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The Best System Boilers to Buy: Prices and Comparison

Nick Geary
By: Nick Geary
Updated: 10th February 2022

system boiler with unvented cylinder
If your home is too big for a combi boiler to be effective, and you'd rather not have a massive water tank in your attic, the best solution for your home is a system boiler – but which system boiler is best? That's a question you can answer with the help of this article.

If you're in a hurry to buy a new system boiler and want some comparison quotes for local installation, simply use this link to find professional heating engineers in your area.

The 5 best system boilers

When it comes to buying the best system boiler, there can be a lot of information to take in. That's why we've done the hard work for you by researching the best brands, models and key features of system boilers currently on the market.
To narrow our list down, we picked boilers from the top 5 most installed boiler brands; based on a recent Boiler Guide survey.

Most Popular Boiler Brands Survey

These 5 brands made up 92% of the boiler brands installed. That's why we have focused on one system boiler from each of these brands.

1. Worcester Bosch Greenstar 8000 Life

Worcester Bosch Greenstar 8000 Life system boiler

Price Range: £1,236 – £1,357 (excl. installation)
Sizes Available: 30kw, 35kw
Fuel Types: Gas, LPG

The Greenstar 8000 Life system boilers from Worcester Bosch are a great choice, whether you are connected to the national grid or not. This is because both models are LPG (Liquid Petroleum Gas) compatible. Each model is available in either a high gloss black or white finish too. This allows you to pick a boiler colour that compliments the décor of the room in which it's being installed.

To improve efficiency, an intelligent filling system constantly monitors the boiler's pressure and will automatically adjust it when needed.

These boilers have been designed with the future in mind and are capable of running on a 20% hydrogen blend without any need for modifications to the boiler. Find out more about the potential move to hydrogen fuelled boilers.

Outputs Efficiency Rating Typical Price (inc VAT) Warranty
30kw A Rated £1,317 5 – 12 Years*
35kw A Rated £1,446 5 – 12 Years*
* 12 years when fitted by Worcester Accredited Installer

Compare Worcester Bosch System Boilers

2. Ideal Logic Max

Ideal Logic Max system boiler

Price Range: £1,049 – £1,174 (excl. installation)
Sizes Available: 15kw, 18kw, 24.2kw, 30.3kw
Fuel Types: Gas

The Ideal Logic Max range of boilers are designed in the UK and come complete with a magnetic system filter which connects to your pipework to filter out any impurities in the water. This helps to protect the internal components and lengthens the life of the boiler.

They are also somewhat future proof as they are ready to run on a 20% hydrogen blend with no technical adjustments required.

Each system boiler in the Logic Max range has a scratch resistant casing to minimise day to day wear and tear of the unit. They also include built-in frost protection to allow for installation in a garage or another unheated room within a property. To ensure they are intuitive to use, each boiler in the Logic Max range boasts a large, easy to read, colour display.

Outputs Efficiency Rating Typical Price (inc VAT) Warranty
15kw A Rated £1,049 10 Years
18kw A Rated £1,089 10 Years
24.2kw A Rated £1,147 10 Years
30.3kw A Rated £1,174 10 Years

Compare Ideal System Boilers

3. Vaillant ecoTEC plus

Vaillant ecoTEC plus system boiler

Price Range: £902 – £1,537 (excl. installation)
Sizes Available: 12kw, 15kw, 18kw, 24kw, 30kw, 37kw
Fuel Types: Gas, LPG

The Vaillant ecoTEC plus range is one of the largest system boiler ranges available on the market. With 6 units ranging between outputs of 12kw and 37kw, it's highly likely there will be an option that's suited to the size of your home. Due to their flame lift detection system (which monitors the burner to ensure low combustion noise and optimal settings), these boilers are not only efficient, but exceptionally quiet too with the entire range being Quiet Mark approved.

Each of these system boilers is hand built in the UK and includes a function which allows it to drop to using 16% of its maximum power, which helps to save on fuel and money. They are compatible with a wide range of heating control options, from a simple boiler timer to the vSMART app.

If you are living off the grid and don't have access to gas, there are LPG (Liquid Petroleum Gas) compatible boilers in the range too (ecoTEC plus 618 and 630).

Outputs Efficiency Rating Typical Price (inc VAT) Warranty
12kw A Rated £902 5 – 10 Years*
15kw A Rated £971 5 – 10 Years*
18kw A Rated £1,098 5 – 10 Years*
24kw A Rated £1,227 5 – 10 Years*
30kw A Rated £1,363 5 – 10 Years*
37kw A Rated £1,537 5 – 10 Years*
* 10 years when installed by a Vaillant Advance Installer

Compare Vaillant System Boilers

4. Viessmann Vitodens 200-W

Viessmann Vitodens system boiler

Price Range: £1,344 – £1,650 (excl. installation)
Sizes Available: 11kw, 19kw, 25kw, 32kw
Fuel Types: Gas, LPG, Biogas

The system boilers in the Viessmann Vitodens 200-W range all come with a new environmentally responsible MatriX-Plus burner which adapts to the properties of different gas types automatically. This ensures that, whether you are using natural gas, LPG (Liquid Petroleum Gas) or biogas, the boiler will run as efficiently as possible. These boilers also utilise stainless steel Inox-Radial heat exchangers which can provide an extremely high efficiency rate of 98%.

The boilers in this range can connect to your wifi and be controlled by the ViCare app. Should a fault arise when a boiler is being controlled by the app, a Viessmann trained installer can be notified automatically.

All Viessmann Vitodens 200-W system boilers are hydrogen ready, and can run on a 20% hydrogen blend.

