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Which is the Best 30kW System Boiler?

Becky Mckay
By: Becky Mckay
Updated: 6th July 2022

Best 30kW system boiler

The best 30kW system boilers are perfectly suited to properties with 2-3 bathrooms and around 15 radiators. When it comes to finding the right model, there's a range of reliable system boilers to choose from:

  • Ariston Clas System One
  • Biasi Advance Plus 7
  • Glow-worm Energy
  • Ideal Logic Max
  • Vaillant ecoTEC Plus 630
  • Worcester Bosch Greenstar 8000 Life
  • Worcester Bosch Greenstar 8000 Style

Is a 30kW system boiler suited to my home?

All boilers have an output rating which reveals the type of property it's best suited for installation. In the case of these best 30kW system boilers, they're ideal for medium-sized semi-detached properties with 3 bedrooms and 2-3 bathrooms.

System boilers are able to meet the higher hot water demands that comes with having multiple bathrooms thanks to being part of a heating system which includes a hot water cylinder. By storing hot water (unlike a combi which heats hot water on demand) a system boiler can deliver hot water to multiple taps at the same time without a drop in pressure.

The best way to find out which output rating is best suited to the heating and hot water demands of your home is by hiring a Gas Safe Registered engineer.

If a 30kW output rating isn't suited to your home then we've compared system boilers with output ratings from 24 kW up to 40 kW too:

Which is the best 30kW system boiler?

With 30kW system boilers being manufactured by many of the most reputable boiler brands, there’s a strong list of contenders that could be considered the best.

Best 30kW System Boiler Seasonal Space Heating Efficiency ErP Rating Warranty
Ariston Clas System One 90% A 8 years
Glow-worm Energy 89.3% A 7 years
Ideal Logic Max 93% A 10 years
Vaillant ecoTEC Plus 630 94% A 5 years
Worcester Bosch Greenstar 8000 Life 94% A 12 years
Worcester Bosch Greenstar 8000 Style 94% A 12 years

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Ariston Clas System One

Ariston boilers come with high-quality Italian design that comes with an 8 year warranty as standard thanks to a number of great features:

  • High efficiency pump to help lower your energy bills even further
  • An XtraTech heat exchanger with 142% wider waterways for increased reliability and performance
  • Runs quietly during operation (49-52dB)
  • A condensing surface makes the unit easier to clean and maintain which could help to save you money on any necessary future maintenance
  • Designed with user friendly controls

In addition to this 30 kW model, the Ariston Clas System One range also includes smaller outputs of 18 kW and 24 kW.

Glow-worm Energy

Glow-worm boilers are available at a relatively budget-friendly price but don't compromise on performance – as shown by the 7 year warranty.

  • A flexible choice of installation locations thanks to flue options on the top and rear of the unit
  • Aluminium heat exchanger to help increase efficiency and extend the life expectancy of the boiler
  • Compact dimensions mean that the unit can be installed within a standard kitchen cupboard
  • Fitted with a high efficiency modulating Grundfos pump which never uses more energy than is needed at any one time to lower energy costs

The 30kW model is the most powerful in the Glow-worm Energy range, with 12kW, 15kW, 18kW and 25kW units also available.

Ideal Logic Max

Ideal have built a reputation as one of the most reliable boiler manufacturers in the UK and are incredibly popular as a result.

  • Compact in size which allows for installation hidden away in a kitchen cupboard
  • Thanks to the compact size and low lift weight, installation is a relatively straightforward process which could help to limit the costs
  • Frost protection prevents the water from freezing during cold periods
  • Easy-to-use controls with a large digital display

Smaller outputs of 15 kW, 18 kW and 24 kW are available for properties with lower demands for heating and hot water.

Vaillant ecoTEC Plus 630

The Vaillant ecoTEC Plus 600 range of system boilers are highly efficient units housed within a unit that boasts modern stylish design.

  • Awarded Quiet Mark accreditation
  • To perform efficiently and keep your energy bills down ecoTEC Plus boilers can perform at 16% of their maximum power
  • Features a stainless steel heat exchanger for increased performance, efficiency and lifetime
  • Take control of the heating from your smartphone thanks to the vSmart app

Vaillant ecoTEC Plus 600 boilers are available in a wide range of output ratings to suit a number of different property types. As well as the 30 kW, there are 12 kW, 15 kW, 18 kW, 24 kW and 37 kW in the ecoTEC Plus 600 range too.

