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1,224 reviews

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1,224 reviews

Baxi or Vaillant: Boiler Comparison & Reviews

Alpha Boiler Warranty

Baxi and Vaillant are amongst the leading boiler manufacturers thanks to offering highly reliable and efficient boilers that are well reviewed by installers and homeowners.

When it comes to choosing a manufacturer for your next boiler, which is best: Baxi or Vaillant?

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Meet the brands: Baxi & Vaillant

Baxi are a UK manufacturer with over 150 years worth of experience having been established way back in 1866. They strive to deliver industry leading heating technology that’s highly efficient and the industry-leading warranties show how confident they are in their range of gas-fired combi, regular and system boilers.

Vaillant UK have put their 140+ years of experience to good use by leading the development of combi boilers – now the most popular boiler type installed across the UK. Their gas-fired boilers are some of the most efficient available on the market so whether your heating and hot water demands need a combi, system or regular boiler, Vaillant units can help to keep your energy bills down to a minimum.

Both Baxi and Vaillant are rated ‘Excellent’ on TrustPilot which goes to show the reliability that comes with the boilers available from both manufacturers.

Baxi boiler reviews

Baxi have built a strong brand in the UK as a reliable boiler manufacturer and their units are highly recommended by many boiler installers.

If you’re looking for flexibility with the installation of your next boiler then a Baxi might be the best option thanks to their units having a twin flue system. A twin flue can stretch to a distance of 15 metres at a diameter of only 80mm which means they can be installed in an internal cupboard away from external walls.

Vaillant boiler reviews

One of the most recognised manufacturers of quality boilers, Vaillant are well-reviewed by homeowners and installers alike.

A big benefit of installing a Vaillant boiler is how quiet they are during operation and is why they’re the only boiler manufacturer to be awarded the Quiet Mark accreditation.

When it comes to comparing Vaillant with other boiler manufacturers, they often come out on top thanks to having a stainless steel heat exchanger. Aluminium is the most common material for heat exchangers, and while it is effective, stainless steel offers many more benefits:

  • Extends potential lifetime of the unit
  • Helps to increase efficiency
  • Much less likely to need repairing

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Baxi & Vaillant boiler ranges

Baxi and Vaillant both manufacture combi, regular and system boilers that run on natural gas – with Vaillant also offering some LPG models too.

Combi boilers

A combi boiler is the perfect boiler for smaller properties with 1-2 bathrooms as they supply central heating and domestic hot water on demand, rather than storing hot water in a cylinder.

Both Baxi and Vaillant have a number of options when it comes to condensing combi boilers and comparing them can be a challenge.

Boiler Range Output Ratings (kW) Efficiency Rating Warranty
Baxi Combi Boiler Ranges
Baxi 200 24 & 28 89% 3 Years
Baxi 400 24 & 28 89% 5 Years
Baxi 600 24, 30 & 36 93% 7 Years
Baxi 800 25, 30 & 36 93% 10 Years
Baxi Duo-tec 24, 28, 33 & 40 88.6% 7 Years
Baxi EcoBlue Advance 24, 28, 33 & 40 89.1% 10 Years
Platinum 24, 28, 33 & 40 89% 10 Years
Vaillant Combi Boiler Ranges
ecoTEC Exclusive with Green iQ 35 & 43 94% 5 Years
ecoTEC Plus 25, 32, 35 & 38 89.3% 5 Years
ecoTEC Pro 24, 28 & 30 93% – 94% 5 Years
ecoFIT Pure 25, 30 & 36 89% – 89.4% 2 Years

A warranty period of up to 10 years is available when the boiler is installed by a Vaillant Advance Installer.

Regular boilers

There’s no shortage of output ratings for all the regular boiler ranges made available by Baxi and Vaillant, making it much easier for you to find the right boiler to match your home’s heating and hot water demands.

In terms of efficiency and warranty, the Baxi 600 Heat regular boilers are the best option between the ranges offered by Baxi and Vaillant.

Boiler Range Output Ratings (kW) Efficiency Rating Warranty
Baxi Regular Boiler Ranges
Baxi 200 Heat 12, 15, 18, 24 & 30 89.1% – 89.2% 3 Years
Baxi 400 Heat 12, 15, 18, 24 & 30 89.1% – 89.2% 5 Years
Baxi 600 Heat 13, 16, 19, 21, 25 & 30 93% 7 Years
Vaillant Regular Boiler Ranges
ecoTEC Plus 12, 15, 18, 24, 30 & 35 89.2% – 89.3% 5 Years
ecoFIT Pure 12, 15, 18, 24, 30 & 35 87.9% – 89.8% 2 Years

System boilers

They way system boilers is somewhere between combi and regular units. While, like a combi, system boilers heat water from the mains, they store hot water in a cylinder for use at a later time rather than providing it instantly.

