Which Is The Best Gas Boiler?

which gas boiler is best?

Buying a gas boiler is a big decision; there are so many things to consider. So, we thought we’d make life a little easier for you and present what we believe to be the best gas boilers UK manufacturers are currently offering.

If you’re wondering which is the best type of gas boiler, well there’s something for everyone from combi boilers through to system and conventional so no matter how big or small your home is, we have an excellent suggestion for you. We’ll also look at new boiler cost.

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Gas Combination Boilers

Greenstar 8000 Combi from Worcester Bosch

This is a replacement boiler which has been designed for ease of use. It has a clear display screen making it easy to get the system working for you, and it’s combined with the Bosch EasyControl app, meaning that you can control heating and hot water from anywhere. Worcester Bosch has complete confidence in their system with a warranty of up to twelve years.

This model is available in five different power outputs starting at 30kW and going up to 50kW. We have lots more information on the Worcester Bosch range for you here.

Vitodens 050-W from Viessmann

The Vitodens 050-W is one of the smallest boilers in its class and measures just 702mm in height. It’ also one of the best combi boilers. This is a low-price boiler which is perfect for smaller homes with up to three bedrooms. The 050-W is available in two power outputs, 29 and 35kW and with its very quiet operation, it’s perfect for fitting in the living areas of the home.

A weather compensated mode and a frost stat are already integrated into the Vitodens 050-W. All it needs is the optional outside temperature sensor for the boiler to adjust for the weather conditions. For more information check out our ultimate review of the 050-W

ecoTEC Pro from Vaillant

This hand-built combi boiler should be on your shortlist if you have a small to medium home and you’re looking for a solution which offers precision heating. Available in three power outputs, 24, 28 and 30kW and a flow rate of up to 12.3 litres per min providing instant hot water.

The ecoTEC pro achieves an efficiency of 89% which gives it an ‘A’ ErP rating. Vaillant offer quite a low two years guarantee as standard,  but this can go right up to 7 or 10 years when fitted by a Vaillant Advance installer.

Energy from Glow-Worm

This ErP A rated combi is available in three power outputs, 25, 30 and 35kW with each one achieving an efficiency level of 89%. This is a compact unit from Glow-Worm and it tidily fits into kitchen cupboards. The 25 and 30kW models are also Quiet Mark approved so you won’t be disturbed while the boiler is running.

The Energy combi comes with a seven-year warranty straight out of the box, but this can be extended to a fantastic 15 years when using an approved installer.

E-Tec Plus from Alpha

The E-Tec Plus is the new combi from Alpha and has been developed from their popular E-Tec range of boilers. The E-Tec Plus comes with a  stainless-steel heat exchanger, and zinc plated expansion vessel which resists corrosion and reduces the need for maintenance.

Available in 28 and 33kW models Alpha provides a ‘straight out of the box’ 10-year warranty.

The 600 Combi from Baxi

The Baxi 600 is built in the UK and comes in three power outputs, 24, 30 and 36kW. Designed for quick and easy installation, the 600 weighs from just 27kg and is fitted with a simple hanging bracket. The 600 comes with the EasyFill functionality, making it easy to top up the pressure without needing an engineer’s assistance.

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Gas System Boilers

Greenstar i System from Worcester-Bosch

Worcester-Bosch’s most popular system boiler is the ideal choice for a small to medium home. Available in five different power outputs from 9-24kW you’re able to get the perfect power needed to meet your heating and hot water needs. The Greenstar i has a low energy pump which reduces power usage and can even be combined with Greenskies solar panels for the ultimate low energy use. This really is one of the best system boilers

For protection during colder months, the Greenstar i has a Condensesure style siphon built into the boiler, eliminating risks associated with frost.

Vitoden 200-W from Viessmann

When a manufacturer promises greater efficiency, lower emissions and simple operation there’s not too much more that you can ask for! Well, that’s precisely what Viessmann offer with the Vitoden 200-W. These types of gas condensing boiler is designed for larger homes.

The 200-W has an integrated Wi-Fi interface that can be controlled via the ViCare app on your smartphone or tablet. You can even set-up it up so that your installer is informed at the hint of a problem so that you can avoid breakdowns.

Gas Regular Boilers

Greenstar Ri from Worcester Bosch

This larger output boiler is available in 27 and 30kW versions. It’s still compact though and small enough to fit into a kitchen cupboard. If you have a medium or large sized home, then this could be a good option.

This is a straightforward boiler to use with a simple control knob though you can install the EasyControl adaptor to enable you to set the boiler through the Bosch Easy control app. The Greenstar Ri comes with a 10-year warranty when fitted by a Worcester accredited engineer.

Eco-Fit Pro from Vaillant

This lightweight and compact regular boiler provides excellent performance and low energy consumption. The Eco-Fit Pro is available in six different heating outputs from 12 to 35kW and can reduce that output to 20% when less heat is needed.

Compatible with Vaillant’s vSMART app this boiler can be controlled via the internet, making it easy to make those small adjustments that can make a significant difference to your fuel bills.

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Best New Gas Boilers Prices

New replacement boiler costs are a big part of the decision making when it comes to buying a new boiler. Here is our latest price guide without installation for the best gas boilers.

ManufacturerModelBoiler TypeWarrantyStarting Guide Price
Worcester BoschGreenstar 8000CombiUp to 12 years£1,315
ViessmannVitodens 050-WCombiUp to 7 years£760
VaillantEco-Tec ProCombiUp to 10 years£845
Glow-WormEnergyCombiUp to 15 years£640
AlphaE-Tec PlusCombi10 years£670
Baxi600Combi7 Years£665
Worcester BoschGreenstar iSystemUp to 7 years£903
ViessmannVitodens 200-WSystemUp to 12 years£1,345
Worcester BoschGreenstar RiRegularUp to 10 years£680
VaillantEco-Fit ProRegularUp to 10 years£980

Which Gas Boiler Is Best Value for Money?

It can be tough to pick out the best value boiler because we’re all looking for something a little bit different to fit our heating and hot water needs. But, that said, the 15-year warranty and great price from the Glow-Worm Energy Combi is a fantastic deal. Then there’s the Greenstar Ri offering a great price and warranty, and it’s manufactured by Worcester Bosch, a company who consistently get positive feedback in their gas boiler reviews

How To Size A Gas Boiler

The size of boiler needed is generally assessed by how many radiators you have in the home and the type of boilers that’s installed.

Number of RadiatorsType of BoilerRecommended Boiler Size
Up to 10Combi24-27kW
Up to 10System9-18kW
10-15System or Regular18-26kW
15-20System or Regular27-40kW



There’s an immense choice within the gas boiler market. So, make sure that you really consider what’s important to you and select the right boiler for your home. You could also leave all the stress to Boiler Central and let us do the hard work for you! Simply answer a few questions about your hot water and heating needs, and we’ll make suggestions for the best boiler deals for your home and all with a fixed price, including boiler installation.

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