival premium brands but at an extremely reasonable price point. 

Main features of the Alpha E-Tec NX Boiler:

• Alpha’s best-selling combi boiler 

• Designed to neatly fit into small spaces like kitchen cupboards 

• Easy access front panel making servicing quick and easy 

• Built with a stainless-steel heat exchanger 

• Compatible with all leading third-party controls such as Hive, Nest, tado etc.

• High-efficiency Grundfos pump and hydro lock assembly

• Zinc-plated expansion vessel to prevent corrosion

• 10-year guarantee on parts and labour (when purchased via Heatable) 

• ErP rating 93%: A-rated

• Dimensions: 712 x 440 x 255

• Good Homes Magazine Approved (2024) 

#4 Best Combi Boiler - Viessmann Vitodens 100-W 

The Viessmann Vitodens 100-W is the best-selling combi boiler from the award-winning brand and has an impeccable reputation. 

Viessmann was previously awarded the Which? Best Buy Award from 2017 to 2020 and since their introduction to the UK market has made continued efforts to improve the availability of spare parts. 

The Viessmann Vitodens 100-W comes in a pretty compact size for a wall-mounted combi boiler.

Our Head of Sales, Phil Cox, has a special preference for this combi boiler, leveraging his extensive experience as the former Director of Sales at British Gas.

Its compact size allows it to fit in most standard kitchen cupboards and ensures it isn’t an eyesore when installed in a living space.

Main features of the Viessmann Vitodens 100-W Boiler: 

Before we get into the details, here are some of the most notable features of the Viessmann Vitodens 100-W model (most recent 2024 model): 

• Class 'A' for energy efficiency

• 12-year comprehensive warranty as standard - when purchased with Heatable

• 92% efficiency

• Hydrogen-ready for the next generation of fuel 

• Weather compensation option for Boiler Plus compliance

• Backlit LCD touchscreen display 

• Stainless steel heat exchanger 

• Compatibility with the Viessmann Vitronic smart thermostat - that sounds fancy

#5 Best Combi Boiler - Ideal Logic+ 

Founded in 1906, Ideal is a UK-based boiler brand (that also ranked #4 in our top 10 boiler manufacturers) that has built a reputation for offering competitively priced, reliable boilers and in recent years - becoming the mascot of West Bromwich Albion F.C. (a.k.a Boiler Man).

The Ideal Logic Combi 30 is one of Ideal’s bestselling combi boilers from their entry-level Logic range, offering a balance of all the essential features, reliability, and a very reasonable price point.

Main features of the Ideal Logic Combi Boiler: 

• Made in the UK 

• Compact in size (ideal for cupboards) 

• Won the Queens Award in 2013 

• Won Good Housekeeping Awards 2013 & 2017 

• Quiet Mark Certified - an award for especially quiet appliances 

• 10-year parts and labour warranty (when purchased via Heatable) 

Have issues with your combi boiler? Read our boiler problems and solutions for quick troubleshooting guidance. 

Best Combi Boilers of 2024 (By Brand)

Here are our top 6 best combi boiler brands in the UK right now, in 2024:

• #1 Worcester Bosch Combi Boilers

• #2 Vaillant Combi Boilers 

• #3 Alpha Combi Boilers

• #4 Viessmann Combi Boilers

• #5 Ideal Combi Boilers

• #6 BAXI Combi Boilers

#1 Worcester Bosch Combi Boilers (Best boilers)

A prestigious name within the heating industry and probably the UK’s best, most sought-after combi boiler, historically. One of three combi boilers with the Which? Best Buy award and you can’t go far wrong with a Worcester.

Why do we think Worcester offers the best combi boilers? 

• Which? Best Buy Award for over 10 years 

• 10-year guarantee (when purchased via Heatable)

• Availability of parts is second to none 

• Excellent customer reviews and aftercare 

Want a new Which? Best Buy boiler with professional installation?

You can see the latest price on Worcester Bosch boilers here.

Worcester 2024 combi boiler range & overviews:

Greenstar 2000 Combi Boiler

The brand's entry-level offering. 

The Worcester Bosch 2000 is the brand's entry-level combi boiler and is officially their quietest model to date.

It is designed to fit into small spaces e.g. kitchen cupboards and features easy-to-remove side panels for convenient servicing and maintenance. 

