Best Combi Boiler Models 2023 Re November 12, 2021

Best Combi Boiler Models 2023

Boiler in kitchen

It’s that time of year when temperatures drop and enquiries start to rise, so if you’re in the market for a new boiler, we take a look at the best combination boiler models out there now!

But first, if you’d like to know about the best combi boiler brands on the market, take a look at our blog. Don’t forget to check out the ‘best new boilers to buy in 2021’, where we talk about the best combi, system and conventional boilers.

Have I got a combi boiler?

A combination boiler is the most common boiler type. In fact, over half of all boiler installs in the UK are combis. The combination boiler is named for its ability to provide a combination of both heat and hot water for your home.

Combi boilers are connected directly to the mains water supply coming into your home; they heat this water directly, eliminating the need for a separate water tank (as with a system or regular boiler). This saves a great deal of space, especially in flats and smaller homes where space is limited.

Combination boilers are more economical as they only heat the water that you require. Many people that have older boilers (like a back boiler) switch over to a combi boiler when they purchase a new one.

How does a combi boiler work?

In simple terms, the water is supplied directly from the mains, a gas burner is ignited when the tap is turned on, the heat exchanger transfers the energy to the water which heats it up, ready for you to use.

If you like to learn about the process in-depth, check out our blog on ‘how do combi boilers work’.

Combi boiler pros and cons

  • More efficient. By replacing your boiler with a newer combi boiler, you can save up to £300 a year on your energy bills. Don’t forget to treat yourself!
  • No storage tanks in the loft or airing cupboard which means it takes up less space
  • Combi boilers are cheaper to install than system and conventional boilers.
  • Easier to find replacement parts.
  • Enjoy mains pressure showers without the need to install a shower pump
  • With combi boilers, you are less likely to face issues like air locks or low pressure because the hot water is taken directly from the water mains.
  • Combi boilers are easier to service. That’s why our trusted engineers love them!
  • May not be able to produce enough hot water for multiple bathrooms in use at the same time.
  • Not all combi’s are compatible with solar energy.
  • Combi boilers have no backup immersion heaters to heat the hot water if your boiler breaks down.
  • You can’t have a power shower with a combi boiler. The water pressure is set at the water mains.

Best budget-friendly combi boiler 2022

There are always a lot of worthy competitors for the best budget boiler crown. There are a lot of boilers competing in the budget range that are reliable and affordable.

The best budget-friendly combi boiler 2022 is the Worcester Bosch Greenstar 2000.

Worcester Bosch is one of the best boiler brands on the market. They are the “Apple of the heating industry”. Known for their reliable boilers, outstanding build quality, sleek designs and long warranties.

Worcester Bosch currently holds the Royal Warrant to supply heating to the Royal Family and has won the Which? Best Buy Award for their range of boilers for the last ten years.

This prestigious award recognises the companies and individuals that consistently get it right for their customers. To break it down, the Which? Best Buy Award is judged on reliability, build quality, recommendation, and customer score. Think of it as the BRIT Awards of the heating industry!

Worcester Bosch has built an enviable reputation for customer aftercare, which is reflected in their 4.6/5 Trustpilot score. Customers are delighted with their boilers and customer care.

The Worcester Bosch 2000 series is a new addition to the Worcester Bosch family. It is a budget-friendly boiler range that combines sleek exterior designs with a powerful and reliable interior and not to mention excellent aftercare. It looks like the Worcester Bosch 8000 Life boiler but it’s a lot cheaper.

The Worcester Bosch 2000 comes in two sizes; 25kW and 30kW. The 25kW model is perfect for small to medium-sized homes, such as flats with one bathroom.

On the other hand, the 30kW model is more powerful, it can cope with a higher demand for hot water. This makes it ideal for medium-sized homes with 2 bathrooms.

WB 2000

Greenstar 2000 key features:

  • Bosch engineered quality at an affordable price. The total cost of buying and installing the 2000 boiler is between (£1750 – £1850 including VAT) – incredible value for money!
  • The perfect size to fit in small places such as kitchen cupboards.
  • It is the quietest Worcester Bosch combi boiler (43dB), now you can enjoy your work-from-home midday naps! 
  • Features Worcester Bosch innovative Quick Tap water-saving feature, which is activated with a quick opening and closing of a hot water tap. This helps to reduce water wastage in your home.
  • Peace of mind with a 10-year guarantee on the primary heat exchanger.
  • ErP rating 93%: A-rated – This means that 93p in every £1 you spend on using your boiler is paying for the energy that is keeping you warm.
  • Dimensions: 700mm x 300mm x 400mm.

