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Vaillant boilers review
Our latest boiler survey reveals what customers and engineers think about the high-end gas boiler brand, Vaillant.
Vaillant has a decent four-star customer score thanks to the vast majority of customers being likely to recommend the brand. But that only represents 20% of the overall rating.
The rest of the total score comes from our expert engineers' survey, as well as our reliability data for the brand.
Only Which? members can access our full results. Log in now or join Which? to find out the best boiler brands and how Vaillant boilers stack up against the competition.
Vaillant gas boiler score
We've revealed Vaillant's four-star customer score from its gas boiler owners, but only Which? members can access all of the survey data, including insights from boiler engineers and full reliability information.
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 |
|---|---|---|---|---|---|---|---|---|---|
Sign up to reveal Get instant access to this and all our scores and recommendations. Unlock tableFirst month £5, then £11.99 per month, cancel at any time Already a member? Log in |
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Get instant access to this and all our scores and recommendations.
Unlock tableFirst month £5, then £11.99 per month, cancel at any time
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From our May 2024 UK general public online survey of 10,028 people who are responsible for the maintenance of their boiler and our May-June survey of boiler engineers. This included 7,619 gas boiler owners, 1,387 electric boiler owners, 448 oil boiler owners and 230 Trusted Trader boiler engineers. The Total score for all types of boiler ignores price and is based on: Reliability (40%) How many boilers bought in the past six years developed a fault, factoring in time until first fault and severity. Fault had to be repaired by a trained plumber or engineer. Engineer score (40%) Made up of 15% ease of sourcing parts, 15% ease of replacing common components, 15% ease of servicing, 10% manufacturer support, 20% build quality, 25% unbiased recommendations (barring incentivised engineers). Customer score (20%) How satisfied owners are and likelihood to recommend a brand. Sample size of customers (1294). Best Buy threshold for gas boilers: 75%.
85% of customers who bought their boiler in the past six years were likely to be satisfied, three percentage points more than average satisfaction among all boiler owners.
Impressively, 37% of all the Vaillant boiler owners we heard from were 'very satisfied' – the highest rating they could give.
Vaillant engineers' review
Only Which? members can see engineers' reviews of Vaillant boilers.
We heard from 230 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 faults 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 Which? Trusted Traders 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 or 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 |
| 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 |
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 |
| 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.
Visit Vaillant to find out more about Vaillant boilers.
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