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Best 30kW Combi Boilers to buy [Updated 2022]

best 30K Combi Boilers

5 Best 30kW boilers to buy for your home. What to get and what to avoid…

Best 30kW Combi Boilers to buy [Updated 2022] Compare Boiler Quotes

If you’re here, it’s likely that you already know you need a 30kw boiler for your home, but’s not until you start looking for a new boiler that you suddenly realise just how many there are to choose from.

There’s deciding which manufacturer, then which model, and then you need to make sure that it’s the right size to provide enough hot water and heating for your home.

Use this free quotation tool to find your perfect 30kW boiler – Click here

So, we’ve done the hard work for you. We’ve scoured the market, looked at all the options and decided on our top five 30kW combi boilers.

If you’re short of time and need to know right now which ones made it to our shortlist, here they are:

1. Worcester 4000 30kW

2. Viessmann 050-W 30kW

3. Worcester 2000 30kW

4. Viessmann 100-W 30kW

5. Ideal Logic C30 30kW

So, let’s now, first of all, find out if a 30kW boiler is the best choice for your home, and then we’ll take a look at our top five in more detail.

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Is a 30kW boiler best for your home?

Boiler size is measured by its output, so that’s in kilowatts (kW). Although every home has slightly different requirements, the more hot water and heating you need, the higher the kW will need to be in order to supply it.

Best 30kW Combi Boilers to buy [Updated 2022] Compare Boiler Quotes

Don’t be tempted to go for a boiler larger than you need. Although this used to be the recommendation, boiler efficiency is now so much improved that there’s no need to pay for a larger system than you actually need.

A 30kW combi boiler will be perfect for a home that has between 10 and 15 radiators. If you’re looking for a heat-only or system boiler, then 30kW is a good choice when there are between 15 to 20 radiators.

Use this free quotation tool to find your perfect 30kW boiler – Click here

Our top 5 and best 30kW combi boilers in order:

1.    Worcester 4000 30kW combi boiler

Worcester Bosch is one of the most respected and best boiler brands in the UK.

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They’re well known for the quality of their products which combine the latest technology with incredibly high levels of efficiency. The Worcester 4000 combi is no exception.

The Greenstar 4000 is a replacement for Worcester’s top-selling Greenstar i, and everything indicates that this will also become one of their most popular models.

Everyone wants the best combi boiler for their home so you will not go far wrong with the Worcester 4000.

Use this free quotation tool to find your perfect 30kW boiler – Click here

Key features of the Worcester Bosch 4000

Quick tap

Quick Tap is a great way of saving both energy and water. When you turn a hot water tap on, you then stand and wait for up to ten seconds before the water begins to get hot.

With Quick Tap, you simply turn the hot water tap on and then immediately back off again.

The boiler now knows that you need hot water, and so after waiting twenty seconds, turn on the tap, and you’ll be met with an immediate supply of hot water. 


High levels of efficiency

Worcester Bosch has pulled out all the stops to ensure that the Greenstar 4000 is one of the most environmentally friendly boilers currently available.

To achieve this, it has a modulation ability of 1:10. So for a 30kW boiler, it can drop down to the equivalent of a 3kW boiler when the heating demands are low.

Modulation has two big benefits. First of all, it saves energy, resulting in lower energy bills and then it also reduces wear and tear on the boiler, prolonging its working life.

Intelligent filling system

Your central heating system relies on the correct balance of air and water to operate efficiently. If the pressure is low, then this usually means that you have to attach a fillip loop and add water until the correct pressure is reached.

The intelligent filling system continually monitors the boiler pressure and reacts if the pressure is below what it should be. When the water level needs topping up, the internal filling valve is triggered to open and top up the water level.

Future proof boiler

The UK Government has committed to introducing a natural gas/hydrogen blend into the gas network by 2025. That means that it’s incredibly important to ensure that your new boiler can operate on this new mix of energy sources.