If you’d like to get an instant fixed price quote on a new boiler suitable for your home, then take our survey now, it only takes a couple of minutes and you’ll have an idea of how much a new boiler will cost you.

Best premium combi boiler 2022

You’ll be delighted to hear that the winner for the ‘best premium boiler in 2022’ was unanimous. Despite there being a few decent boiler brands at the higher end of the market the decision was an easy one.

For 2022 our best premium combi boiler is the Worcester Bosch Style 8000, retaining its crown from last year.

Whilst looks aren’t everything, this boiler is the best looking of the bunch, so if your boiler is in a visible area then this big iPad-looking boiler is the one for you. Described by Worcester as the ‘Beautiful Beast’ it certainly lives up to its name. It’s by far the best-looking boiler out there and it’s the most powerful wall-hung boiler on the market, meaning there’s no need to hide it in a kitchen cupboard!

It has all the same great features as the Life range and it’s available in black or white. Engineers like it because it’s easy to fit, customers like it because it’s powerful and it looks good and we like it because of all the previous reasons and despite it being fairly early in its lifespan, it’s been a reliable boiler so far and Worcester boilers, in general, are the most reliable.

WB Style black 30kw

Additional benefits include:

  • Improved LCD display for ease of use
  • Easy integration with smart controls
  • Very quiet boiler
  • Award-winning customer service
  • Established brand leaders
  • 10-year guarantee (when purchased through WarmZilla)

Honourable mention goes to the Vaillant EcoTEC Plus combi boiler; a solid, reliable boiler without the flair of the Worcester Style boiler but a worthy runner up nonetheless. Vaillant have scooped the Which? Best Buy for 2021, always a good sign.

Best energy-efficient combi boiler 2022

The Energy Saving Trust said:

Heating and hot water accounts for over half of what you spend in a year on energy bills, so an efficient boiler makes a big difference.”

The boiler energy efficiency depends on a number of factors such as whether your boiler is a condensing or non-condensing unit, the age of your boiler, whether your boiler’s kW size is compatible with your homes needs, how many people are using the heating system at once, and plenty of other factors.

The best energy-efficient boiler on the market in 2022 is the Worcester Bosch Greenstar 4000.

Once again, Worcester Bosch manufactured a one-of-a-kind boiler that you can rely on to reduce your energy bills.

With an 84% Which? Brand Score and 94% efficiency rating (A-ErP Rating), the Worcester Bosch Greenstar 4000 is guaranteed to be the winner!

The Greenstar 4000 is perfect for small to medium-sized homes with one bathroom. It features a modern new design, an easy to use full-colour text display and it’s quiet too.

The Greenstar 4000 has a wide power range (25kW and 30kW) to meet all of your heating and hot water needs, whilst doing so efficiently.

In efforts to become more planet-friendly, the original polystyrene packaging used to package Worcester Bosch boilers has been replaced with recyclable cardboard. They have also ensured that all plastic packaging has been replaced with compostable bags which can be used in your garden or as a food waste bin. Although their packaging has been changed, their delivery still remains 5* by undergoing intense transport tests to make sure that your boiler is still protected and the new packaging is robust and keeps your boiler safe.

Based on the design of the famous, best-selling boiler on the market, the Worcester Bosch Greenstar i, Worcester Bosch have created a new and improved version, raising the bar with ease and speed of installation, commissioning, and servicing. The exterior of the 4000 series is very similar to that of the Worcester Bosch 8000 Life and Style boiler range, but it is significantly cheaper. This means you are getting all the great features and benefits of the Worcester Bosch Greenstar i, but with a little added spice!

Additionally, Worcester Bosch’s entire gas boiler range is able to run on a 20% hydrogen blend – so you can be confident it will run on mains gas for its lifetime. If you’d like to know more about hydrogen boilers, take a look at our blog.


Greenstar 4000 key features:

  • A wide power range helps to reduce gas consumption and lower energy bills.
  • Innovative ‘Quick Tap’ water-saving function helps you reduce water waste.
  • The modern new design comes with an easy to use Full-text colour display LED screen.
  • Operates extremely well in low water pressure areas, ensuring powerful and warm showers.
  • One of the quietest combi boilers available (45dB).
  • Features wireless connectivity with the Bosch EasyControl.
  • Reminder settings, fault history and drain-down function.
  • Easy access to drain valve and pressure gauge.
  • 100% planet-friendly packaging.
  • Simple Switch option.
  • Instantaneous hot water, always available.
  • Suitable for small to medium homes.
  • ErP rating 94%: A-rated.
  • Dimensions: 724mm x 400mm x 310mm.