Worcester Bosch Greenstar 8000 Lifestyle

The Worcester Bosch Greenstar 8000 Lifestyle range of system boilers is split into two: Life boilers (30 - 50kw) and Style boilers (30 - 50 kW).

A key difference between these ranges is that Style boilers are available as black and white models, while Life units are white. Both Life and Style boilers share a number of industry-leading features:

  • Compatible with Bosch EasyControl allowing you to take control of the heating and hot water from your phone, wherever you are
  • 1:10 modulation to increase efficiency during operation

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How much do 30kW system boilers cost?

The wide range of 30kW system boilers that are available come with varying price tags. The more budget-friendly models are available from Biasi, Ariston and Glow-worm while the more premium models are manufactured by Ideal, Vaillant and Worcester Bosch.

Best 30kW System Boiler Potential Cost (before installation)
Ariston Clas System One £760
Glow-worm Energy £850
Ideal Logic Max £950
Vaillant ecoTEC Plus 630 £1,150
Worcester Bosch Greenstar 8000 Life £1,300 – £1,550
Worcester Bosch Greenstar 8000 Style £1,300 – £1,550

These costs don't include the hot water cylinder (which is essential part of a system boiler installation) or the installation costs.

A hot water cylinder stores hot water so that it’s ready to be sent to taps as and when needed. An unvented cylinder – which takes water directly from the mains – can cost from £450 to upwards of £1,000. Compare the Best Unvented Cylinders.

Installation of a system boiler typically costs £500-£1,000 but this will vary depending on the complexity of the installation and the rates charged by the installer. TO be confident that you're getting the most competitive price possible, we highly recommend comparing multiple quotes.

Take a few moments to complete our simple online form today and you'll get free quotes from up to 3 boiler installers for you to then compare.

System boiler benefits

A system boiler is a modern take on regular boilers that require less pipework (thanks to not needing any tanks in the loft) and have a faster response when you need heating or hot water. Some of the benefits of installing a system boiler include:

  • Store hot water in a cylinder which means that a strong supply of hot water can be delivered to more than one tap or shower at any one time
  • Modern alternative to a regular boiler that takes up less space and has a quicker response to calls for heating and hot water
  • Lower your energy bills even further with solar thermal panels – a renewable energy system that heats the water in a cylinder using solar energy

Best 30kW system boiler for off-grid properties

For properties that aren't connected to the gas grid, a natural gas boiler isn't an option. Instead, a liquefied petroleum gas (LPG) or oil boiler will be needed – these are both fuels that can be stored onsite.

Fortunately, the vast majority of the best 30kW system boilers are LPG compatible – great news for anyone living in an off-grid property.

Best 30kW System Boiler LPG Compatible?
Ariston Clas System One Yes
Glow-worm Energy No
Ideal Logic Max Yes
Vaillant ecoTEC Plus 630 Yes
Worcester Bosch Greenstar 8000 Life Yes
Worcester Bosch Greenstar 8000 Style Yes

Alternatively, an oil boiler can be installed. All of the boilers we've featured so far run on gas and not oil so below you'll find system oil boilers with outputs of 28-32kW.

Best 28-32kW System Oil Boilers Output Rating Seasonal Space Heating Efficiency ErP Rating Warranty
Navien LCB700 28kW 93% A 10 years
Viessmann Vitorondens 200-T 28kW 97% A 10 years
Worcester Bosch Greenstar Danesmoor 32 32kW 91% A 10 years

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A boiler replacement must be carried out by a fully qualified heating engineer but depending on the fuel, the installer will need a different certification.

Our list of the best 30kW system boilers are all gas, so if you're having one of them installed, you will need a Gas Safe registered engineer. An OFTEC technician is qualified to install oil boilers.

No matter the type of boiler you're planning to have installed, you can get free installation quotes right here at Boiler Guide. Take a few moments to complete our simple online form, letting us know about the work you need completing, and we'll match you with up to 3 local heating engineers. Each of these installers will provide a free quote for you to compare and be confident that you're getting the most competitive price possible.

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Becky Mckay

About the author

Becky Mckay

Becky is one of our home heating and renewable energy experts and has a wealth of experience writing about the world of heating.

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