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Best 30kW Combi Boilers in 2024: Prices & Reviews in the UK

Becky Mckay
By: Becky Mckay
Updated: 7th January 2024

best 30kw combi boilers uk

To do that, you'll first need to know whether that 30kW output rating (which is a measure of the boiler's power) is for central heating or hot water. As combi boilers have a separate output rating for each one. And these ratings are rarely the same.

Here you’ll find a list of the best combi boilers with a 30kW output for central heating (CH) and the best for domestic hot water (DHW) – jump to the list you need:

Best 30kW combi boilers (DHW)
Best 30kW combi boilers (CH)

If you already have a good idea on what kind of boiler you would like, then you can already start reaching out to installers. But how do you find a qualified and reliable installer?

Finding an installer on your own can be tedious and take up hours of your time, as you’ll need to research and contact each one individually. This is even trickier if you’re not sure what qualifications to look out for when vetting heating engineers.

At Boiler Guide, we have a network of experienced Gas Safe registered engineers who can help you with installing your new boiler. Using our service is much quicker than trying to connect with heating engineers on your own and will also give you peace of mind that they have the correct qualifications.

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What is a 30kW combi boiler?

All types of boiler heat the home on demand but only a combi provides instant hot water.

That's because they don't store water in a cylinder – like system boilers and regular boilers (also known as conventional boilers). Instead, they heat water from the mains each time you turn on a hot tap.

For this reason, combi boilers have a central heating output rating as well as a domestic hot water output rating. Both will need to match the needs of your home.

Is a 30kW combi boiler right for my home?

A combi boiler with a DHW output of 30kW is great for homes with a bathroom and ensuite. Meanwhile, a CH output of 30kW suits homes with around 15 radiators.

Not sure if a 30kW combi is right for your home? Then contact a Gas Safe registered engineer to find out.

Best 30kW combi boiler: Domestic hot water

If you're looking for a combi boiler with a domestic hot water output of 30kW, you should consider one of these:

  • Ariston Clas One
  • Baxi 830
  • Ideal Logic Max
  • Vaillant ecoTEC Pro
  • Viessmann 200-W
  • Worcester Greenstar 8000 Style
Best 30kW combi boilers CH output DHW output Seasonal space heating efficiency Warranty
Ariston Alteas One Net 28 kW 30 kW 90.3% 12 years
Baxi 830 21.1 kW 30 kW 93% 10 years
Ideal Logic Max C30 24.2 kW 30.3 kW 94% 10 years
Vaillant ecoTEC Pro 25.7 kW 30 kW Up to 94% 2 years
Viessmann 200-W 25.4 kW 30.5 kW 94% Up to 10 years
Worcester Greenstar 8000 Style 30 kW 30.2 kW 94% Up to 12 years

Ariston Alteas One Net combi boiler 30kW

Ariston Clas One Net
The Ariston Alteas One Net is a highly efficient condensing combi boiler with a sleek black-coloured glass front, which gives it a very modern look and feel. The warranty period of 12 years is one of the most extensive you'll find on a combi boiler. And if you use the heating controls provided with your Ariston boiler, it will achieve an ErP A+ rating.

Benefits of the Alteas One Net

  • Quiet operation levels that are similar to a fridge freezer
  • Easy-to-use LCD display gives greater control
  • Fitted with an XtraTech stainless steel heat exchanger which boasts 142% wider waterways to increase its effectiveness and greatly reduce the risk of a blockage
  • The 'COMFORT' function ensures that the heat exchanger remains pre-heated to deliver instant hot water when you need it
  • Weighs only 35.3kg making it lightweight and simple to install
  • Additional space within the boiler makes installation, servicing and any repairs simple for engineers

The Alteas One Net range includes another combi boiler with an output rating of 35kW.

Baxi 830 combi boiler 30kW

Baxi 830
The Baxi 830 is part of the Baxi 800 range of boilers, which are compact, lightweight and fitted with brass hydraulics. It's potentially the most affordable of the best 30kW combi boilers but is still a high-quality heating system that's covered by a lengthy 10 year warranty.