Outputs Efficiency Rating Typical Price (inc VAT) Warranty
11kw A Rated £1,344 3 – 10 Years*
19kw A Rated £1,500 3 – 10 Years*
24.2kw A Rated £1,550 3 – 10 Years*
30.3kw A Rated £1,650 3 – 10 Years*
* 10 years when installed by Viessmann Trained Installer and registered through the Viessmann Installer Portal

Compare Viessmann System Boilers

5. Baxi 600

Baxi 600 system boiler

Price Range: £877 – £1,011 (excl. installation)
Sizes Available: 15kw, 18kw, 24kw
Fuel Types: Gas, LPG

The Baxi 600 range is one of the most affordable system boiler ranges on the market. Built in the UK using brass components, these boilers come with an extensive range of flue options, providing flexibility on where they can be installed. They are also manufactured with a view to being used in the future, as all boilers in this range will run on a 20% hydrogen blend without any need for modifications, if the gas grid does move to hydrogen as a fuel source.

If you are not connected to the gas network, you could still use a Baxi system boiler as the Baxi 624 (24kw) model is fully compatible with LPG (Liquid Petroleum Gas).

Outputs Efficiency Rating Typical Price (inc VAT) Warranty
15kw A Rated £877 7 Years
18kw A Rated £889 7 Years
24kw A Rated £1,011 7 Years

Compare Baxi System Boilers

System boiler installation

To allow you to compare the price of different system boilers, we have deliberately provided figures that don't include the cost of installation. However, this is definitely something that you will need to consider.

System boilers need to be installed alongside a hot water storage tank (unvented cylinder). This will not only take up space in your property, but will also be an extra cost. If you're not sure what an unvented cylinder is or how it works, you can find out more in our 'what is an unvented cylinder?' article.

The cost of installing a system boiler can change dramatically, depending on how much work is required. A simple like for like installation will always be much cheaper than a complicated installation that requires a lot of extra work on the property. To ensure you get the best price, regardless of how much work is required, we recommend getting comparison quotes from professional heating engineers in your area. Fortunately, that's something you can do quickly and easily with our help. We'll provide you with FREE quotes from 3 engineers in your area. All you have to do is answer some simple questions after clicking the link below.



The best oil system boilers

At Boiler Guide we are well aware that gas boilers are not the only boilers on the market. That's why we also cover the best oil system boilers below. As oil boilers are less common and cannot be covered fully, without going into too much detail, we have listed the 5 best oil system boilers, and provided key information about each one.

1. Firebird Envirogreen Systempac

Firebird Envirogreen Systempac Oil Boiler
Price Range: £1,850 – £2,550
Sizes Available: 20kw, 26kw, 35kw, 44kw

  • For outdoor installation
  • Available in low NOx models which have lower carbon monoxide and nitrous oxide emissions
  • Full insulation and acoustic design for ultra-quiet operation
  • Built-in frost thermostat
  • Available in standard or slimline widths
  • Weatherproof PVC coated casing
  • A-rated for energy efficiency

Find out more about the Firebird Envirogreen Systempac

2. Grant Vortex Eco Utility

Grant Vortex Eco Utility oil boiler
Price range: £1,510 – £1,875
Sizes Available: 21kw, 26kw, 35kw

  • For freestanding indoor installation
  • Patented stainless steel heat exchanger
  • Quiet operation
  • Biofuel compatible
  • Easy front access for servicing and maintenance
  • A-rated for energy efficiency

Find out more about the Grant Vortex Eco Utility

3. Mistral Sealed System

Mistral Sealed System oil boiler
Price Range: £2,300 – £3,200
Sizes Available: 20kw, 26kw, 35kw, 41kw

  • Indoor and outdoor models available
  • Freestanding
  • Easy to install
  • Compact units with a max width of 410mm
  • Selection of flue options
  • A-rated for energy efficiency

Find out more about the Mistral Sealed System

4. Viessmann Vitorondens 200-T

Viessmann Vitorondens 200-T oil boiler
Price Range: £3,200 – £5,400
Sizes Available: 20kw, 24kw, 28kw, 35kw, 42kw, 53kw

  • Eutectoplex heating surface provides long service life
  • Corrosion-resistant, stainless steel Inox-Radial heat exchanger
  • JetFlow system for optimum heating water distribution
  • Compatible with smart devices via Vitoconnect
  • External silencer for quiet operation
  • A-rated for energy efficiency

Find out more about the Viessmann Vitorondens 200-T

5. Worcester Bosch Greenstar Danesmoor

Worcester Bosch Greenstar Danesmoor System Oil Boiler
Price Range: £1,738 – £2,297
Sizes Available: 18kw, 25kw, 32kw

  • Outdoor and indoor models available
  • Freestanding units
  • Solar compatible
  • Simple heating control
  • Option for 7 day plug-in programmer
  • A-rated for energy efficiency

Find out more about the Worcester Bosch Greenstar Danesmoor

Oil system boiler installation

How much the installation of an oil system boiler will cost is something that will vary greatly. There are many factors that could increase or decrease the price; from where you want the boiler to be installed to whether you already have a compatible hot water storage tank (unvented cylinder) installed.

To ensure you get the best possible price on your oil system boiler installation, we recommend getting comparison quotes. If you know which system boiler you want and are ready to get quotes from fully qualified heating engineers in your area, click the link below and we'll find up to 3 engineers who will provide you with their installation quotes.



Nick Geary

About the author

Nick Geary

Nick has a wide range of experience writing about conventional and renewable heating solutions, and is always increasing his knowledge by researching any new heating technologies on the horizon.

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