• home
  • Blog
  • Best combi boilers & boiler brands

Updated: April 6, 2024

What are the best combi boilers?

The best combi boilers brands are Baxi, Glow Worm, Ideal, Potterton, Vaillant, Viessmann and Worcester Bosch.

UK Combi boiler brands and combi boiler reviews:

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 went on to rate the most common brands of Combi boiler under the following categories:

  • Brand Overall score,
  • Reliability score,
  • Customer score,
  • Brand engineer score,
  • Typical price for a 30kW Combi boiler.

What is the cost for a combi boiler?

  • 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

According to the Which? article, 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.  The review took place in May-June 2021.

Brand Engineer Scores

A 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.

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

So now you can see the combi boiler scores via the article direct including the various prices.

It’s good to also consider what makes a good combi boiler?

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.

Good Combi Boiler Brands:

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

Who are the top boiler manufacturers?

As per the same Which? article which sites a 2021 boiler survey of 8,001 members of the public:

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

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

# Baxi boilers

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

Details: Its has lots of models in it range like; Assure, Duo-tec, Megaflow and Platinum combi boilers.  They all come in various sizes to suit almost any size and type of property.

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

# Glow-worm

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

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

# 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 like; Exclusive, Instinct, Esprit Eco and Logic+ ranges.

Boiler Prices: You can get a 30kW medium-sized Combi boiler from around £600, going up to £1,300.

# 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 bit it still owns the Titanium Combi boiler brand.

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

# Vaillant boilers:

Details: German manufacturer Vaillant is a large combi boiler manufacturer which has models like; ecoFIT and ecoTEC in its range of combi boilers.

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

# 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.

# Worcester-Bosch boilers

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

Boiler 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.

Best combi boilers & boiler brands

What to consider when buying a combi boiler?

  • 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.

Combi Boiler Guide

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?

In order to get the best combi boiler, it is crucial to choose a reliable brand that won’t break down.

  1. It’s also important to pick a combi boiler that’s the right size and fit for your home.
  2. And you need to select the right boiler for your budget*

*we can assist you with finance should this be required for 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
  • For 10-15 radiators you need a boiler between 28kW and 34kW
  • With 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.

Feel free to contact us to arrange this or proceed online to our online quote portal.

About Let’s Heat

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 or our different types of boilers articles for more info and please feel free to proceed with an online quote. Get quote!

We don’t just fit combi boilers!

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

Please find the 4 different boiler types that we work with:

  1. The Common, Heat Only Boiler
  2. A System Boiler
  3. Combi Boiler

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!

Best combi boilers & boiler brands

What are the energy regulations in the UK?

Over the last few years, the UK has passed several government guidelines for boiler replacement and energy efficiency, which now need to be adhered to for all boiler replacements, so please remember these because you need to ensure your new boiler meets the regulations:

  • If you have a gas boiler, it must have at least a 92% ErP efficiency regardless of boiler type.
  • A Combi boiler installation requires one energy-saving feature
  • You must have functioning time and temperature controls

Can I finance my new combi boiler?

Buying a new boiler and having a boiler installation or a heat pump, is an investment because it can be expensive initially. Especially paying for it all in one hit, which is why we provide some options.

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 but check that it is FCA-approved like ours.

Click the link to know more about our boiler finance plan.

We can also offer a number of split payment options for you to consider because this can be easier than dumping up your payment, all in one go.

Read about: best boiler for a large house

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.

So why Let’s Heat for your combi boiler replacement?

A. Let’s Heat Are Quality & Accredited Boiler Installers

Let’s Heat professional engineers and emergency plumbers provide a professional and reliable emergency plumbing and heating service.

Our Coverage

This service includes Boiler Installation and Heat Pump Installation, in Cardiff and the surrounding CF postcode areas of South Wales.

We also cover the rest of Wales and all of England (see below).

The 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 requirements no matter what time or day this is required!

Qualifications & Accreditations:

Our team of high-quality professional engineers has 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.


All of our staff at Let’s Heat are experts in their field and have gathered many years of experience, working on a wide selection and variety of emergency plumbing and heating solutions and services throughout Cardiff, the rest of Wales & the UK.

B. Because we care…

Are you still a little confused about where to start or who to use?

Our easy-to-use online questionnaire will guide you through everything that you, and we, need to know in order to ensure that you have the correct solution for your needs.

