Imagine a home where every room feels warm and cosy while your energy bills remain in check. The best gas boilers available in the UK can offer you exactly this.
There’s no single “best gas boiler” as the ideal choice depends on your needs and priorities. Consider factors like:
Price: Baxi 800 offers the most budget-friendly option.
Warranty: Ideal Vogue Max and Viessmann Vitodens 200-W boast extended warranty coverage.
Eco-friendliness: Worcester Bosch Greenstar 4000 prioritises energy efficiency.
Product range: Baxi 800 and Vaillant ecoTec Plus offer various models for various requirements.
Boiler size and type are crucial factors as well. Consulting a qualified heating engineer for a personalised recommendation is highly recommended.
And by comparing the best gas boiler models, it’s also critical to compare installers. This is because different installers offer different rates, so by comparing multiple installers, you not only avoid being ripped off, but also ensure you’re choosing only from the best boilers.
However, finding a trustworthy and qualified heating engineer to install your new gas boiler can be tricky and take up hours of your time. Thankfully, Boiler Guide can help you.
By filling in our 30-second form, we can connect you with up to 3 vetted heating engineers from our network.
To save you time and reduce the stress of finding the best gas boiler, we've done the leg work for you. By researching the biggest brands, taking an in-depth look at their latest and greatest boilers, we've compared customer reviews, industry awards and stand-out technology to find the best 5 gas boilers on the market today.
For each boiler, we've also asked the important questions:
How energy efficient is it? (Can it save you money on bills?)
Is it suitable for homes of different sizes?
Is it future proof? (Will it last the test of time and is there a long warranty to cover it?)
What's the environmental impact? And is this model ready
for future changes?
Each boiler in our list is available in different types and sizes to suit all homes, but if you would like more tips on buying a new gas boiler, check out our complete guide to finding the best boiler deal.
A recent Boiler Guide survey uncovered the top 5 brands most commonly installed (and most-loved) by homeowners. We've used the results, in the graph shown below, to form our best gas boilers list, by researching the very best boilers these popular brands have to offer.
1. Worcester Bosch Greenstar 4000
Price Range: £1,150 - £1,550 (excl. installation)
Types Available: Combi, System Efficiency: 93%-94% Home Sizes: Small – Large
Ranked as the number 1 choice of boiler brand in the recent Boiler Guide survey, Worcester Bosch has proven to be a popular, trusted manufacturer amongst homeowners.
The Greenstar range is consistently rated highly for reliability and quality and the new 4000 model, released in 2021, was quickly awarded as a 'Which? Best Buy' – so you can see why it's earned a spot in our top 5.
Worcester Bosch have stated the Greenstar is their most environmentally friendly gas boiler to date, which is a big claim ...but here's why:
This boiler comes in a range of outputs, which means you can choose the most appropriate level of power for your home. This ensures you don't waste money burning more fuel in a boiler that's too big for your needs.
An exciting new feature, known as 'Quick Tap' lets you indicate to your boiler (with one quick flick of the hot tap, on then off) that you want hot water – then when you go back to the tap a second time, the hot water is instant. This is a really interesting way of preventing water waste and also avoids that irritating wait for water to get hot on the chilliest of days.
Worcester Bosch has stated that their entire gas boiler range is capable of running on a 20% hydrogen blend. Hydrogen fuel is still in development, but this is a great step in future proofing this unit for a time when natural gas may be phased out as a fuel source. You can find out more about hydrogen gas in our guide to hydrogen boilers. If you want to know more about the gas boiler ban, visit our ‘when are gas boilers being phased out?’ guide.
Other plus points:
It's 'Quiet Mark' awarded – meaning it's one of the quietest gas boilers you can get
Wireless controls (with Bosch's 'EasyControl')
Its packaging is 99.9% recyclable
The system boiler is compatible with solar panels, for additional energy savings and reduced environmental impact
Types Available
Combi
System
Outputs
25kW, 30kW
12kW – 30kW
Efficiency Rating
A-rated (CH, DHW*)
A-rated
Warranty
Up to 10 years**
Up to 10 years**
*CH: Central Heating, DHW: Domestic Hot Water
**When fitted by Worcester Accredited Installer
Potential Cost: £995 - £2,100 (excl. installation)
Types Available: Combi, System, Regular (Conventional/Open Vent)
Efficiency: 92%-94%
Home Sizes: Small – Large
Ranking second in our home heating survey, Vaillant is another highly popular choice amongst engineers and homeowners.
EcoTec Plus is the flagship model for Vaillant and they can boast some incredible tech inside these highly efficient boilers.
By learning when you don't use it as much, this gas boiler can drop to 16% of its power to save fuel – and your pennies, win-win!
Vaillant claims they always aim for low energy consumption, high performance and ease of use, which we can see in the following features:
A-rated for hot water and heating efficiency
Hot water within 5 seconds
Simple backlit display
Quiet Mark awarded
Vaillant are currently testing all of their boilers to confirm compatibility with a 20% hydrogen blend. This is a good indication that these boilers may soon be secure for any possible gas supply changes.
Types Available
Combi
System
Regular (Conventional)
Outputs
25kW – 38kW
12kW – 37kW
12kW – 35kW
Efficiency Rating
A-rated (CH, DHW*)
A-rated
A-rated
Warranty
5 – 10 Years**
5 – 10 Years**
5 – 10 Years**
*CH: Central Heating, DHW: Domestic Hot Water
**Warranty may extend up to 10 years if a Vaillant Advance installer is used
Potential Cost: £1,300 - £1,850 (excl. installation)
Types Available: Combi, System Efficiency: 92%-93%
Home Sizes: Small – Large
Part of Ideal's premium range, the Vogue Max is made to be long lasting, stylish and reliable.