Like all of the latest boilers from the brand's updated Greenstar range, the 2000 also benefits from the super sleek, contemporary design and digital interface. 

Ideal for: Those looking for an entry-level, super-quiet boiler from an award-winning brand.

Boiler specifications: 

• Warranty: 5 years standard or up to 10 years when installed by Heatable

• Energy efficiency rating: A

• Output rating (kW): 25, 30

• Water flow (litres/min): 16.4

• Size (mm): 700 x 300 x 400

Greenstar 4000 Combi Boiler (Best all-around combi boiler)

The brand's mid-range combi boiler.

The Greenstar 4000 is a brand new arrival to the Worcester Bosch range of combi boilers, designed to replace the best-selling Greenstar i range.

The Worcester Bosch 4000 offers everything the i range did but with some major improvements, including a quieter operation and a higher hot water output. 

The 4000 benefits from a new, sleek curved edge case, user-friendly digital display and easy-to-use push control buttons, a major improvement on the boring square boxes of old.

Read our complete, in-depth review of the Worcester Bosch 4000 here. 

Ideal for: Those looking for a mid-range boiler from an award-winning brand. 

Boiler specifications: 

• Warranty: 5 years standard or up to 10 years when installed by Heatable

• Energy efficiency rating: A

• Output rating (kW): 25, 30

• Water flow (litres/min): 16.4

• Size (mm): 710 x 310 x 400

Greenstar i Combi Boiler (Best combi boiler in terms of sales)

The Greenstar 30i is Worcester’s best seller and over a million of them are in homes throughout the UK. If choosing between the two, then do consider opting for the Greenstar 30i over the Greenstar 25i as they are known to be much more reliable and often don't have too much disparity in price.

If you do have a super small property though, then the 25i will be more than adequate and could secure you a hell of a Worcester bargain.

Note: This boiler has now been replaced by the new and improved Greenstar 4000 (listed above). 

CDi Compact Combi Boiler

A combi boiler designed for small spaces. 

Another range-topper from Worcester Bosch boilers with more compact dimensions for homes short on space. The CDi compact is still complete with outstanding efficiency levels, a Which? Best Buy award and can still pack a punch for its size – comfortably powering homes with two bathrooms.

Ideal for: Ideal for: Those looking for a powerful and compact boiler that can squeeze into a tight spot e.g. kitchen cupboards.

Read our in-depth Worcester Bosch Greenstar CDi Compact Review.

Worcester Bosch 8000 Style (Replacing the CDi Classic) 

The brand's premium combi boiler model.

Worcester's most powerful and connected wall-hung boiler to date, capable of delivering up to 50kW's, and with optional smart technology that will top up the boiler for you when low pressure is detected.

As its name suggests, it is also arguably the best-looking boiler on the market and readily available in black - a boiler industry innovation on par with the introduction of the iPod.

Ideal for: Ideal for: Those looking for a top-of-the-range boiler, with all of the latest and greatest features.

Read our in-depth reviews of some of the most popular models from the brand: 

• Worcester Bosch 2000 Combi Boiler Review. 

• Worcester Bosch 8000 Combi Boiler Review. 

Learn all about combi boilers in our what is a combi boiler guide and see how the brand fared against Baxi in our Worcester Bosch vs Baxi comparison. 

Greenstar Si Compact Combi Boiler

Very similar to its namesake, the Greenstar Si boasts almost identical statistics and features and again is suitable for small to medium homes with one bathroom but a smaller frame allows this model to nestle into a kitchen cupboard – it's probably the best option if you require your combi boiler to be out of sight.

Ideal for: Those looking for a powerful boiler that can fit into small spaces. 

Check the latest deals on Worcester Bosch boilers here. 

CDi Classic Combi Boiler (Discontinued)

A truly premium boiler from Worcester and their top-of-the-line offering, in their opinion, it's probably the best combi boiler in their range.

If you have your heart set on a Worcester then this is certainly one model to consider, although it may come with a more premium price tag.

Note: The CDi Classic has been replaced by the Greenstar 8000 (listed above). 

Have you had a boiler quote yet? Use our calculator to get an instant new boiler quote. 

CDi Highflow Combi Boiler

A monstrous floor-standing combi boiler with industry-leading hot water flow rates. Perfect for large homes with multiple bathrooms that don’t want to make way for an additional water tank. It's the best combi boiler for massive homes, not many can match its credentials.