Features of the Baxi 830

  • Fitted with an ADEY Micro2 magnetic system filter which protects the boiler and entire heating system
  • Able to fit within a standard kitchen cupboard
  • Low lift weight (29.2kg) makes for an easier installation
  • Flue options of up to 20 metres for a flexible installation
  • Control the boiler wherever you are using a smartphone or tablet

This range from Baxi also includes the 825 (25kW) and 836 (36kW) models.

Ideal Logic Max C30 combi boiler 30kW

Ideal Logic Max C30
Ideal is one of the most reputable boiler brands around and their Logic Max C30 is a highly efficient and effective home heating system. Their confidence in this unit is proven by an extensive 10-year warranty which can be extended to 12 years when installed by an Ideal Max accredited installer.

Features of the Ideal Logic Max

  • Easy to use thanks to a large backlit LCD digital display
  • Compact in size which means it can be hidden away in a standard cupboard
  • Fully-compatible with Ideal controls
  • Boiler frost protection to prevent the water in the boiler from freezing should the temperature drop below 5°C

If a heating engineer recommends a lower or higher output for the heating and hot water demands of your home, the Logic Max range also offers outputs of 24kW and 35kW.

Vaillant ecoTEC Pro combi boiler 30kW

Vaillant ecoTEC Pro
Vaillant is a manufacturer well known for delivering efficient heating systems and their ecoTEC Pro 30 boasts efficiency of up to 94%. Compared with other combi boilers, the 2 year warranty period of the ecoTEC Pro is relatively short but it can be extended to 7 years when the installation is registered through Vaillant Advance.

Features of the Vaillant ecoTEC Pro

  • A premium stainless steel heat exchanger increases boiler efficiency
  • Compact dimensions of 720 x 440 x 338mm (HxWxD) will save space
  • Awarded Quiet Mark accreditation thanks to low noise levels during operation
  • Delivers hot water at a rate of 12.3 litres per minute
  • The 'aquaCOMFORT' feature increases the speed of hot water delivery
  • Fitted with a low NOx burner and fan that are fully modulating to increase efficiency
  • Take control of the heating wherever you are using the vSMART app

Other outputs in the Vaillant ecoTEC Pro combi range include 24kW and 28kW models.

Viessmann 200-W combi boiler 30kW

Viessmann 200-W
With the ability to achieve efficiency ratings of up to 98%, the Viessmann 200-W is one of the most efficient combi boilers available on the market.

Viessmann 200-W features

  • Quiet during operation
  • Modulation range of 1:17 for increased efficiency
  • Fitted with a stainless steel Inox-Radial heat exchanger to increase efficiency
  • Control from your smartphone or tablet using the ViCare app
  • Option to extend the warranty period to 10 years

Output ratings of 26kW and 35kW are also available in this range of Viessmann boilers.

Worcester Greenstar 8000 Style combi boiler 30kW

Worcester Bosch Greenstar 8000 Style
Not many boilers are available in different colours but Greenstar 8000 Style boilers give you the choice of white or black. So you can make sure it suits your home.

Features of the Greenstar 8000 Style

  • Take your pick of a black or white unit
  • A modulation ratio of 1:10 means the boiler can greatly reduce the amount of energy it uses to help lower your bills
  • Lightweight to make installation easier, help to lower installation costs
  • Full-colour digital display with clear text
  • The standard 5 year guarantee can be extended to 12 years

As you can see, there are plenty of top-quality combi boilers to choose from. Of course when it comes to any purchase, we want to get the best value for our money. That’s why it’s crucial to compare installers, as well as the actual boilers, so you can avoid overpaying and poor service.

If you need a combi boiler with a domestic hot water output of 30kW and want to get the best price on your installation, we can help you. Click the button below and we’ll provide you with free quotes from up to 3 qualified heating engineers who can help you install your new 30kW boiler.

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Best 30kW combi boilers: Central heating

These combi boilers are a great option for a home with around 15 radiators.