This gas boiler has a number of features similar to its companions in this list, but it does offer a few extras that make it stand out.
Ideal have designed their own magnetic system filter which comes with the boiler. This is a great tool that sits within your pipework and filters out all the impurities from your water. This can help to extend the life of the boiler, improve efficiency and reduce running costs. This filter also comes with a 10-year warranty, so it's a great bonus to the whole set-up.
Other noteworthy features:
Extensive 12-year warranty offer, including parts and labour
Lightweight design for quick and easy installation
Compact cupboard fit
Ready to run on a 20% hydrogen blend
Types Available
Combi
System
Outputs
26kW – 40kW
15kW – 26kW
Efficiency Rating
A-rated (CH, DHW*)
A-rated
Warranty
10 – 12 years**
10 – 12 years**
*CH: Central Heating, DHW: Domestic Hot Water
**12 year when installed and serviced by a Max accredited installer (other terms may apply)
Potential Cost: £1,100 - £1,540 (excl. installation)
Types Available: Combi, System, Regular (Conventional)
Efficiency: 93%
Home Sizes: Small – Large
The Baxi 800 range was created with the aim of providing an efficient and reliable gas boiler that would last.
This boiler also includes a magnetic filter, so users can feel confident their pipework is protected and maintenance issues will be kept at bay.
With the range available in combi, system, and regular versions, this boiler benefits homes of all sizes.
Highlights:
10-year warranty which includes parts and labour
Adey Micro2 magnetic system filter to protect the heating system and boiler
Compact design allows for installation within a kitchen cupboard
20% hydrogen ready
Types Available
Combi
System
Regular (Conventional)
Outputs
24kW – 36kW
18kW – 30kW
16kW – 30kW
Efficiency Rating
A-rated (CH, DHW*)
A-rated
A-rated
Warranty
10 years**
10 years**
10 years**
*CH: Central Heating, DHW: Domestic Hot Water
**Terms apply
Potential Cost: £1,700 - £2,400 (excl. installation)
Types Available: Combi, System Efficiency: 92%-94%
Home Sizes: Small – Large
Viessmann is another manufacturer with a great reputation. They are only the second brand of gas boiler to be given a 'Which? Best Buy' for 2021.
They rate highly for reliability and customer satisfaction and the 200-W model is perhaps the smartest gas boiler on our list.
This intelligent boiler has wifi capability which allows users to control everything via an app, making it highly convenient.
Viessmann can also boast that this model has a 98% efficiency capability – that's incredibly high! This makes it one of the most energy-efficient gas boilers you can get. Great for the environment and your savings.
Other features:
Viessmann's 'MatriX' cylinder burner improves energy efficiency, keeps the boiler healthier for longer and reduces environmental impact
Colour touchscreen
Quiet operation
12-year warranty available
Hydrogen ready
Types Available
Combi
System
Outputs
25kW – 32kW
11kW – 32kW
Efficiency Rating
A-rated (CH, DHW*)
A-rated
Warranty
10 – 12 years**
10 – 12 years**
*CH: Central Heating, DHW: Domestic Hot Water
**Terms apply
Out of the 5 best boilers we have reviewed in this article, any one of these boilers could be determined as the best depending on factors like price, warranty, product range, and your specific heating needs.
Product range: Baxi 800 & Vaillant ecoTec Plus
Price: Baxi 800
Warranty: Ideal Vogue Max & Viessmann Vitodens 200-W
Eco-friendliness: Worcester Bosch Greenstar 4000
Deciding on the type and size of the boiler you’ll need will also help you choose between these brands. We recommend that you seek professional advice from a heating engineer to help with this.
Get the best gas boiler price
We hope these 5 boilers have given you some insight into what is available in the world of gas boilers and what features are important to you. The next step is to consider how to get your new boiler at the best possible price.
Whilst boiler pricing can be straightforward, the cost of the installation can differ depending on a number of factors: How straightforward a replacement will be, if the boiler is to move position, if new pipework is needed, etc. That's why we always recommend comparing at least 3 quotes from qualified heating engineers.
Here at Boiler Guide we find the engineers, so you don't have to. Simply fill in our 30-second form and we will find up to 3 qualified installers in your local area who can provide you with free, no-obligation quotes.
The Worcester Bosch Greenstar takes the crown for best boiler and has also been given the “Which? Best Buy” award. This boiler is consistently highly rated for its reliability and quality.
What boilers do plumbers recommend?
Most plumbers typically recommend well-established brands such as Worcester Bosch, Baxi, and Viessmann. However, which specific boiler model is recommended to you will depend on your personal situation.
Which is the most economical gas boiler?
The Vaillant ecoTec Plus and Viessmann Vitodens 200-W are two of the most energy-efficient gas boilers on the market, with efficiency ratings of 94%. Having an efficient boiler is economical and will help keep your heating bills as low as possible.
Which combi boiler is the best?
The Vaillant ecoTec Plus and Worcester Bosch Greenstar are two of the top-rated combi gas boilers from our home heating survey. They’re highly rated by both engineers and homeowners for their reliable technology and efficiency.
Efficiency: 92%-94%