Ideal for: Those looking for a combi that can handle super high hot water demands. 

Do you have a large home? You may be interested in reading our guide on the best 40kW combi boilers

Worcester the way? We think so.

Worcester Bosch boilers are without a doubt one of the best combi boiler brands in terms of reliability and you can bag yourself a 10-year warranty (assuming you buy from a Worcester Approved Installer and not a rogue in an unmarked white van) giving you peace of mind no matter what.

Check the latest price on a Worcester boiler here. 

If you purchase a new Worcester Bosch boiler via Heatable, you will indeed secure yourself a lengthy 10-year guarantee. 

If you’re hellbent on getting a Worcester and quality is your top priority, you may want to consider exploration beyond the Greenstar i range - where Worcester's real quality lies - the 8000 Style is a great place to start.

However, unlike other manufacturers, irrespective of your chosen Worcester Bosch model - you can always bank on Worcester's outstanding aftercare which is without a doubt, industry-leading.

You can check the latest deals on Worcester Bosch boilers here, and see how the brand compared to another market leader in our Worcester Bosch vs Vaillant Boilers post. 

They're award-winning boilers: Voted Which? Best Buy for 10 consecutive years

As one of the most credible and respected consumer awards - it's an award, unlike others, that you simply can't buy.

The brand won the “Best Buy” award based on feedback from actual real humans (not pretend ones). They also gathered feedback from over 100 installers.

Moreover, the brand's boilers received several high 5-star ratings the consumer choice organisation considers most important to consumers, including full marks for their build quality and availability of parts and spares.

If your Worcester Bosch boiler's losing pressure, get a fixed price replacement, online.

How much will the installation of the best combi boilers cost? Check out our new boiler costs guide for the full rundown.

What factors do you need to consider when having a new combi fitted? Find out in our combi boiler installation guide. 

#2 Vaillant Combi Boilers (2nd Best Combi Boilers)

Another proud owner of a Which? Best Buy award and a huge player in the British boiler market. Vaillant is a time-served and well-respected boiler manufacturer and is certainly among the premium contenders.

Vaillant combi boilers are made in the UK to impeccably high standards, they’re already in a staggering amount of UK homes, offer excellent warranties, and are loved by boiler installers too.

Did you know that you could pay for your money in monthly instalments using boiler finance options. 

Vaillant's 2024 combi boiler range & overviews:

Vaillant ecoTEC Pro Combi Boiler

Vaillant's entry-level combi option. 

The perfect combi boiler solution for small to medium homes with the kW model’s coming in three different outputs to suit all.

A bright LCD display makes the ecoTEC pro super simple to use and it also comes with a Quiet Mark award so it’s not going to wake you up whilst warming your home in the morning.

Ideal for: Ideal for: Those looking for Vaillant's entry-level combi boiler.

Vaillant ecoTEC plus Combi Boiler

The brand's mid-range combi model.

A broad range of kW outputs starting from 25kW makes Vaillant’s ecoTEC plus the combi allrounder for almost any small to medium home.

Excellent efficiency ratings, premium components and the addition of the Quiet Mark award for quiet operation make this Vaillant’s flagship boiler.

Ideal for: Ideal for: Those looking for Vaillant's entry-level combi boiler.

Ideal for: Anyone looking to secure themselves Vaillaint's mid-range or so-called 'flagship' combi. 

Vaillant ecoTEC exclusive Combi Boiler

The brand's premium offering.

Available in outputs at the higher end of the scale -35kW and 43kW, the ecoTEC exclusive is a premium combi boiler for larger homes that boasts an impressive 17 litres of hot water per minute.

Indeed impressive if you like lotsa' hot water.

Ideal for: Those looking for a powerful combi boiler with a durable stainless steel heat exchanger and built-in energy-saving tech.

Vaillant ecoTEC plus store Combi Boiler

A combi with built-in water storage. 

It's a beast of a storage combi boiler that’s premium in every manner.

A hot water delivery rate of up to 20 litres per minute that you would struggle to find elsewhere makes this an outstanding choice for larger homes if you don’t want to, or have the room to fit an additional water storage tank.

Ideal for: Those with high hot demands, looking for a combi boiler that can handle it, equivalent to the Viessmann 111.

Curious to know which condensing boiler brand performed worst? Find out in our report on the worst boilers. 

Vaillant ecoFIT pure Combi Boiler

The brand's super-compact model.

