What are the top UK combi boilers?

The top UK combi boilers are Alpha, Bosch, Baxi, Vaillant and Viessmann. You can check our website to know more about the best brands.

Top UK Combi Boilers
Top UK Combi Boilers 1

Top UK Combi Boilers

Welcome to the top UK combi boilers page.

On our website you’ll find reviews on the top UK combi boiler brands and models.

According to UK consumer brand Which, “if you want to buy the best combi boiler, you will  need to make sure it’s the correct size for your home and from a reliable brand.”

The Which article then goes on to rate the Most common brands of Combi boiler under the following categories:

Brand Overall score, Reliability score, Brand customer score, Brand engineer overall score, & Typical price for a 30kW Combi boiler.

For all score please see the full which article by clicking the link!

The Typical prices for the top UK combi boilers and boiler brands were listed in the article as;

Baxi £880 – £1,000

Glow Worm £700 – £990

Ideal £590 – £1,270

Potterton £650 – £1,350

Vaillant £1,160 – £1,410

Viessmann £780 – £1,280

Worcester Bosch £800 – £2,460

The which article states that the Reliability and brand customer score was based on responses from 8,001 members of the public who’ve bought a combi boiler in the last six years, that took place in May-June 2021.

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Engineers Score

The Brand engineer score was based on responses from 153 Which, Trusted Trader heating engineers in June 2021. 

The typical price range for the which assessment was based on the low and high price ranges for a standard 30kW combi boiler, across the combi boiler brand’s full range.

A 30kW boiler is suitable for most medium-sized homes.

The combi boiler prices do not include the boiler installation costs.

Read more about the combi boiler assessment by consumer magazine which at: https://www.which.co.uk/reviews/boilers/article/boiler-brand-guides/best-combi-boiler-brands-a1cCp5J6LCFu – Which?

So now you can see the combi boiler scores via the article direct and the various prices, it good to also consider what makes a good combi boiler?

According to the article, a good combi boiler will deliver plenty of hot water for your showers, baths and sinks, and will keep your radiators piping hot throughout the coldest of winters.

The article also covers the brands that make the most reliable combi boilers, according to the Trusted Trader Heating Engineers that were questioned.  

What are the main UK brands that make combi boilers?

There are 17 gas and oil boiler brands that are all producing combi boilers. 

Please find some details and pricing for the top 7 combi boiler brands:

Combi Boiler Brand: Baxi

Brand: Baxi is one of the biggest combi boiler manufacturers in the UK.

Details: Its range of Assure, Duo-tec, Megaflow and Platinum combi boilers come in various sizes to suit almost any size and type of home.

Price – They typically cost between £880 – £1,000 for a 30kW medium-sized combi boiler, although it has models starting from around £550.

Combi Boiler Brand: Glow-worm

Details: Glow-Worm has several ranges of combi boilers including Energy, Essential, Betacom, Easicom and Ultimate.

Price: Prices starting from around £560, with a medium-sized combi boiler usually being between £700 – £990.

Combi Boiler Brand: Ideal boilers

Details: Originally called the National Radiator Company, Hull-based Ideal has been around for 100 years. It has several ranges of combi boilers including Exclusive, Instinct, Esprit Eco and Logic+ ranges. 

Prices: You can get a 30kW medium-sized Combi boiler from around £590, going up to £1,270. 

Combi Boiler Brand: Potterton boilers

Details: Potterton is part of Baxi, which is in turn part of the BDR Therma Group. As such, several of Potteron’s ranges – such as its Assure range – have been absorbed under the Baxi name. It still owns the Titanium Combi boiler brand.

Price: Prices for the Titanium start at £800 for the 28kW size.

Combi Boiler Brand: Vaillant boilers

Details: German manufacturer Vaillant is a large combi boiler manufacturer which has the ecoFIT and ecoTEC range of combi boilers.

Price: These Combi boilers typically start between £1,160 – £1,410 for a medium-sized boiler of 30kW.

Combi Boiler Brand: Viessmann boilers

Details: Viessmann is a German boiler brand making waves in the UK boiler scene. Its Vitodens combi boiler lines have been updated in 2021.

Price: The Viessmann Boilers cost between £780 –  £1,280 for a mid-sized 30kW boiler, and come in a large range of sizes for the requirements of any home.

Combi Boiler Brand: Worcester Bosch boilers

Details: German manufacturer Worcester Bosch is one of the biggest combi boiler manufacturers in the UK. 

Price: The Greenstar combi boiler range starts at around £800 and goes up to around £2,500, depending on the size and the hot water flow that you need for your home.

Other things to consider?