A special mention goes to the Viessmann Vitodens 100-W combi gas boiler; an efficient and reliable boiler with an ErP rating of 94% (A-rated) and 81% Which? Brand score. Truly, a great runner up.

If you would like to know what kWs mean when it comes to your boiler, have a look at this guide.

Best combi boiler for shower pressure 2022

Fun fact about showers – “7% of people openly admit to not bathing at all. Be that a shower or a bath!

Pretty gross! But for the rest of us in the 93%, when you’ve had a long day at work and you want to come home and relax, a lot of us will jump into a hot bath or long shower, get out of our work clothes, and into our comfy PJs. However, sometimes, our relaxation time can be ruined when we experience issues with our water pressure or water temperature. This is why it’s so important that your boiler and water system work together in harmony.

Your water pressure can depend on several different factors such as the height of the reservoir or water tower above your property. If your home is on a hill, for example, you probably won’t get the same pressure as the people at the bottom. The number of people using the mains water pipe at one time will also affect the pressure. At busier times of the day, such as when you’re getting ready for work or when the kids are getting ready for school, you’re bound to experience weaker water pressure.

If you think there may be an issue with the water pressure coming into your home, it’s always best to get an expert’s opinion.

The best combi boiler for showers with the highest flow rate (litres per minute = 20.3) is the Worcester Greenstar 8000 Lifestyle 50kW.

The Greenstar 8000 Lifestyle range comes in 2 models: the Greenstar 8000 Life and the Greenstar 8000 Style.

Its quiet operation and innovative new features really portray a modern-day appliance. This, together with its beautiful aesthetics really make for a game-changing boiler.

WB 8000

Greenstar 8000 Life Key Features

  • Weighs less than the famous CDi Classic.
  • Installation, servicing and maintenance made easier.
  • Wireless connectivity with the Bosch EasyControl.
  • Same pipe connections, flue and fixing points as the CDi Classic enabling an easy swap.
  • Greenstar 8000 Life 50kW flow rate is 20.3 litres per minute – expect a great water pressure for showers!
  • 10-year guarantee (when purchased through WarmZilla).
  • ErP rating 94%: A-rated.
  • Dimensions: 780mm x 440mm x 365mm.

The Worcester Bosch Life also boasts new technology to ensure your system pressure is kept at its optimum level. This brand-new optional intelligent filling system monitors the boiler pressure and will automatically adjust it if necessary, removing the need to manually top up the boiler pressure. This ensures that the boiler is kept operating at its best.

Greenstar 8000 Style Key Features

  • Wireless connectivity with the Bosch EasyControl
  • Stunning design-led aesthetics
  • Precision engineering and industry-leading heating and hot water performance
  • Full-colour text display for simple diagnostics
  • Innovative boiler control display codes
  • Choose from 2 stunning high gloss colours – Black or White
  • Greenstar 8000 Style 50kW flow rate is 20.3 litres per minute
  • 10-year guarantee (when purchased through WarmZilla).
  • ErP rating 94%: A-rated.
  • Dimensions: 780mm x 440mm x 365mm.

Like the Life model, the Worcester Bosch Style also features the brand new optional intelligent filling system. The sleek full text and colour display makes navigating through the boiler’s on-screen menu as simple as possible. The settings can be effortlessly adjusted to provide optimum heating and hot water comfort.

This new range of boilers has been designed and produced as a direct result of installer feedback Worcester has received in past years. It takes the place of the ever-popular CDi Classic range and improves on its features while keeping that famous Worcester Bosch engine.

You can take an in-depth look at the Greenstar 8000 technical data here.

It’s worth mentioning that you should also check the type of shower you have and understand how it affects the water flow. As always, we got a guide for that!

Best combi boiler for flats 2022

As a rule of thumb, you should ensure that your heating system is suitable for your needs and the size of your home. If the boiler is too powerful for your home, you could end up forking out a load on your energy bills. On the contrary, a heating system that isn’t powerful could leave you without the warmth you need.

The best combi boiler for small flats/apartments is the Worcester Bosch Greenstar 25i.

The Greenstar i range was awarded the Which? Best Buys for all gas boilers in 2019 and 2020.  Being a proud Royal Warrant holder, the Greenstar i model was so successful that even the Royal Family has approved it. This was thanks to its perfect design for small to medium-sized homes with one to two bathrooms and up to three bedrooms – or even a Palace or two (apparently)! It was also ranked as one of the engineers’ favourites.