The Greenstar 4000, like all Worcester Bosch boilers, can already run on a 20% hydrogen blend without needing any alterations or additional technology, so your boiler replacement will stand the test of time.



Worcester Bosch offers a generous guarantee of up to ten years.

  • Standard guarantee – 7 years
  • Also fit a Greenstar System Filter – 8 years
  • Make an additional payment and fit a Greenstar System Filter – 10 years.
  • You can get 12-years warranty currently from Boiler Central.

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2.    Viessmann 050-W 30kW combi boiler

The 050-W combi boiler is Viessmann’s entry-level boiler; however, its functionality and design features enable it to compete with much more expensive models, so it’s no wonder that it’s one of Viessmann’s top-selling models.

Key features of the (new 2021 model) Viessmann 050-W 30kW

Inox-Radial stainless steel heat exchanger

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This Viessmann patented stainless-steel heat exchanger enables the Vitodens 050-W to be much more resistant to corrosion than boilers fitted with an aluminium heat exchanger.

Viessmann backs this up with a ten-year guarantee if leaks result from corrosion in the heat exchanger.

Compact design

Even though combi boilers do away with the need for water tanks and cylinders, space can still be tight in our homes. The Viessmann 050-W at just 700mm in height, 400mm in width, and 300mm in depth is designed to fit into a kitchen cupboard.

Choice of controls

While many people are moving to control their heating via an app on their phone, Viessmann recognises that’s not right for everyone.

So, the 050-W provides you with several different options. If you want to operate the system from the boiler, then that can be done through its control panel and touch buttons.

If you’d rather use smart technology, then that’s also an option because the 050-W is compatible with both Nest and Hive. And if you already have Alexa, then you can also control your heating using voice commands.

Weather compensation

With weather compensation installed, your boiler matches the heat being lost from your home with that being used.

That then creates a steady temperature rather than a cycle of rooms getting colder, which then triggers the heating to come on.

Now, the sensor that’s been installed on an outside wall lets the boiler know as soon as the temperature begins to drop so that adjustments can be made to keep the temperature at the perfect level.

Viessmann has estimated that using weather compensation can result in a 15% saving in energy bills without you needing to do a thing!


On the 050-W, Viessmann offers a guarantee of up to ten years, but we’ve found a way to increase that up to twelve years!

  • Standard guarantee – 3 years
  • When installed by a Viessmann Trained Installer – 7 years
  • When installed by a Viessmann Trained Installer and on payment of an additional premium – 10 years
  • When fitted with Boiler Central, then the warranty can go right up to 12 years

For more information on this model, take a look at our Viessmann 050 review.

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3.    Worcester 2000 30kW combi boiler

With the popularity of Worcester Bosch, it’s no surprise to see a second model on our top five list.

Super quiet operation

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The Greenstar 2000 combi boiler is Worcester Bosch’s entry-level boiler, and that makes it a popular choice for flats and apartments.

One of the key features that makes it a great choice for smaller living areas is that it’s so quiet. That means that it can be installed in the bedroom or living room without causing any disturbance.

In fact, the level of noise that the Worcester 2000 makes is so low that it’s been awarded a Quiet Mark certification.


Compatible with Bosch EasyControl

Taking control of our heating is incredibly easy with Bosch EasyControl. This wireless system allows you to change the temperature and set heating controls through an app on your mobile phone. 

That means that if you’re going to be home later than planned, you can easily change the time that the heating comes on; no more heating an empty house.

EasyControl also lets you quickly and easily monitor your energy use so that you can see just how much you’re saving.

High levels of efficiency

The Worcester 2000 has an efficiency level of 93%. So that means that it loses just 7% of the energy used when providing heating and hot water. That gives it an ErP A-rating for both heat and hot water.


Worcester Bosch offers a guarantee of up to ten years on the 2000 30kW boiler.