  • Combi boilers are less suitable for homes with multiple bathrooms.
  • A faulty combi boiler will fail early and is likely to result in regular costly repairs.
  • On average, it costs almost £200 for a boiler repair so this can soon add up, making any cheaper boiler purchase more expensive than a more expensive but more reliable boiler, in the long run.(Which? survey, 2021).
  • It pays to invest in a boiler that will last. 
  • Size matters.  An oversized combi boiler will lead to you spending more on your heating and hot water than you need to, and an undersized one will deliver a disappointing flow of hot water to your taps and radiators.

Please read our guide on the  different types of boiler to see which type will best suit your property and your requirements.

So, What makes a good combi boiler?

  1. In order to get the best combi boiler, it is crucial to choose a reliable brand that won’t break down.
  2. It’s also important to pick a combi boiler that’s the right size and fit for your home. 
  3. And you need to select the right boiler for your budget*

*we can assist you with finance should this be required fir your new boiler purchase and installation.

How to pick the right size combi boiler for you property?

  • The simplest way to estimate the size of boiler you might need is to count the number of radiators you have.
  • If you have Fewer than 10 radiators you require a boiler under 27kW
  • When you have 10-15 radiators you need a boiler between 28kW and 34kW
  • Where you have more than 15 radiators you need a boiler with over 34kW

This is a rough guide. A fully trained heating engineer will be able to more accurately size your boiler after a full heat loss survey of your home.

Here at Let’s Heat we can use our vast experience to guide you through the correct boiler and boiler installation for your requirements.

Please feel free to see our boiler installation guide (link) or feel free to proceed with an online quote.

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We don’t just fit combi boilers!

In addition to combi boiler installation we also fit other boiler types:

  1. The Common, Heat Only Boiler
  2. A System Boiler
  3. The Combi Boiler
  4. The new Heat Pump!

The boiler installation & repair team are all fully qualified to the highest standards and take pride in producing exemplary work standards which include completing all boiler installation requirement no matter what time or day this is required!

Our team of high quality professional engineers have an extremely high 4.9 out of 5, Trustpilot score given by our previous happy customers and we are fully accredited by Gas Safe and Corgi registered, as well as FCA approved for all of our financial transactions.

The full range of heating & plumbing services provided by Let’s Heat are as follows:

Can I finance my new system boiler?

Buying a new boiler and having a boiler installation or a heat pump, is an investment. However it can be expensive, especially paying for it all in one hit.

If you haven’t got the money on hand for the boiler and installation services that you require, you can get the job done on a finance package that is FCA-approved.


FCA-Accredited Finance

We can also offer a number of split payment options for you to consider.

Boiler Replacement Payment Options

For new boiler installation, you can pay by card, pay zero deposit, and pay monthly over 2 to 10-years or take our a finance package.

Areas covered by our Boiler Engineers:

The Let’s Heat boiler engineers cover all of Great Britain including Wales, England, & Scotland


Let’s Heat provide Boiler Installantion throughout Wales, including South East Wales, South Wales, South West Wales, Mid Wales, East Wales, West Wales and North Wales.

This includes the cities of Cardiff, Newport, Swansea and all other towns and cities in Wales


Let’s Heat provide Boiler Installantion throughout England, including South West England, South East England, East Midlands, West Midlands, North West England, and  North East England.

This includes the cities of London, Reading, Southampton, Portsmouth, Bristol, Exeter, Plymouth, Gloucester, Swindon, Oxford, Leicester, Nottingham, Derby, Birmingham, Worcester, Wolverhampton, Walsall, Liverpool, Manchester, Leeds, York, Sheffield, Newcastle, Sunderland and Middlesbrough etc.

Have any further questions, please see our FAQ Page . 


Top UK combi boilers FAQs

  1. Are combi boilers cheaper to run?

    The main reason that most people switch from conventional to combi boilers is energy efficiency. You can save up to 40 percent on your energy bill if you replace your 10 to 15 years old boiler with an A-rated combi boiler.

  2. What’s the average cost of a new combi boiler?

    The average combi boiler cost is £1,800.

  3. How long should a Worcester Bosch combi boiler last?

    Worcester Bosch boilers tend to last between 12-15 years. However, in some cases, Bosch boilers can last over 22 years.

  4. Do combi boilers need a water tank?

    Combi boilers heat water directly from the mains when you turn on a tap, so you don’t need a hot water storage cylinder or a cold water storage tank in the roof space.

  5. Is it worth changing to a combi boiler?

    Replacing a 12-15 year older boiler with a new A-rated condensing combi boiler can save you up to 40% on your energy bills.