Another super-efficient combi boiler suitable for almost any sized home with the added bonus of being extra compact, if you’re shy on cupboard space or a boy wizard, lives under your stairs.

It’s clever too – automatically reducing its energy usage to lower your bills.  

Ideal for: Those looking for a super-compact combi boiler that can squeeze into cupboards. 

Order today & get your Vaillant installed tomorrow: 

If you’re considering a new Vaillant boiler, smart choice. Vaillant is a time-tested boiler brand with an impeccable reputation and collection of awards. 

Recommended: Check out our top 10 list of the best boiler manufacturers for a complete rundown on the best combi boilermakers. 

If you are interested in the Vaillant ecoTec get a fixed price on a brand new model with gas-safe installation as quickly as tomorrow. 

Got an emergency? If your boiler is busted and you have no hot water, you may be interested in our emergency boiler installation guide. 

Do you have a Vaillant and are experiencing the F28 code? Read our full guide on the Vaillant F28 error. 

#3 Alpha Combi Boilers (3rd Best Combi Boilers)

Alpha Innovation or simply Alpha boilers are a relatively new brand in the UK's domestic boiler market but has quickly made a name for itself, thanks to their reliability and affordability. 

Made in the heart of Italy and with a headquarters based in Kent, this manufacturer offers a comprehensive range of boilers that on a technical level rival market leaders. 

There's no doubt that Alpha offer the top combi boilers for those on a budget. 

Why else do we think Alpha boilers are a great choice? 

• Good Homes Magazine Approved.

• 10-year guarantee (when purchased via Heatable).

• Superior build at an affordable price point.

Alpha's 2024 combi boiler range & overviews:

Alpha NX Combi Boiler 

Alpha's most popular combi boiler.

The Alpha NX is the brand's latest combi boiler, replacing their best-selling Alpha E Tec and offers a level of quality to rival premium manufacturers but at a budget-friendly price point. 

For example, they utilise a stainless-steel heat exchanger which is usually something you would only expect in a premium brand. 

Alpha offers a warranty of 7 years on their Alpha NX, but Heatable offers an exclusive 10-year warranty, which also matches some of the premium brands. 

Ideal for: Those looking for high quality and reliable boiler at an affordable price point. 

Interested in the Alpha E-Tec NX? Get a fixed price on a brand-new model with gas-safe installation as quick as tomorrow. 

#4 Viessmann Combi Boilers (4th Best Combi Boilers)

Viessmann is already an astronomical force in the European boiler market and also leads the way in commercial boiler installations.

Now they’re here to bestow their majestic German engineering upon the UK domestic market providing your home with a new boiler so good, you can forget about it for good this time.

Why do we think Viessmann offers some of the best combi boilers? 

• Which? Best Buy Award winner - titled as the UK's "most reliable boiler".

• 10-year warranty (when purchased via Heatable).

• State-of-the-art German engineering - no plastic or rubber components (like some competitors).

• Patented Inox Radial Stainless Steel Heat exchanger (not aluminium found in inferior brands).

• The only boiler with Lamda combustion control - maximising efficiency.  

• Hydrogen ready - for the next generation of fuel.

• The availability of parts is second to none.

• Excellent customer reviews and aftercare.

Want a new Which? Best Buy boiler with professional installation?

You can see the latest price on Viessmann boilers here.

Viessmann’s 2024 combi boiler range & overviews:

Boiler not working? Fancy a Viessmann? Get your fixed price online. We can install it in as little as 24 hours.

Viessmann Vitodens 050-W Gas Combi Boiler

The brand's entry-level offering.

Available in two kW outputs suitable for any home requiring a new combi boiler, the Viessmann Vitodens 050-W is the trusty workhorse of the Viessmann family.

It has a price to compete with boilers that don’t scratch the surface of its quality whilst maintaining high component standards – most importantly of all, their patented Inox-Radial stainless steel heat exchanger (essentially a part in other boilers that’s likely to break and Superman would struggle to crack this one). 

Oh – and it has a Which? Best Buy award, only bestowed on the greatest of boilers and in response to feedback from thousands of real customers and industry experts. 

Ideal for: Those looking for an entry-level model from an award-winning brand. 

Like the Viessmann Vitodens 050-W? Get a fixed online price, including installation as quick as tomorrow.

