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Viessmann: A review of the brand (and their impressive boilers)

Which? Best Buy boilers, ruthless German efficiency and unbeatable performance from a manufacturing giant with a turnover of £2.4 billion. Europes 2nd largest boiler biz, Viessmann, are now taking over the UK market one review at a time.

Who are Viessmann? A brief review...

Viessmann Boilers

Viessmann make boilers. Very good boilers.

From a consumer point of view, that’s the short answer and the minimum information required. 

But for research and reassurance, we’ve gone into alarming detail below on each of their boilers and why Viessmann are relentlessly strengthening their grip on the UK boiler market like a python strangling a pig.

Viessmann Boilers Head Office

Viessmann Combi Boilers: A review of the range

Combi Boilers - Woah, wait – what even is a combi boiler? 

The UK’s most popular and – in most cases – most efficient boiler, requiring no cylinders or water tanks and providing instant hot water and heating to your radiators. It’s the pinnace of heating & hot water.

Crucial read for a newbie; Best Combi Boilers.

Viessmann Vitodens 050-W Combi Boiler

Available boiler sizes:
29kW & 35kW

Viessmann Vitodens 050-W Combi BoilerSurely the most outstanding ‘entry level’ boiler in the world of heating. The 050-W is the perfect combi for 1-2 bathroom homes. Through Heatable, the Vitodens 050-W can be acquired with an exclusive 10-year warranty at a staggeringly low price. Viessmann have described sales of the Vitodens 050 as similar to that of Range Rover sales to wealthy urban mothers.

We fit Vitodens 050's from just £1,695, all over the UK, within 24 hours - Get your fixed price online.

We recommend you enhance your home with an 050 without further ado. But delve further into its world by reading this here article.

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Viessmann Vitodens 100-W Combi Boiler

Available boiler sizes: 
26kW, 30kW & 35kW

Viessmann Vitodens 100-W Combi Boiler

With their Vitodens 100-W, Viessmann have achieved the near impossible in producing a sequel that can better the original. The 100-W – award winning again, of course – has improved upon the 050-W, replacing some internal rubber parts with a more sturdy copper and increasing the size and functionality of the boilers LCD display.

We fit Vitodens 100's from just £1,995, all over the UK, within 24 hours - Get your fixed price online.

Read more on the Which? Best Buy awarding winning 100-W here.

Viessmann Vitodens 200-W Combi Boiler

Available boiler sizes: 
26kW & 35kW

Viessmann Vitodens 200-W Combi Boiler

Completing a hat-trick of ‘Which?’ Best Buy awards, the Viessmann 200-W is  Viessmann’s pride and joy, their beautiful monster, their Dragon Queen. Somehow balancing outstanding power and efficiency, the Vitodens 200-W is also remarkably quiet and boasts Viessmann’s best design including a colour LCD touch screen display that would’ve once qualified as a wide screen TV.

Viessmann Vitodens 111-W Combi Boiler

Available boiler sizes: 
26kW & 35kW

Viessmann Vitodens 111-W Combi Boiler

Constantly striving for bigger and more powerful boilers with an almost psychotic tenacity, Viessmann birthed the beastly Vitodens 111-W. A combi boiler birthed from the unnatural and depraved coupling of combi & system boilers; the 111-W is a combi boiler that also boasts a built in hot water storage tank. The perfect solution for large family homes with regular and simultaneous demand for hot water.

Fancy treating your home to a V? Get your fixed price online.

Viessmann System Boilers:

Stop. Wait. What is a system boiler anyway? 

It’s a boiler with heating and hot water controlled separately – in addition to your actual boiler, you’ll have a pressurised hot water storage tank.

Viessmann Vitodens 100-W System Boiler

Available boiler sizes: 
19kW, 26kW, 30kW & 35kW

Viessmann Vitodens 100-W System Boiler

The 100-W is a Swiss Army Knife of system boilers, offering a compact design with whisper quiet operation, a stainless steel heat exchanger, a backlit LCD display that stares back into your soul and the CO2 output of a patronising vegan.

We fit Vitodens 100's from just £1,995, all over the UK, within 24 hours - Get your fixed price online.