Best 30kW combi boilers (CH) CH output DHW output Seasonal space heating efficiency Max warranty
Alpha E-TEC 29.7 kW 32 kW 93% 7 years
Baxi Duo-tec 30.3 kW 33 kW 93% 7 years
Vaillant ecoTEC Plus 838 30.1 kW 38.7 kW 94% 10 years
Worcester Bosch Greenstar 8000 Style 30 kW 30.2 kW 94% 12 years

Only the Worcester Bosch Greenstar 8000 Style features in both lists of the best 30kW combi boilers in 2024.

Alpha E-TEC

Alpha E-Tec
The Alpha E-Tec is one of the smallest combi boiler ever made by Alpha at 712mm x 440mm x 255mm, so it can be hidden away in a cupboard.

Features of the Alpha E-TEC

  • Increased efficiency thanks to a stainless steel heat exchanger
  • Delivers 14.1 litres of hot water to a tap in a minute
  • You'll be well covered by a warranty of 7 years

Baxi Duo-tec

Baxi Duo-Tec
Baxi are well-known for making efficient and reliable heating systems and the Duo-tec combi is no different.

Features of the Baxi Duo-tec

  • A strong flow rate of 13.5 litres per minute
  • Greater choice of where to fit the boiler thanks to a range of flue lengths
  • Lengthy warranty of up to 7 years
  • Designed for easy installation so the installer won't need to be in your home for long

Vaillant ecoTEC Plus 838

Vaillant ecoTEC Plus 838
The Vaillant ecoTEC Plus 838 has the highest DHW output of all the boilers in this article (38.7kW). So it can comfortably meet the hot water needs of a home with 2 bathrooms.

Features of the ecoTEC Plus 838

  • A very powerful DHW output of 38.7kW
  • Delivers a flow rate of 20 litres per minute
  • Low energy usage thanks to a modulation range of 1:6
  • Quiet Mark approved to show that it's near-silent as it heats the home
  • The warranty can be extended from the standard 5 years to 10 years

Worcester Bosch Greenstar 8000 Style combi boiler 30kW

Worcester Bosch Greenstar 8000 Style
The Worcester Greenstar 8000 Style is the only combi boiler to offer a 30kW output for both central heating and domestic hot water. Making it the ideal choice for homes with 2 bathrooms and around 15 radiators.

Features of the Greenstar 8000 Style

  • Take control of the heating and hot water with the Bosch EasyControl app
  • Pressure will remain strong thanks to the intelligent filling system
  • Energy consumption is kept to a minimum thanks to a modulation ratio of 1:10
  • You can extended the warranty to 12 years

If you’re looking for a combi boiler with a central heating output of 30kW, we can help you make an informed decision with our expertise and vetted network of heating engineers. This way, you can avoid being scammed and feel confident that you’re not overpaying for a subpar service..

Click the button below and we’ll put you in touch with up to 3 Gas Safe registered engineers who can help you install your new 30kW boiler.

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30kW combi boiler prices: Costs in 2024

The best 30kW combi boiler prices will be around £815 to £1,550.

This is before adding the installation cost which will typically be priced at between £500 – £1,000. But this completely depends on the ease of installation and rates charged by the installer. Which is why comparing quotes is always a good idea.

Best 30kW Combi Boilers (DHW) Potential Cost
Ariston Alteas One Net £1,300
Baxi 830 £955
Ideal Logic Max C30 £1,026
Vaillant ecoTEC Pro 30 £1,211
Viessmann 200-W £1,550
Worcester Bosch Greenstar 8000 Style £1,200
Best 30kW Combi Boilers (CH) Potential Cost
Alpha E-TEC £815
Baxi Duo-tec £898
Vaillant ecoTEC Plus 838 £1,408
Worcester Bosch Greenstar 8000 Style £1,300

30kW combi boiler price: running costs

When considering 30kW combi boiler prices, it’s crucial to take into account the future running costs alongside the upfront costs. The running costs of your boiler will depend on factors such as its efficiency rating and fuel type.