Viessmann Vitodens 100-W Combi Gas Boiler

The brand's mid-range combi boiler with a powerful punch.

Everything that makes its little brother Vitodens 050-W the super boiler it is and more. The Viessmann Vitodens 100-W should be any homeowner's go-to combi boiler.

A familiar endorsement from ‘Which?’ for its remarkably high-end internal parts, a class A rating for efficiency, back-lit LCD display, low fan speed for quiet operation and low CO2 emissions to help ease your carbon footprint and conscience. This is Viessmann’s, Lebron James.

Upgrades on the 100-W vs the 050-W include a larger LCD display with additional options, a superior Printed circuit board (essentially the brain of the boiler) and additional power output options. 

The 100-W is also manufactured and assembled in the German Viessmann factory, while the 050-W is assembled in Turkey. 

Ideal for: Those looking for a powerful, mid-range combi boiler. 

Viessmann Vitodens 200-W Combi Boiler

The brand's range-topping boiler model is perfect for larger homes. 

Meeting every demand a boiler buyer could possibly have for their combi boiler.

The Vitodens 200-W is perfectly suited for larger detached and semi-detached homes.

It holds every feature and perk of Viessmann boilers before it whilst also boasting a colour touchscreen display, smart thermostat compatibility and up to an incredible 98% efficiency rating.

Ideal for: Those looking for the top-of-the-range combi boiler from the award-winning German brand. 

Like the Viessmann Vitodens 200-W? Get a fixed online price.

Check out our full guide on choosing a boiler for a large home. 

Viessmann Vitodens 111-W Storage Combi Boiler 

A combi with built-in water storage, ideal for homes with high hot water demands. 

The only thing Viessmann can be accused of is a lack of imagination when it comes to naming their boilers, but their quality does all of the talking.

The Vitodens 111-W is a monstrous storage combi – essentially rendering it a kind of beautiful Frankenstein boiler – halfway between a combi and a regular boiler delivering a ludicrous 18 litres of hot water per minute.

Lucky enough to have that huge house you always wanted? Get luckier and get yourself the Vitodens 111-W.

The 111 boiler model can fill a bath in just 8 minutes while simultaneously supplying a sink or washbasin. 

Ideal for: Those looking for a boiler capable of meeting extremely high hot water demands, without the necessary space for a system boiler and tank. 

Like the massive Viessmann Vitodens 111-W Storage Combi hybrid? Get a fixed online price.

Typical Viessmann Combi boiler prices 2024 (ours are the best!):

Please note: The above prices assume a straightforward swap of a new, replacement combi boiler. To get the best accurate price, click the get quotes button. Or, for a massive, in-depth article on prices, check out our new boiler costs article.

If time eluded you and you didn’t have time to read the life-changing Viessmann overview above, then do read this brief conclusion.

Want to save money and energy on your heating bills? If so, you should consider installing one of the best smart thermostats.  

What's more, Viessmann offers some of the best boilers in class when it comes to efficiency too.

The Energy Saving Trust make it clear:

If Viessmann's really are the best gas combi boiler, why are they so cheap?

Heatable has a unique business model, allowing us to offer all our Viessmann’s with a 12-year warranty at mind-bogglingly low prices.

But truthfully – Viessmann boiler prices will very shortly be on the rise and such bargains are much harder to come by.

Right now, Viessmann is priced so well to increase their exposure to Britain’s domestic boiler buyers but as their quality becomes more than just rumour – their prices will inevitably rise to reflect just how premium of a product they really are.

The best combi boiler of 2024, may soon become the most expensive.

Viessmann Boilers sponsor Huddersfield Football Club and since this engagement, the Huddersfield players have been so distracted by the beautiful heating machines in their homes, that they’re practically guaranteed relegation from the Premier League this year – all without a care in the world. That’s the power of Viessmann.

*2024 update - Huddersfield were indeed, relegated. 

Viessmann boilers' quality comes from within – literally. A boiler is the sum of all its parts and internal components that make or break them.

Viessmann never compromises on the quality of their build - it’s a German thing. They only accept the best. Their boiler range is littered with endorsements from Which? all so readily backing up their already unrivalled features and statistics.

Did you know our boiler installation cost calculator only takes 60 seconds to complete? Using a series of multiple-choice questions, it can provide you with a fixed price on a range of budget-friendly boilers. 

