System Boiler Guide | We Compare Prices on 64 Boiler Models

Quick Guide Summary

What is a system boiler? Who offers the best system boiler prices in 2019?

System boilers are usually found in modern homes with multiple bathrooms. A system boiler works with an unvented hot water tank. Unlike a 'heat only' boiler the main system components are integral to the boiler. This provides for a more comprehensive boiler warranty from the manufacturer. Prices range from around £580 for an entry-level boiler to nearly £1,600 for a large, premium range model. The best system boiler for your circumstances will be based on your property size and your budget. In this guide we compare prices, sizes, efficiencies and warranties on 64 models of system boiler from nine leading manufacturers, including Worcester Bosch, Baxi, Ideal and Vaillant, to find the best system boiler for you. Once you have reviewed individual boiler prices, why not try our bespoke Boiler Quote Calculator for a full installation cost.

Overview of System Boilers

What is a System Boiler?

A system boiler provides heating and works with a steel cylinder to provide hot water. System boilers are usually found in larger homes with multiple bathrooms

Find your Best System Boiler

Use the tables below to find your best boiler based on price, efficiency and warranty length. For example, similar priced boilers offer 2 and 5 year warranties; it's easy to see which one is better value!

Found your boiler? What's next?

Get an estimate of installation cost with our Boiler Quote Calculator. Are you looking for flexible ways to pay for a new boiler? Read our comprehensive guide: Ways to Pay for Your New Boiler.

HOW TO USE THIS GUIDE

Guide to using the boiler tables

Find your property size

Find your best boiler according to budget

What is a System boiler?

System boilers work with a steel unvented hot water tank. They are usually found in larger properties with multiple bathrooms as they can supply good hot water flow rates simultaniously to two or more outlets (e.g. two showers). Unlike heat only boilers, all of the components that would usually be found external to the boiler (pumps, valves etc) are inside a system boiler. This means more of the heating system is covered by the boiler manufacturer's warranty. System boilers require good incoming water pressure and good internal flow rates to operate at their stated capacity. If you currently have a heat only boiler on a gravity system you will need to check your water flow rates to make sure a system boiler will work.

When is a system boiler right for my home?

System boilers suit properties with multiple bathrooms, particularly where they are in use simultaneously, for example people showering in the morning. System boilers provide good hot water flow rates from a high performance cylinder. Many new build properties have system boilers with unvented hot water systems, replacing your boiler will be a straight swap. For those considering installing a system boiler in place of their combi boiler, this is worth while when you are extending and adding bathrooms. You will need to find a spot for the hot water tank and preferrably close to the bathrooms. For those with a conventional heat only boiler, you will need to change the boiler and the copper cylinder.

Find your best system boiler

Use the tables below to find your best sysem boier. The tables are arranged so that you can easily find your property size and then find who offers the best boiler package for your budget. The tables show boiler performance alongside warranty period and price so you can find the best value boiler. Most boiler manufacturers produce one or two models of system boiler with outputs between 12kW and 40kW. At the smaller end, the price difference between the budget and premium models is quite small. However the disparity grows signficiantly for the larger models.

Best Buys and Best Performance

We have identified ‘best buys’ in each size group. These reflect an all-round great package. We have also highlighted best performance boilers, which are not necessarily the cheapest but offer great efficiencies and warranties.

Guide to using the boiler tables

In the example table below, it is easy to see that the Vaillant ecoTEC plus at £772 is great value with a 7-10 year guarantee, compared the next cheapest and next most expensive, which only offer a 2 year warranty.

1-2 bed flat   Price Standard warranty Free extended warranty Central heating output Efficiency
Glow Worm Energy System 12 £712.00 2 2 12 89%
Vaillant ecoTEC plus system

12 £772.00 5 7-10 12 89%
Potterton Promax System 12 £794.00 2 2 12 89%

Find your property size and open up the table to find your best system boiler.

1-2 Bed Flats

With all the efficiencies and outputs about the same, the choice really comes down to warranty length. The Vaillant is by far the best buy with a great extended warranty and the second cheapest in the group!

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1-2 bed flat   Price Standard warranty Free extended warranty Central heating output Efficiency
Glow Worm Energy System 12 £712.00 2 2 12 89%
Vaillant ecoTEC plus system

12 £772.00 5 7-10 12 89%
Potterton Promax System 12 £794.00 2 2 12 89%
Vaillant ecoFIT pure system 12 £812.00 2 7-10 12 89%
Worcester Bosch Greenstar System i

12 £879.00 7 8 12 94%
Baxi Ecoblue System 12 £901.00 7 7 13 89%

2 bed houses

The two most expensive boilers are the most efficient - amazing work by Worcester Bosch and Ideal, however the best buy still goes to Vaillant for a great price and guarantee period on the boiler

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2 bed room house   Price Standard warranty Free extended warranty Central heating output Efficiency
Glow Worm Energy System 15 £731.00 2 2 15 89%
Ideal Logic System 15 £741.00 2 2 15 89%
Potterton Promax System 15 £808.00 2 2 15 89%
Ideal Logic + System 15 £809.00 7 7 15 89%
Vaillant ecoTEC plus system

15 £858.00 5 7-10 15 89%
Vaillant ecoFIT pure system 15 £875.00 2 7-10 15 89%
Baxi Ecoblue System 15 £923.00 7 7 17 89%
Worcester Bosch Greenstar System i

15 £926.00 7 8 15 94%
Ideal Vogue System 15 £944.00 8 10 15 93%

3 bed houses

Here we see Potterton and Ferroli enter the group offering two incredible cheap boiler models and the Ferroli comes with a 5 year warranty! Both the Vaillant Ecofit Pure and Ideal Logic+ are great mid range packages. Worcester Bosch still offers the best efficiencies in the pack.

