Small to medium sized homes with 3 bedrooms, around 15 radiators and 2 bathrooms are well suited to a 30kW combi boiler. If you’re looking for the best 30kW combi boilers then you’ll want to consider these 6 models:

1. Ariston Clas One
2. Baxi 830
3. Ideal Logic Max
4. Vaillant ecoTEC Pro
5. Viessmann 200-W
6. Worcester Greenstar 30i

In this article, we’ve compared these best 30kW combi boilers to help you when it comes to finding a new boiler for your home.

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Is a 30kW combi suitable for my home?

A combi or system boiler with an output rating of 28-34kW is widely recommended for small detached homes and medium-sized terraces with 2 bathrooms and around 15 radiators. So if you live in a home similar to this, then a 30kW combi boiler is likely to be a great fit for the heating and hot water demands of your home

While a system boiler will be able to deliver a higher flow of hot water to more than 1 tap simultaneously, they need a hot water cylinder. This will take up additional space, which makes combi boilers cost-effective space-savers.

A Gas Safe registered engineer will be able to make the best recommendation for the type of boiler and output rating that will be best suited to your home.

Best 30kW combi boilers

If a 30kW combi will suit the heating and hot water of demands of your home then you’re in luck because there’s a great range to choose from.

Best 30kW Combi Boilers	Seasonal Space Heating Efficiency	ErP Rating	Warranty
Ariston Alteas One Net	90.3%	A+*	12 years
Baxi 830	93%	A	10 years
Ideal Logic Max	94%	A	10 years
Vaillant ecoTEC Pro	Up to 94%	A	2 years
Viessmann 200-W	Up to 98%	A	3-5 years
Worcester Greenstar i	94%	A+**	7 years

*When used with the Cube RF modulating room sensor controls that come with the boiler
**When installed with the smart internet connected Bosch EasyControl

Ariston Alteas 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 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 include:

• 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 35 kW.

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 include:

• 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

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

• 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

Vaillant are a manufacturer well known for delivering efficient heating systems and their ecoTEC Pro 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.

• A premium stainless steel heat exchanger increases 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

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. Some key features of the Viessmann Vitodens 200-W 30kW include:

• 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 30i

Worcester is arguably the most well-known and trusted boiler manufacturer in the UK and their range of Greenstar boilers lead the way in terms of efficiency and performance. The Greenstar 30i has a number of features that make it well worth considering:

• Fitted with a low energy pump to reduce the amount of electricity being used
• Hot water flow rates of 12.3 litres per minute
• Condensate discharge that’s resilient to freezing in temperatures as low as -15°C
• A low energy pump helps to reduce the amount of electricity being used
• Boiler frost protection which will keep the Greenstar running throughout the winter

Other models in the range include the Greenstar 25i which has an output rating of 25 kW.

Worcester Bosch offers an extensive range of combi boilers so while we’ve picked out the Greenstar 30i they have a number of other 30kW combi boilers that you might want to consider too.

More Worcester 30kW Combi Boilers	Seasonal Space Heating Efficiency	ErP Rating	Warranty	Potential Cost
Greenstar 8000 Style	94%	A	10 years	£1,300
Greenstar 8000 Life	94%	A	10 years	£1,200
Worcester 2000	93%	A	5 years	£900

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30kW combi boiler prices

The best 30kW combi boilers will potentially cost around £960 to £1,565. This is before considering the installation which will typically be priced at between £500 – £1,000 depending on the complexity and rates charged by the installer.

Best 30kW Combi Boilers	Potential Cost (excluding installation)
Ariston Alteas One Net	£1,300
Baxi 830	£960
Ideal Logic Max	£1,000
Vaillant ecoTEC Pro	£1,150
Viessmann 200-W	£1,565
Worcester Greenstar 30i	£1,075

To get the most competitive price for the installation of your new combi boiler, we highly recommend comparing quotes from multiple heating engineers. And there’s no easier way to compare quotes than with Boiler Guide.

Simply take a few moments to complete our online form and you’ll get free quotes from up to 3 trusted tradespeople based in your local area.

Best 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 are LPG compatible. Find out which in the table below.

Best 30kW Combi Boilers	LPG Compatible?
Ariston Alteas One Net	Yes
Baxi 830	No
Ideal Logic Max	Yes
Vaillant ecoTEC Pro	No
Viessmann 200-W	Yes
Worcester Greenstar 30i	Yes

The alternative option 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 Utility UC120HEE	33 kW	89.1%	5 years	£1,990
Worcester Bosch Greenstar Heatslave II	32 kW	91%	2 years	£2,350

How do combi boilers work?

Combi boilers heat water for central heating and domestic hot water (DHW) on demand using water from the mains. After being heated, it is then delivered to taps and showers on demand without being stored in a hot water cylinder.

This makes them compact cost-effective units that won’t take up much space around the home. One of the reasons why combi boilers are the most popular choice of boiler in the UK.

Find out more about combi boilers:

• How do Combi Boilers Work?
• What is a Combi Boiler?

Free combi boiler installation quotes

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 pass through our online form and you’ll get free quotes from up to 3 heating engineers based in your area.

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