Gas system boilers, like heat only boilers, provide heat to radiators and stored hot water cylinders. System boilers are used for both high pressure unvented systems as well as gravity fed systems (with a cold water tank in the loft). System boilers differ from heat only boilers in that they have additional components, such as a water pump, built into the unit rather than being provided separately. As a result they tend to be slightly higher in price but on new installations this is more than offset by ease of installation and not having to buy additional components.
Below we list the popular system boiler options by power output in kW and then brand. Note that the prices are for the boiler only and do not include the flue. They are also typical prices and do not reflect any price promotions with a specific plumbers merchant or retailer. On occasions, manufacturers offer promotional packages which include the flue.
See also prices for: Heat Only Boilers and Combi Boilers.
If you want an indication of what you may pay for a boiler replacement including installation then use our replacement boiler cost online calculator. You can then compare any quotations from installers with this guideline estimate.
| Power Output | Product | Typical price inc VAT | Warranty Period Years * | Technical Details |
|---|---|---|---|---|
| 9kW | Worcester Bosch Greenstar 9i System | £971.60 | 5 | View |
| 12kW | Glow-worm Energy 12kW system | £795.91 | 7 | View |
| 12kW | Potterton Promax 12 plus system | £814.59 | 1 | View |
| 12kW | Vaillant ecoFIT pure 612 system | £881.23 | 2 | View |
| 12kW | Vaillant ecoTEC plus 612 system | £936.44 | 5 | View |
| 12kW | Worcester Bosch Greenstar 12i System | £936.10 | 5 | View |
| 15kW | Baxi Megaflo System 15 | £900.79 | 7 | View |
| 15kW | Glow-worm Energy 15kW system | £816.34 | 7 | View |
| 15kW | Ideal Vogue Gen2 System S15 | £996.36 | 8 | View |
| 15kW | Ideal Vogue Max System 15 | £993.65 | 10 | View |
| 15kW | Ideal Logic Max System S15 | £965.61 | 10 | View |
| 15kW | Ideal Logic+ Plus System S15 | £857.91 | 7 | View |
| 15kW | Potterton Promax 15 plus system | £829.10 | 1 | View |
| 15kW | Vaillant ecoFIT pure 615 system | £943.73 | 2 | View |
| 15kW | Vaillant ecoTEC plus 615 system | £997.91 | 5 | View |
| 15kW | Worcester Bosch Greenstar 15i System | £987.16 | 5 | View |
| 18kW | Baxi Megaflo System 18 | £929.29 | 7 | View |
| 18kW | Glow-worm Energy 18kW system | £851.21 | 7 | View |
| 18kW | Ideal Logic Max System S18 | £1,037.50 | 10 | View |
| 18kW | Ideal Vogue Max System 18 | £1,070.83 | 10 | View |
| 18kW | Ideal Logic+ Plus System S18 | £898.31 | 7 | View |
| 18kW | Ideal Vogue Gen2 System S18 | £1,077.36 | 8 | View |
| 18kW | Potterton Gold 18 System | £613.18 | 2 | View |
| 18kW | Potterton Promax 18 plus system | £846.63 | 1 | View |
| 18kW | Vaillant ecoTEC plus 618 system | £1,103.10 | 5 | View |
| 18kW | Vaillant ecoFIT pure 618 system | £1,019.79 | 2 | View |
| 18kW | Worcester Bosch Greenstar 18i System | £1,046.63 | 5 | View |
| 21kW | Worcester Bosch Greenstar 21i System | £1,094.94 | 5 | View |
| 24kW | Baxi Megaflo System 24 | £1,019.34 | 7 | View |
| 24kW | Ideal Logic+ Plus System S24 | £926.38 | 7 | View |
| 24kW | Ideal Logic Max System S24 | £1,036.49 | 10 | View |
| 24kW | Potterton Promax 24 plus system | £885.35 | 1 | View |
| 24kW | Potterton Gold 24 System | £638.08 | 2 | View |
| 24kW | Vaillant ecoTEC plus 624 system | £1,158.60 | 5 | View |
| 24kW | Worcester Bosch Greenstar 24i System | £1,101.71 | 5 | View |
| 25kW | Glow-worm Energy 25kW system | £907.60 | 7 | View |
| 25kW | Glow-worm Ultimate 3 25kW system | £767.50 | 5 | View |
| 25kW | Vaillant ecoFIT pure 625 system | £1,164.56 | 2 | View |
| 26kW | Ideal Vogue Max System 26 | £1,091.66 | 10 | View |
| 26kW | Ideal Vogue Gen2 System S26 | £1,218.41 | 8 | View |
| 27kW | Vaillant ecoTEC exclusive 627 system boiler | £1,478.90 | 5 | View |
| 27kW | Worcester Bosch Greenstar 27i System | £1,104.98 | 5 | View |
| 28kW | Baxi Megaflo System 28 | £1,053.10 | 7 | View |
| 28kW | Potterton Gold 28 System | £659.75 | 2 | View |
| 30kW | Glow-worm Energy 30kW system | £936.54 | 7 | View |
| 30kW | Ideal Logic+ Plus System S30 | £966.84 | 7 | View |
| 30kW | Ideal Logic Max System S30 | £1,071.86 | 10 | View |
| 30kW | Vaillant ecoFIT pure 630 system | £1,263.54 | 2 | View |
| 30kW | Vaillant ecoTEC plus 630 system | £1,347.91 | 5 | View |
| 30kW | Worcester Bosch Greenstar 30i System | £1,152.55 | 5 | View |
| 30kW | Worcester Bosch Greenstar 30CDi Classic System | £1,204.66 | 5 | View |
| 32kW | Baxi Megaflo System 32 | £1,078.60 | 7 | View |
| 32kW | Ideal Vogue Gen2 System S32 | £1,305.91 | 8 | View |
| 32kW | Potterton Promax 32 plus system | £972.41 | 1 | View |
| 35kW | Worcester Bosch Greenstar 35CDi Classic System | £1,344.44 | 5 | View |
| 37kW | Vaillant ecoTEC plus 637 system | £1,499.98 | 5 | View |
| 50kW | Worcester Bosch GB162 50kW | £2,057.85 | 2 | View |
| 65kW | Worcester Bosch GB162 65kW | £2,532.60 | 2 | View |
Typically new boiler prices range from close to 500 all the way to 2,500, so it’s important to get all the facts before you decide to buy a replacement boiler.