In Great Britain, electricity is significantly more expensive compared to gas and oil. You can find a breakdown of the fuel prices in Great Britain as of September 2023:

Fuel type Average price (pence/kWh)
Gas 8.0
Oil 9.0
LPG 8.7
Wood pellet 13.8
Electricity (standard rate) 30.0

As already mentioned, the 30kW combi boiler prices in the tables above are only estimates. To get an exact price, you need to receive quotes from heating engineers. We can help you with this.

Click the button below and you will receive up to 3 free quotes from qualified heating engineers in our network. You can then compare their offers and choose the best deal – this way you can feel assured that you’re not overpaying.

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Best 30kW combi boilers for off-grid homes

All of the best 30kW combi boilers we've highlighted above are fueled by natural gas which can't be installed into off-grid properties. Homes in this situation will need either an LPG or oil boiler, fuels that can be stored onsite.

Fortunately, the majority of the best 30kW combi boilers in 2024 are LPG compatible. Find out which in the table below.

Best 30kW Combi Boilers (DHW) LPG Compatible?
Ariston Alteas One Net Yes
Baxi 830 No
Ideal Logic Max C30 Yes
Vaillant ecoTEC Pro No
Viessmann 200-W Yes
Worcester Bosch Greenstar 8000 Style Yes
Best 30kW Combi Boilers (CH) LPG Compatible?
Alpha E-TEC Yes
Baxi Duo-tec No
Intergas Combi Compact Eco RF Yes
Vaillant ecoTEC Plus 838 No
Worcester Bosch Greenstar 8000 Style Yes

The alternative to LPG is oil. There aren't any oil combi boilers with an output rating of 30kW but Warmflow and Worcester Bosch have models that could still be suitable.

Oil Combi Boilers Output Rating Efficiency Warranty Potential Cost
Warmflow Agentis Internal Combi 33 kW AAA 5 years £2,470
Worcester Bosch Greenstar Heatslave II 32 kW 91% 2 years £2,350

Free combi boiler installation quotes

Researching different boiler types and models is already time-consuming enough without having to spend more of your free time researching installers on top of that. At Boiler Guide, we offer a free, non-binding service to take this task off your plate. So, you can spend your free time how you like and feel confident that your installer is qualified to do a good job.

If you're looking for a new combi boiler, we can connect you with Gas Safe registered engineers based in your area who are fully-qualified to carry out the installation. Simply click the button below, fill out our quick and easy form. Then you’ll get free boiler quotes from up to 3 heating engineers based in your area.

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FAQ

How many radiators can a 30kW boiler run?

How many radiators your 30kW boiler can run depends on the type of boiler it is. A 30kW combi boiler can run roughly between 10-15 radiators. A 30kW system or regular (conventional) boiler, on the other hand, is suitable for a home with 15-20 radiators.

How big a house will a 30kW boiler heat?

A 30kW boiler will generally heat a medium- to large-sized house. A medium- to large-sized house typically has 3-4 bedrooms with 2-3 bathrooms and 10+ radiators. It’s crucial to look up 30kW combi boiler reviews and talk to a professional heating engineer to ensure you’re getting the correct size of boiler for your home.

How much gas does a 30kW combi boiler use?

How much gas your 30kW combi boiler uses depends on the length of time it is running for. You can calculate your daily gas consumption (measured in kWh) with the calculation: boiler size (kW) x the number of hours used per day. For example, if you use your 30kW boiler for 5 hours per day, you will be using 150kWh of gas each day.

However, it’s important to also consider factors such as your boiler’s efficiency rating and how well your home is insulated when it comes to calculating your 30kW combi boiler running cost.

How much does it cost to run a 30kW boiler per hour?

Your 30kW combi boiler running cost will depend on a number of factors, including your boiler’s fuel type and efficiency rating. It will also depend on how well-insulated your home is. For example, from October 2023, you can expect gas to cost £0.07 per kWh (kilowatt-hour) in the UK. So, if your 30kW boiler uses 30kWh of gas, you will spend £2.10 per hour. However, as mentioned, there are other factors that may affect your total running costs.

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Becky Mckay

About the author

Becky Mckay

Becky has been a writer at Boiler Guide since 2021. Her vast boiler knowledge means she’s ready to help with any home heating query, big or small!

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