  • Standard guarantee – 5 years
  • When installed with a Greenstar System Filter – 6 years
  • When fitted with Boiler Central – 8 years

Use this free quotation tool to find your perfect 30kW boiler – Click here

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4. Viessmann 100-W 30kW combi boiler

When a boiler has managed to be awarded a Which? Best Buy several years running, so it’s definitely one that should be on everyone’s shortlist.

Key features

Integrated Wi-Fi

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When the 100 W was updated in early 2021, one of the key new features was the integrated Wi-Fi.

Not only does it allow homeowners greater flexibility in how they manage their heating, but it also allows remote access to a nominated heating engineer.

That means that if there is a fault, the engineer will automatically be alerted.  Then they’ll be able to log onto the boilers system to see exactly what’s causing the problem.

It could even mean that they can fix the problem without needing to carry out a home visit.

MatriX-Plus burner

We all want to reduce fuel consumption. Not only does it result in lower energy bills, but it also reduces emissions.

This new burner from Viessmann achieves both of those goals while carefully matching heat production with your needs.

Lambda Pro Plus combustion control

While you may have a continuous gas supply, its quality and operating conditions can fluctuate.

The Lambda Pro Plus combustion control ensures that no matter what’s happening with the gas supply, you’ll still have a reliable source of hot water and heating.  

The Lambda Pro Plus also reduces emissions so that the system needs cleaning less frequently.


Just as with other manufacturers, there are different levels of warranty available on Viessmann boilers. For the 100 W, that can be between five and twelve years of cover.

  • Standard warranty – 5 years
  • When installed by a Viessmann Trained Installer and when paying an additional premium – 12 years
  • When purchased through Boiler Central, a 12-year warranty saving you £500, which offsets from the new boiler cost you initially pay.

For more information have a look at our Viessmann 100 review.

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5. Ideal Logic C30 30kW combi boiler

Ideal is well known for its innovative technology, and so their Logic C30 has well and truly earned its place in our top five.

Key features

Built-in frost protection

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One of the features which we really like in the Ideal C30 is built-in frost protection. This means that when the weather turns colder, there’s no need to worry about problems with the boiler.

That’s because the C30 will automatically adjust its settings to ensure that the water in its system doesn’t freeze.

Energy efficiency

The C30 achieves a 94% efficiency rating, and that means less wasted energy and lower bills.

With an A rating for energy efficiency for water and heating, the C30 is a great option for both reliability and sustainability.


It’s not just us that rate the C30 so highly, it’s also won a Queen’s Award as well as two Good Housekeeping Awards. Then there’s the fact that it is also Energy Saving Trust endorsed.

This means that not only has it been externally assessed to ensure that it meets industry agreed energy performance criteria and UK regulatory requirements, but it also meets the energy efficiency standards set by the Energy Saving Trust.


Ideal is currently offering extended warranties, but this might change in the future, so we recommend getting a quote for a new boiler now so that you can check what’s currently available.

  • Standard warranty – 7 years
  • Heat exchanger when fitted with an Ideal System Filter – 10 years

Best 30kW combi boilers to buy: Final overview

So, there we have it, our top five 30kw picks. Each one is a great option for providing highly efficient and energy-saving hot water and heating.

The Worcester Bosch 4000 just pipped the others on our shortlist with its industry-leading levels of quality and efficiency combined with innovative technology such as its Quick Tap system.

Of course, we all have slightly different requirements, so we recommend getting a new boiler quote.

It takes two minutes and just needs you to enter a few details about your heating needs. Then you’ll be presented with your very own shortlist of perfect boilers.

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What our customers think

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Would recommend

Stressed when needed a new boiler but easy process with affordable finance. New boiler installed within a few days with option for next day.

Paul Jones 5 Star on Trustpilot

We were very impressed

On the day, they came on time. Lovely people, they kept everything clean. Explained everything to me. No mess, kept me informed.

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Great Experience

Great experience - quick to arrange, easy to work with the very responsive online team and all installed faster than expected.

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