Did we mention that Viessmann is the UK’s most reliable boiler? If nothing else swings it for you, that alone, should.

Don't just take our word for it either...

Convinced that the Viessmann combi range is the best for you? Get a fixed online price today and get your installation as quickly as tomorrow.

Read our Worcester Bosch vs Viessmann Boilers review if you need some help in choosing between these two popular brands.

Do you have limited space in your home? Check out our guide on the best small boilers.

Want the exact price of a new boiler? Use our boiler quote calculator (your fixed price will appear on the screen).

#5 Ideal Combi Boilers (5th Best Boiler Brand)

Joyful wordplay aside, an Ideal combi boiler might just be the ideal boiler for your home.

Ideal boilers have been a mainstay in the British boiler market for what seems like an eternity. Picture a horse that relentlessly finishes in the top 6 at the Grand National but never quite gets its nose in front – no cigar but you know that horse is from a damn good stable.

Ideal is all about inclusivity and range – their combi boilers range from budget to bedazzling and everything in between meaning they cater to the folks funding their boiler replacement with change found down the side of their couches, as well as those looking for the best boiler money can buy (see; Ideal Vogue).

Ideal’s 2024 combi boiler range & overviews:

Do you have a back boiler and want it replaced with a modern combi boiler? Ideal looking like an ideal choice? Get a fixed online price

Ideal Logic Combi Boiler

The brand's entry-level combi boiler. 

Ideal, Logic, Vogue. Ideal’s marketing team don’t like unnecessary syllables and loves assigning words to their products that already hold positive connotations.

Fortunately, their technical team do tend to back this up.

The Logic combi is without a doubt a logical choice for any grudge purchase boiler installation.

Are the odds of your boiler breakdown being expected and affordable? We’ve checked, and it’s 3%. The Ideal Logic is a no-thrills, solid boiler that’s popular for its price-to-quality ratio. Ideal offers a 2-year standard warranty providing you with the required peace of mind – not bad for a dual award winner.

Ideal Logic combi's best boiler perks:

• Made in the UK - so you know it's good

• Compact in size (ideal for cupboards)

• Roughly as difficult to program as peeling a banana

• Won the Queens Award in 2013

• Won Good Housekeeping Awards 2013 & 2017

• 2-year warranty as standard 

Want the best price on a new Combi Boiler? Get a fixed online price with installation within 24 hours.

Ideal Vogue Combi Boiler

Their mid-range model.

Weary of churning out their regular award-winning boilers, Ideal set out to make a boiler to break the mould.

The Ideal Vogue Gen2 is Ideal’s best, premium offering, also picking up numerous awards, it has been blessed with internal component upgrades, a backlit LCD colour display, a standard 10-year warranty, built-in frost protection and an endorsement from the Energy Saving Trust for its outstanding efficiency and global warming protest organisational skills.

Ideal Vogue Max Combi Boiler

Ideal's range-topping combi option.

If it isn't broken, don't fix it. Ideal to know that it's just plain logic. So their Vogue Max is just their regular Vogue but with an added Ideal-approved water filter, magically increasing their already whopping 10-year warranty to an unprecedented and industry-leading, 12 years. It's the best combi boiler in its class in terms of warranty length vs. cost.

Read the Ideal Vogue Max Combi Boiler Review. 

A note on the head-turning, heart-breaking, bone-chilling aesthetics of the Ideal Vogue:

Typical Ideal Combi Boiler prices (we offer the best online prices, period!):

Please note: The above prices assume a straightforward swap of a new, replacement combi boiler. To get the best accurate price, click the get quotes button.

For the best budget combi boiler, as of 2024, we would recommend the Alpha E Tec, but for those looking for something a little more premium, then the Viessmann or Worsceter range is certainly worth looking into. These are some of the best boiler brands available, and that's why we fit them. You won’t find a better combi boiler in the Alpha boilers range in 2024.

#6 BAXI Combi Boilers (6th Best Combi Boiler)

Nobody has ever been struck with such elation after being offered a BAXI boiler that they’ve moonwalked to work the next day and offered their colleagues a poorly baked lemon drizzle cake – but perhaps they should.

Baxi might not be considered amongst the premium boilers of the market but they certainly have some premium products backed up by award-winning customer service and excellent warranties so if you’re looking for a bargain, you might just find it in a BAXI.