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3 bedroom house   Price Standard warranty Free extended warranty Central heating output Efficiency
Potterton Gold System 18 £566.00 2 2 18 88%
Ferroli Modena HE 18S 18 £575.00 5 5 17 89
Glow Worm Energy System 18 £757.00 2 2 18 89
Ideal Logic System 18 £810.00 2 2 18 89%
Potterton Promax System 18 £825.00 2 2 18 89%
Ideal Logic + System 18 £841.00 7 7 18 89%
Vaillant ecoFIT pure system

18 £931.00 2 7-10 18 89%
Vaillant ecoTEC plus system 18 £954.00 5 7-10 18 89%
Baxi Ecoblue System 18 £962.00 7 7 20 89%
Worcester Bosch Greenstar System i 18i £974.00 7 8 18 94%
Viessmann 100-W System 19 £1,032.00 5 5 19 90
Worcester Bosch Greenstar System i

21 £1,014.00 7 8 21 94%
Ideal Vogue System 18 £1,015.00 8 10 18 93%
Viessmann 200-W System 19 £1,296.00 5 5 19 90

4 bed houses

By far the biggest group! Prices at the top end are almost three times of the entry level boilers. The Ideal Logic + System and Vaillant ecoFIT pure are great buys for larger properties.

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4 bed house   Price Standard warranty Free extended warranty Central heating output Efficiency
Potterton Gold System 21 £589.00 2 2 24 88%
Ferroli Modena HE 25S 25 £588.00 5 5 25 89
Main System Eco Elite 24 £617.00 3 3 26 92
Glow Worm Energy System 25 £809.00 2 2 25 89
Ideal Logic System 24 £844.00 2 2 24 89%
Potterton Promax System 24 £863.00 2 2 25 89%
Ideal Logic + System 24 £872.00 7 7 24 89%
Worcester Bosch Greenstar System i

24i £1,035.00 7 8 24 94%
Worcester Bosch Greenstar System i 27i £1,042.00 7 8 27 92%
Baxi Ecoblue System 24 £1,053.00 7 7 27 89%
Viessmann 100-W System 26 £1,068.00 5 5 26 90
Ideal Vogue System 26 £1,169.00 8 10 26 93%
Vaillant ecoFIT pure system

25 £1,100.00 2 7-10 25 89%
Vaillant ecoTEC plus system 24 £1,137.00 5 7-10 24 89%
Viessmann 200-W System 26 £1,410.00 5 5 26 90
Vaillant ecoTEC exclusive 27 £1,438.00 5 7-10 27 90%

5 bed houses

The lower end boilers are plentiful but only the Ferroli offers a decent 5 year warranty. The best efficiency in this group goes to the Ideal Vogue - well done! Worcester are not far behind on 92%. The best all round value goes to the Ideal Logic+ - a great price and package.

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5 bed house   Price Standard warranty Free extended warranty Central heating output Efficiency
Potterton Gold System 24 £609.00 2 2 28 88%
Main System Eco Elite 28 £680.00 3 3 29 92
Ferroli Modena HE 32S 32 £669.00 5 5 31 89
Glow Worm Energy System 30 £833.00 2 2 30 89
Ideal Logic System 30 £877.00 2 2 30 89%

Ideal Logic + System

30 £902.00 7 7 30 89%
Baxi Ecoblue System 28 £1,087.00 7 7 31 89%
Viessmann 100-W System 30 £1,100.00 5 5 30 90
Worcester Bosch Greenstar System i 30i £1,112.00 7 8 30 92%
Worcester Bosch Greenstar System Cdi 30 £1,132.00 7 10 30 92%
Vaillant ecoTEC plus system 30 £1,173.00 5 7-10 30 89%
Vaillant ecoFIT pure system 30 £1,207.00 2 7-10 30 89%
Ideal Vogue System

32 £1,256.00 8 10 32 93%
Viessmann 200-W System 30 £1,519.00 5 5 30 90

5+ bed houses

The best buy and best performance goes to Worcester Bosch! If you need maximum output from a domestic system boiler then the Vaillant ecoTEC plus gives you an extra 2kW over the next biggest

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Larger properties   Price Standard warranty Free extended warranty Central heating output Efficiency
Potterton Promax System 32 £948.00 2 2 34 89%
Baxi Ecoblue System 30 £1,137.00 7 7 35 89%
Worcester Bosch Greenstar System CDI

35 £1,245.00 7 10 34 92%
Vaillant ecoTEC plus system 37 £1,312.00 5 7-10 37 89%
Viessmann 100-W System 35 £1,511.00 5 5 35 90
Viessmann 200-W System 35 £1,571.00 5 5 35 90

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