Viessmann Regular (open-vent) boilers:

Hang on. What’s an open-vent boiler? 

Well, it’s very similar to a system boiler in that it will have a separate tank for hot water but additionally will have a cold water storage tank, usually in the loft of the property that gravity feeds water to your system. 

Viessmann Vitodens 100-W Regular Boiler

Available boiler sizes: 
13kW, 16kW, 19kW, 26kW & 35kW

Viessmann Vitodens 100-W Regular Boiler

Everything you have now come to expect from a Viessmann boiler – reliability, low carbon emissions, a compact size, quiet operation volume, a backlit LCD display and their almost cliché ‘Which?’ Best Buy award to top it all off. With the largest power output range, there’s an open vent Viessmann Vitodens 100-W for your home, whether you live in a shoe or a castle.

We fit Vitodens 100's from just £1,995, all over the UK, within 24 hours - Get your fixed price online.

Top reasons to invest in a Viessmann boiler

Massive warranties ☔

Boilers are the most used piece of equipment in UK homes. How often do you need heating and hot water? Exactly.

Having peace of mind that your boiler is protected in the case of breakdown – particularly in winter – is invaluable. Every Viessmann boiler fitted through Heatable comes with a  10-year parts & labour warranty as standard.

Amazing aftercare 🤗

Should you need to call upon your boilers warranty, it’s imperative that the service you receive is up to scratch – and fast. Viessmann attend the vast majority of warranty calls within 24 hours of receipt, with no call out charges.

German engineering 🇩🇪

Ever the pioneers, you can rest assured that your new Viessmann boiler has been engineered to within in an inch of its life, and then some. Having honed their trade creating super-efficient industrial boilers, Viessmann’s domestic range has inherited the standards required to heat grand factories full of hard working Germans.

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Ruthless efficiency 🤓

Whether it’s genuine concern for the environment or just a ruthless competitive nature from the Germans, they’re doing everything they can to keep their CO2 emissions low and so in turn, your energy bills. Everyone one of their boilers is rated A for efficiency. Every. Single. One.

European domination 🇪🇺

Viessmann boast a mammoth turnover of 2.4 billion Euros. Thanks in large, to the Europeans adoration of their boilers. Europeans, renowned for their love of style and efficiency, consume Viessmann’s like they do wine.

Competitive prices – for now 💰💨

Viessmann have been a sleeping giant in the UK for too long and have now embarked upon a mission to deliver incredibly high quality German boilers to the domestic UK market, making its competitors look like Smart Price kettles. To warm to the money savvy Brits – Viessmann are currently offering their superior boilers to consumers at incredibly low prices.

Top technical reasons to invest in a Viessmann boiler

Stainless steel heat-exchanger

Viessmann Heat Exchanger

One of the most vital internal organs of a boiler. Viessmann make every one of their boilers with stainless steel heat exchanger - a self-cleaning, boiler life extending miracle that most Worcester boilers can’t bring themselves to offer.

Built in shock arrestors

If your house has ever bellowed, whistled and creaked whilst your boiler is in use as though you’ve just started a game of Jumanji – it’s because your boiler doesn’t have a shock arrestor to stop this hell.

Viessmann boilers? Built in.

Combined PRV & condensate pipe

The pressure release valve of your boiler and the condensate pipes will very often require two holes in the exterior wall by your boiler. Viessmann combined this into one hybrid pipe, meaning one less hole blasted through either side of your lovely walls.

Compact size

Viessmann have achieved the unlikely feat of encompassing all of their award winning, eco friendly magic into amazingly compact case sizes whilst some of their competitors are still struggling with Honey I Blew Up the Boiler disasters, bursting out the airing cupboards of disgruntled boiler buyers.

Weather compensation

Viessmann are fully aware that you don’t always have the mental resources to decide what temperature your heating should be at, or what is most efficient. Which is why they offer a weather compensation device which cleverly compares the outside temperature to the ambient temperature in your home and adjusts your heating accordingly.