We will also ensure that you are completely satisfied with the solution offered prior to completing any works.

Why else?

  • Cover Cardiff and surrounding areas of South Wales
  • Reliable, professional, and trustworthy
  • High Trustpilot score of 4.9 out of 5.
  • Gas Safe Accredited (corgi registered),
  • Our prices are very competitive
  • Our Finance is FCA accredited
  • We ensure that your house is kept clean and tidy during any work
  • All workmen use floor protection on each job
  • We always make sure your rubbish is correctly disposed of
  • The Service comes with a 12-month snag guarantee
  • We travel anywhere throughout the UK

Get an Online Quote

You can research your boiler replacement requirements and choose your new boiler and the boiler installation online, without leaving the house…

If you need a new combi boiler or heat pump and installation, please do not hesitate to reach out to our award-winning heating engineers team because they have more information.

When you’re ready for a new boiler or heat pump then you can get everything, including the full boiler replacement from us here at Let’s Heat.

Can I get Next Day Service?

We replace & install boilers and heat pumps nationwide and include next-day installation (on orders placed before 12/2 pm in Spring/Summer or Autumn/Winter.

All staff are experienced and knowledgeable in all aspects of heating installation services and repair and maintenance, so if you have any further questions please feel free to contact us.

Alternatively please take a look at our FAQS or blog, should you have any other questions.

Get an online quote

Full range of heating & plumbing services provided by Let’s Heat:

  • Boiler Repairs & Installations
  • Boiler Supply & Fit
  • Financing Your Boiler
  • Emergency Boiler Repairs & Installations
  • Emergency Boiler Supply & Fit
  • Plumbing Repairs
  • Bathroom Plumbing
  • Kitchen Plumbing
  • Emergency Plumbing Repairs
  • Bathroom Plumbing in Emergencies
  • Emergency Kitchen Plumbing
  • General Plumbing Services
  • Emergency Plumbing Services
  • Emergency Gas & Heating Engineer

Areas covered by our Boiler Replacement Services:

The Let’s Heat engineers cover all of Wales & England


Let’s Heat provide Heat Pump installations throughout Wales, including areas like; South East Wales, South Wales, South West Wales, Mid Wales, East Wales, West Wales, and North Wales.

Welsh Cities:

This includes all of the Welsh cities like; Cardiff, Newport, Swansea, and all other towns and cities in Wales.


Let’s Heat provide Heat Pump installations  throughout England, including areas like; South West England, South East England, East Midlands, West Midlands, North West England, and North East England.

English Cities:

This includes all of the English cities like; 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.

Boiler installation

Any more questions?

If you have any further questions about Combi boilers, other Boilers, or anything else, please see our FAQ Page because you might find the answers there or on our News Blog.

Check out our Gas Safe Registration or if you would like to see our near 5 star Trustpilot rating please click the relevant link!


Is a combi boiler gas or electric?

An electric combi boiler does all the usual tasks of a gas combi boiler. But it would only use electricity to power your central heating and hot water. You can use an electric combi boiler for hot water only, but generally speaking, it will meet all of your heating needs.

Does a combi boiler need a water tank?

Combi boilers heat water directly from the mains when you turn on your tap. As a result, you won’t need a hot water storage cylinder or a cold water storage tank. Additionally, they are cost-effective and energy-efficient because water is heated instantly rather than being heated and then stored in a cylinder.

Are combi boilers good for showers?

To begin with, combi boilers are incompatible with boiler pumps, so power showers cannot be installed with a combi boiler system. Electric showers however, can improve the water pressure in a shower slightly. System boilers and regular boilers can be connected to power showers.

Can you run 2 showers off a combi boiler?

For homes where a higher demand of hot water is required, the higher the kw of the boiler, the better the flow rate of hot water would be. That being said, combi boilers do not work well with 2 showers running at the same time in the same property.

What temperature should I set my combi boiler to?

For a modern combi boiler, the radiator heating temperature ought to be set at or around 75 degrees celsius to get the best efficiency and performance.

How long does a combi boiler last?

A combi boiler should have a lifespan of between 10 and 15 years. However, boiler technology is always evolving, so the best way to make sure you have the most efficient and reliable combi boiler is to upgrade your heating system at least every 15 years.