27 Feb 2024

Vaillant boilers review

Vaillant is a premium gas boiler brand, but our survey has revealed whether these pricey boilers have the quality to back it up

Christina WoodgerSenior researcher & writer

In this article

Vaillant gas boiler score
Engineers' review
Vaillant boiler reliability
Where to buy Vaillant boilers
Vaillant boiler costs
Are Vaillant boilers efficient?

Our latest boiler survey reveals what customers and engineers think about the high-end gas boiler brand, Vaillant.

Vaillant has an excellent 88% score for customer satisfaction thanks to the vast majority of customers being likely to recommend the brand, but that only represents 20% of the overall rating.

For members only, we've also found out whether engineers think as highly of Vaillant gas boilers as customers do, and the real fault rate of these boilers.

Log in join Which? to see how Vaillant compares to rival brands like Baxi, Ideal and Ariston.

Vaillant gas boiler score

We've revealed how happy Vaillant gas boiler owners are, but only Which? members can access all of the scores, including insights from boiler engineers and full reliability data.

Log in now to view the full results in the table. If you’re not yet a member, join Which? to get instant access to all of our reviews.

Best Buy	Reliability	Customer score	Overall engineer score	Ease of sourcing	Ease of replacing	Build quality	Manufacturer support	Unbiased recommendation	% Score

88% of customers who bought their boiler in the past six years were likely to be satisfied, one percentage point more than average satisfaction among all boiler owners. Impressively, 44% of all the Vaillant boiler owners we heard from were 'very satisfied', the highest score they could give.

Engineers' review

We heard from 198 expert engineers who scored boiler brands on several tests. We asked them to score gas boiler brands on the following:

The ease of sourcing spare parts.
How easy it so to change a common component (a heat exchanger).
The ease of servicing the brand's boilers.
The build quality of the brand's boilers.
The quality of technical support provided by the manufacturer.
Whether or not engineers would recommend the brand to consumers (we filter out incentivised and brand affiliated engineers).

We aggregate all of these scores and use them to create our overall engineers' score, which is 40% of our total brand score.

Which? members can see how engineers rated Vaillant gas boilers on all of these tests by logging in. Join Which? to unlock our full analysis.

Vaillant boiler reliability

Boilers are major purchases you should only make once every 10 to 20 years. You can keep yours for longer if you get it regularly serviced and if you get faults fixed quickly.

We asked people who bought a boiler in the past six years about whether it's fault-free. When faults are reported, we measure how serious the fault was, how long it took for the first fault to happen, and we make sure it was fixed by an engineer.

Using this data, Which? members can see which brands produce boilers that are less prone to fault than others.

Log in to to find out how reliable Vaillant boilers really are. Or if you're not a member, join Which? today for full access to our survey results.

Where to buy Vaillant boilers

It's easy to rush into making a decision, especially if your boiler breaks down in winter, but we recommend getting quotes from a couple of qualified heating engineers and comparing costs. Our Trusted Trader service can link you up with vetted boiler installers in your area.

You could also buy a boiler yourself and then hire an installer, but do seek expert advice before doing so: have your current heating system assessed and identify the type of boiler that meets your specific needs. If you do buy a boiler without having an installer lined up, you could struggle to find someone to set it up. Plus, an installer may have access to trade or wholesale prices, and will be able to recommend a model based on a professional assessment of your home and heating system.

Where to buy a boiler – find out what your options are

Only a Gas Safe Registered engineer/installer can install a new boiler: it's both dangerous and illegal to do so yourself if you're not qualified.

Vaillant boiler costs

Combi boilers

Boiler name	Sizes available (kW)	Standard warranty (years)	Extended warranty (years)	Price range (smallest kW output and biggest kW output)
ecoFIT Pure	25; 30; 35	2	10	£2,044 to £2,575
ecoFIT Sustain	25: 30; 35	2	10	£1,658 to £2,108
ecoTEC Sustain	24; 28; 34	5	10	£1,380 to £1,844
ecoTEC Pro	24; 28; 30	5	10	£2,206 to £2,558
ecoTEC Exclusive	25; 30; 35; 43	5	10	£1,658 to £3,693
ecoTEC Plus	26; 32; 36; 40	5	10	£2,555 to £3,808

Regular boilers

Boiler name	Sizes available (kW)	Standard warranty (years)	Extended warranty (years)	Price range (smallest kW output and biggest kW output)
ecoTEC Plus	12; 15; 18; 24; 30; 35	5	10	£1,713 to £3,374
ecoFIT Sustain	15; 18; 30	2	10	£1,311 to £1,541

System boilers

Boiler name	Sizes available (kW)	Standard warranty	Extended warranty (years)	Price range (smallest kW output and biggest kW output)
ecoFIT Pure	12; 15; 18; 25; 30	2	10	£1,888 to £2,722
ecoFIT Sustain	15; 18; 30	2	10	£1,331 to £1,470
ecoTEC Exclusive	27	5	10	£2,918
ecoTEC Plus	10; 12; 15; 18; 20; 24; 25; 30; 35; 37	5	10	£1,018 to £3,235

How expensive are Vaillant boilers?

Vaillant boilers cost more than the average across all brands, as its ranges are more concentrated on premium models.

Are Vaillant boilers efficient?

New boilers must be A-rated, but how efficiently your boiler works in practice depends on several factors, including how you use it and how well it's installed. Use a Which? Trusted Trader for your boiler installation and regular maintenance.