Smart tech compatible

Honeywell Smart ThermostatSmart thermostats are ever more popular, because releasing your gaze from an iPhone is the worst part of anybody’s day. Viessmann’s condensing boiler range are all fully compatible with smart technology. Add on a Honeywell T6 smart stat at the checkout when buying your new Viessmann through Heatable.co.uk.

Super quiet

Having your boiler in a frequently used room, particularly a bedroom can be a nightmare if your boiler cries like a hyena when it’s operating. Viessmann boilers have internal case padding to reduce noise pollution.

Viessmann boiler reviews

People review everything, usually to vent their frustration about how poor a product or service is. Rarely do us brits sing any praises, so prising positive reviews can be some-what of a challenge.

Viessmann aren't struggling at all.

Viessmann are smashing it.

Here's a quick snapshot of Viessmann boilers reviews from some of the top, UK review platforms.

Viessmann Truspilot Reviews

Viessmann Trustpilot Reviews

Rating: 8.4/10

Boiler is great - is working perfectly and operating quietly! Radiators definitely heating up faster than before
It's only been about 8 months since I've had the Viessmann boiler installed but no complaints so far, it is extremely efficient and very quiet, a big difference from the one it replaced.

Read Viessmann Reviews

Viessmann Reviews.com Reviews

Viessmann Reviews.com Reviews

Rating: 4.51/5

Good, efficient boiler, nice and quiet with a long warranty for peace of mind.
Following the installation of my Viessmann boiler I have been more than pleased with the performance of this unit. It is quiet, very efficient and totally reliable.

Read Viessmann Reviews

Viessmann Boilers vs. Worcester Bosch

We’ll take a look at two of their flagship models, side by side.

Viessmann Vitodens 050-W vs. Worcester Greenstar i

The ‘entry level’ boiler of both manufacturers and by extension, their best sellers.

  Viessmann 050-W 29kW Worcester Greenstar 25i
Outputs 29kW, 35kW 25kW, 30kW
Cost £1,695
(via Heatable)
£1,900+
Flow Rate 12.3L p/min 10.2L p/min
Size mm
(H x D x W)
707 x 400 x 350 710 x 400 x 330
Which? Best Buy
LCD Display
Efficiency A A
Heat Exchanger Stainless Steel Aluminium
Warranty 10 Years
(via Heatable)
5 Years


The Worcester Bosch Greenstar i has incredible sales numbers in the UK, but this – we think – is solely down to its brand name – Worcester.

When compared to any number of its competitors, it can be considered to be coming up short in numerous key areas, whilst still demanding a designer price like a Primark t-shirt with an Armani logo.

Verdict: When it comes to the entry level range here, there is only one clear winner. The Viessmann has the Worcester beat on all fronts whilst achieving a more competitive price too.

Viessmann Vitodens 100-W vs. Worcester Bosch CDi Classic

Two examples of more premium offerings from both manufacturers.

  Viessmann 100-W 30kW Worcester CDi Classic 29kW
Outputs 26kW, 30kW, 35kW 29kW, 34kW, 42kW
Cost £2,195
(via Heatable)
£2,400+
Flow Rate 12.4L p/min 12.3L p/min
Size mm
(H x D x W)
700 x 400 x 350 760 x 440 x 360
Which? Best Buy
LCD Display
Efficiency A A
Heat Exchanger Stainless Steel Aluminium
Warranty 10 Years 10 Years

Verdict: A much closer contest between two outstanding boilers you could never go wrong with choosing. In fact, we’ll only just give Viessmann the edge here on price and a more compact size.

Viessmann Boilers: The Review

Viessmann boilers are the home heating bargain of the century, that won’t be a bargain for much longer.

They’re flaunting their German superiority with a vivacious flare all over the nation and doing so with remarkably low prices in order to prise their way into the homes of British consumers like a double glazing salesman at month end.

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Respresentative finance example: Purchase price: £1,695, Deposit: £847.50, Credit: £847.50, Total repayable: 2.452.30, Duration: 120 months, Rate: 9.9% APR, Cost of credit: £496.11

[1] Price based on a like for like combi swap in a 2 bed, 1 bathroom terraced home with a standard flue

[*] Installation dates are subject to installer availability