BAXI combi boiler range & overviews:

We know what you're thinking:

Baxi has more combi boilers than we would care to run through but if you’re looking for top quality and aiming for that reassuring 10-year warranty mark, make sure you aim for the Baxi 600, the Baxi duo-tec, the Baxi EcoBlue range or the Baxi Platinum.

Consider avoiding the Baxi 100, 200 & 400 range if you’re looking for a premium standard and long warranty.

If your radiator is cold at the bottom, it may be a sign of a faulty boiler valve, in which case getting your new boiler replaced may be appropriate, check out the Worcester Bosch Greenstar 30i, which you can purchase through us. 

Interested in a Baxi? Read our Baxi Duo Tec 28 Combi boiler review and the Baxi 600 Combi boiler review. 

Best Combi Boilers - Our Summary

This guide's purpose is to help you make an informed decision about your new boiler purchase. Let's face it, you aren't going to be buying a new one that often, so you want to ensure it lasts the test of time. 

That's why the boilers we have presented have been thoroughly vetted based on the factors that truly matter: reliability, customer reviews, availability of parts, price range, and efficiency ratings. 

If you think your boiler is at the end of its life, then it usually makes financial sense to get it replaced sooner rather than later, since repair costs can quickly start to mount. Not only that but modern A-grade boilers offer superior efficiency, helping you save more money on your heating bills.

The best gas boilers offered by leading manufacturers such as Worcester Bosch and Viessman will also come with a brand new warranty (or guarantee in the case of Worcester), so you can have the peace of mind that if something does go wrong, you'll be covered - sometimes for as long as 10 years. 

Best central heating boiler

The best central heating boilers on offer in 2024 are: 

• #1 Viessmann Vitodens 100-W Combi Boiler 

• #2 Vaillant EcoTec Plus Combi Boiler

• #3 Alpha E Tec Combi Boiler

These boilers are particularly good since they are available as both system boilers and combi boilers. 

The above boiler manufacturers have been recommended based on their quality, reputation, and customer reviews. 

For instance, Worcester Bosch has been a Which? Best Buy award winner for 10 consecutive years, offers a 10-year guarantee and has been a reputable brand in the UK for generations. 

Viessmann is another high-quality boiler brand, offering impeccable German engineering, while Alpha is an excellent value boiler brand, that offers technical superiority for its price point. 

Read our complete guide on central heating boilers to learn more. 

Best combi boiler by property type

Batman would be pushing it if he wanted a combi boiler for Wayne Manor.

Fortunately, though, modern combi boilers will be perfect for almost any home – from 1-bedroom flats to 6-bed detached houses.

Please note: The exact boiler suitable for your home depends on a variety of factors unique to your situation. 

• Find out what boiler is best for you along with costs (takes 60 seconds) »

But, if you've got a whopping great mansion with multiple bathrooms and shower units, we'd suggest you look for an alternative. For homes of that size, you'd be better off looking at quotes for a new regular or system boiler.

They store hot water in large tanks (separate from the boiler) and feed the water outlets at an even rate. If you had a combi boiler, and you tried to run 3+ baths at the same time, it'd likely trickle out rather than blast.

Here’s a glance at which combi boiler is best for your home in 2024:

Best combi boiler for a small flat/apartment

Best Boiler: Worcester Bosch Greenstar 25i
Best Boiler Size: 25kW

25 Kilowatts of pure Ideal will perform well for smaller properties, providing heat and hot water on demand. It’s also backed up by outstanding customer reviews and through Heatable, packs a whopping 5-year warranty.

Best combi boiler for a 2-bedroom house

Best Boiler: Worcester Bosch Greenstar CDi Compact
Best Boiler Size: 28kW

A 28kW CDi Compact with a 10-year warranty effortlessly glides into a 2-bedroom home. It’s the manufacturer's bestseller, isn’t at all bad to look at, and is remarkably simple to operate.

Best combi boiler for a 3-bedroom house

Best Boiler:Viessmann Vitodens 050-W
Best Boiler Size: 30kW

German design at its best. The Vitodens 050-W 30kW is perfect for three-bedroom homes and not only more powerful than its competitors but officially more reliable too. 

Read the Vitodens 050-W Combi Boiler Review.

If you live in an average-sized home, see our guide on choosing the best boiler for a 3 bedroom house. 