Baxi system boilers are available with lengthier warranties than Vaillant models (7-10 years compared to 5 years) but the ecoTEC Plus and ecoFIT Pure ranges from Vaillant are the slightly more efficient units.

Boiler Range Output Ratings (kW) Efficiency Rating Warranty
Baxi System Boiler Ranges
Baxi Megaflo 15, 18, 24, 28 & 32 88.5% – 88.6% 7 Years
Baxi 600 15, 18 & 24 93% 7 Years
Baxi 800 18 & 24 93% 10 Years
Vaillant System Boiler Ranges
ecoTEC Exclusive with Green iQ 27 89.6% 5 Years
ecoTEC Plus 12, 15, 18, 25 & 30 94% 5 Years
ecoFIT Pure 12, 15, 18, 25 & 30 94% 2 Years
ecoTEC Plus 48 & 64 kW 48 & 64 94% 5 Years

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Baxi and Vaillant both have boilers endorsed by the Energy Saving Trust which will give you confidence they’ll help save you money on your energy bills.

As we mentioned earlier, the stainless steel heat exchanger found in Vaillant boilers helps to increase their efficiency. Baxi boilers, on the other hand, use aluminium heat exchangers.


In terms of price, there isn’t much difference between the boilers manufactured by Baxi and Vaillant. For all boiler types there’s a range of models available with a price tag suit higher and lower budgets. On the whole, the most affordable units are manufactured by Baxi which could help with your decision making.

Baxi Potential Cost Vaillant Potential Cost
Combi £625 – £1,385 £875 – £1,600
Regular £662 – £1,095 £790 – £1,500
System £740 – £1,127 £590 – £1,500


A standard Baxi warranty will see that you’re covered for 2 years but depending on the model you could be covered for as long as 10 years. No matter the length of the warranty, it will only cover the boiler itself and the integrated controls, not any additional accessories such as the thermostat.

Reading the terms of a warranty can be confusing but not when it comes to finding out more about Baxi boiler warranties as they’ve been approved by the Plain English Campaign, meaning that they’re simple to get your head around.

Vaillant boilers come with a standard warranty of between 2-5 years, covering the parts and labour. For even more peace of mind, many of their units offer the opportunity to increase it to 7-10 years when installed by a Vaillant Advance installer. During a Vaillant warranty, boiler component failures are covered but in the event that the fault is caused by contaminated water, you will be charged for the repairs.

Baxi vs Vaillant: the winner

There are benefits to having either a Baxi or Vaillant boiler installed but some of their advantages are different, which could make one more suited to your home than the other.

Although it might only be a slight advantage in some cases, Vaillant offer the more efficient systems which could come as a result of the stainless steel heat exchanger.

If you’re looking to relocate your boiler to a new location – especially if it’s away from an external wall – then Baxi is likely to be your best bet. The twin flue system offers greater flexibility when it comes to installation, making it much more likely that the boiler can be installed in your desired location.

Ultimately though, for many, the decision to go with one boiler manufacturer over another comes down to budget. More often than not, Baxi boilers are the cheapest option but it’s worth remembering that the stainless steel heat exchanger found in Vaillant boilers increases efficiency for lower energy bills, extends the life of the boiler and greatly reduces the risk of a fault.

So, while a Baxi boiler might be the cheaper upfront option, in the long run you may well be better off with a Vaillant boiler.

More boiler brands

If you want to continue you your search for a boiler manufacturer, the list of leading boiler brands extends beyond Baxi and Vaillant:

  • Ideal Boilers
  • Viessmann
  • Worcester Bosch
  • On the whole, all of these brands are also well reviewed by consumers and installers – compare their units using our Boiler Comparison Tool.

    Once you find the right boiler manufacturer for you, you’ll then need to find a heating engineer to carry out the installation. Hiring the right heating engineer is as important as installing the right boiler and that’s where we can help.

    By completing our simple online form, you’ll get free quotes from up to 3 boiler installers based in your local area. Getting more than a single quote will give you the greatest chance of finding the most competitive price.

    Need a new boiler?


    Get FREE quotes for a replacement boiler today.


Need a new boiler?

Get FREE no-obligation quotes now!

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