Greenstar 25i Key Features:

  • Low lift weight.
  • Single panel front for ease of removal.
  • The fan can be removed with just one screw and the expansion tank is now inside the boiler.
  • Large siphon inside – eliminates the risk of a freezing condensate pipe.
  • Clear text description for quick boiler diagnostics.
  • Simple weather compensation option.
  • Simple boiler controls with a clear information display.
  • ErP rating 93%: A-rated.
  • 10-year manufacturer’s warranty.
  • Dimensions: 710mm x 400mm x 330mm.

The Worcester Greenstar 25i is a high-performance but affordable combi gas boiler, one of the most popular boilers in the industry.

A hat-tip goes to the Ideal Logic Plus 24kw combi boiler; it’s a great runner up to the Worcester Bosch Greenstar 25i with an energy-efficiency rating of 94% and a 7-year manufacturer’s warranty. It certainly is a reliable boiler.

Why not get an instant fixed price quote on a new boiler now?

Best combi boiler for large homes 2022

We always say that the larger the house, the more powerful boiler you’ll need. We advise getting a system or regular boiler if your house is relatively large as both regular and system boilers store hot water in a cylinder. Larger homes could benefit from having a hot water cylinder if you have multiple bathrooms.

You can, in some cases, get away with an extremely powerful combi boiler if you have 1-2 bathrooms alongside the 5 bedrooms.

The best combi boiler for large homes is Viessmann Vitodens 200-W 35kW Combi Gas Boiler.

Viessmann Vitodens 200-W 35kW combi gas boiler is a powerful beast with a 35kW and A-ErP rating. It offers great efficiency, low emissions and simple operation. This model is a hydrogen ready boiler (H2 20% blend).

Vitodens 200-W 35kW key features

  • Vitotronic 100 is an optional constant temperature controller.
  • Quiet operations.
  • A swanky 7” colour touchscreen for maximum control and comfort in your home.
  • Integrated WiFi – it can be used with the ViCare app.
  • Built-in frost protection.
  • Stainless steel heat exchanger.
  • New environmentally friendly MatriX-Plus burner.
  • Easy to use controls.
  • ErP rating 94%: A-rated.
  • 10-year manufacturer’s warranty.
  • Dimensions: 700mm x 450mm x 360mm.

If you would like to compare the Viessmann Vitodens combi boiler with a couple of boilers, check out our boiler comparison tool.

Best combi boiler for underfloor heating 2022

The good news is that if you already have a combi boiler, you can still have underfloor heating installed. But it is slightly tricky, as you may require to carry out some adjustments.

If both your underfloor heating and radiators run off the same boiler, a qualified heating engineer (who is also specialised in underground heating) will have to install a two-port valve to protect the boiler from overheating.

The best combi boiler for underfloor heating is the Worcester Bosch Lifestyle 8000.


Worcester Bosch Life 8000 key benefits

  • More power – outputs up to 50kW for combi and regular.
  • Easier installation, servicing and maintenance.
  • Robust and simple to fit.
  • Reduced lift weight compared to the CDi Classic.
  • A new clean, modern design.
  • Full wireless connectivity with the Bosch EasyControl.
  • Same pipe connections, flue and fixing points for ‘simple switch’ with CDi Classic.

Worcester Bosch Style 8000 key benefits

All the benefits of Life, plus:

  • Stunning, design-led product aesthetics for contemporary homes.
  • A high-quality blend of precision engineering and class-leading heating and hot water performance.
  • Full-colour text display for simple diagnostics.
  • Innovative and intuitive boiler control display.

Why should you buy a new boiler from WarmZilla?

When you purchase a new or replacement boiler with us, your boiler package will also include;

  • Your chosen boiler, along with the necessary flue kit needed for your central heating system
  • Installation by a qualified Gas Safe Engineer 
  • Removal of your old boiler and parts
  • A FREE system cleanse of your central heating system
  • Chemical Inhibitor for added protection for your new boiler
  • 10-years guarantee, which will be registered by WarmZilla after installation
  • A FREE magnetic system filter for ongoing protection
  • The Neomitis RF Digital Wireless Room Thermostat

We hope that’s given you an overview of the top combis out there- so whatever you decide, you can stay warm and cosy this winter! Plus, if you’re looking to save money on your next boiler, why not get a free instant boiler quote now?

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