Best combi boiler for a 4-bedroom house

Best Boiler: Viessmann Vitodens 050-W
Best Boiler Size: 35kW

Eternal reliability, award-winning and a 10-year parts and labour warranty – that’s basically like Helen Mirren personally looking after your home's heating requirements and keeping a close eye on your energy bills.

Best combi boiler for a 5+ bedroom house

Best Boiler: Viessmann Vitodens 100-W
Best Boiler Size: 35kW

The only other building in the world that harbours more of these boilers than Viessmann’s actual factory is Buckingham Palace, Her Majesty has at least 1 per every member of staff and three for every dog. In all seriousness though, it is genuinely the boiler of choice for the palace and rightly so. It’s a peerless and powerful boiler built entirely from premium components.

Do you live in a great, big house? Read our guide on the best boilers for large homes. 

Read the Vitodens 100-W Combi Boiler Review.

Want to have your combi boiler moved to a different location? Check out "cost of moving boiler" guide.

Best combi boiler by size (power output)

If you’re in the 99% of readers who have power-scrolled through this article picking up keywords like Good, Combi and Batman…

Then this quick overview of the best combi by size is the one for you:

Best small combi boilers:

#1: Viessmann Vitodens 100-W 26kW

#2: Baxi 600 – 24kW / 30kW

Best large combi boilers:

#1: Viessmann Vitodens 100-W 35kW

#2: Worcester CDi Classic 38kW

Best offensively large, powerful combi boilers:

#1: Worcester CDi Highflow 29kW / 30kW

#2: Viessmann 111-W 32kW

Want to know what kW you need for your home? Check out our "what size boiler do I need" guide.

Best combi boiler in terms of awards 

Who, What, Why, Where, When, Which?

Who is Which? anyway?

Which? is an independent consumer advice platform that offers UK homeowners and consumers impartial advice on an array of products and services. They are undeniably well-informed and absolutely love question marks.

Some special products, of high birth and royal blood, even manage to secure themselves a prestigious nod from the mighty Which – the Which? Best Buy Award, with Worcester Bosch having held that title for 14 consecutive years. 

You can check the latest deals on Worcester Bosch boilers here. 

They use their annual boiler survey to award the best boiler, which is based on feedback from thousands of UK installers and homeowners. 

Getting yourself a bargain boiler is one thing. But getting yourself a well-priced Which? Best Buy boiler is like dropping the bandit.

Best budget combi boilers 

Alpha E-Tec NX Combi Boiler 

Alpha's most popular combi boiler.

The Alpha E-Tec NX is the brand's best-selling combi boiler and offers a level of quality to rival premium manufacturers but at a budget-friendly price point. 

For example, they are built with a stainless-steel heat exchanger which is usually something you would only expect in a premium brand. 

Alpha offers a warranty of 7 years on their Alpha E Tec, but Heatable offers an exclusive 10-year warranty, which also matches some of the premium brands. 

Ideal for: Those looking for high quality and reliable boiler at an affordable price point. 

Interested in the Alpha E-Tec? Get a fixed price on a brand new model with gas safe installation as quick as tomorrow. 

Most efficient combi boilers 

All modern combi boilers use condensing technology and are considered A-rated and at least 90% efficient. 

According to the Energy Saving Trust by replacing your old G-rated non-condensing boiler with a modern A-rated condensing boiler you could save as much as £385 a year.

For example, the Viessmann 100-W is more than 90% efficient and A-rated, making it one of the most efficient combi boilers available. 

Get a Quote for a New Boiler Today 

If you’re aiming to get the best deal on a new boiler, consider getting a quote from us, here’s why:

• Gas Safe installation within 24 hours.

• Thousands of satisfied customers with an average score of 4.9 on Trustpilot, surpassing the market leader.

• Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.

• Price match guarantee: We will match any like-for-like cheaper quote.

• Flexible payment options, including interest-free finance.

• Up to 12-year guarantee on selected boilers.

• Fixed price guarantee: No hidden costs.

• Save your quote and decide later.

• Get an instant fixed price on a new boiler, here.

To learn more about boilers, visit our advice section, check out our YouTube channel, or read customer testimonials here.

Heat Happy.

*Hydrogen blend ready: most gas appliances, like boilers, can operate on a hydrogen and natural gas mix, with 20% hydrogen and 80% natural gas. So, if the government boosts "green gases" in the UK gas grid, you can trust their gas boilers will continue working without needing a complete switch to electric boilers in the future.