Viessmann Vitodens 100 W Review of the Gas Condensing Boiler

Looking for a new boiler and don’t know where to start? In this guide, we’re going to explore and review the Viessmann Vitodens 100 combi boiler as well as comparing it to the likes of Worcester Bosch.

After reading this quick guide, you’ll have everything you need to know to decide whether the Viessmann Vitodens 100 combi is the right boiler for you.

Do You Need A Combi Gas Boiler?

First of all, you’ll only want the Viessmann Vitodens 100 if your central heating system uses a combi boiler. That means it heats hot water on demand, so won’t have a cold feed in your loft, or a hot water cylinder. Other types of boilers are explained here.

Alternatively, just use this form to determine which boiler you need, the size and to get prices on screen.

Viessmann Vitodens 100 W Boiler: Overview

Here’s a few of the key things worth mentioning about the Vitodens 100 from Viessmann: 

  • Up to 10-years extended warranty
  • Suitable for properties with up to 3-bedrooms
  • Boiler Plus compliant
  • Smart thermostat compatible
  • 5% efficiency, meaning it’s A-rated
  • Available in 4.7kw-35kw outputs

According to Viessmann, it’s their best selling boiler. So, if you’re looking for a boiler from their brand, this is the one you should be looking at.

Product Warranty & Reliability

Although when most people think boilers, they think Worcester Bosch, Viessmann are always a brand worth mentioning. Both homeowners and engineers alike, consider Viessmann to be one of the most reliable boiler brands on the market.

And, that’s backed up by their warranty. Many boilers on the market today, come with as little as 2-years warranty. With the total cost of installation starting at around £1,800, that’s not much of a guarantee.

Minimum Years Warranty For A Boiler

If you’ve read any of our other reviews, you’ll know we always suggest a minimum warranty of 5-years. And of course, with a 10-year warranty, the Vitodens 100 blows that figure out of the water.

If Viessmann have that kind of confidence in their product, then so do we.

One of the reasons the Viessmann warranty is this long, is due to the stainless steel heat exchanger. When a heat exchanger fails, it can cost over £450 to replace. But, a stainless steel heat exchanger is going to last much longer than a standard unit.

Alternatives To The Viessmann Boiler

There are plenty of alternative brands offering a similar warranty. For instance, you can get a Worcester Bosch boiler with a similar warranty and at a similar price. Use this clickable form and you’ll get prices on screen within a matter of minutes.

*In order to get the 10-year extended warranty, the boiler needs to be fitted by a Viessmann Accredited installer. Without accreditation, your installer can only offer 5-years as a warranty.

Control Vitodens 100 Noise

Boilers, especially older ones, can be incredibly noisy. Typically, that’s a combination of a worn fan, and worn out pump. Together, they can make a heck of a noise.

Vitodens Combi Boiler

Viessmann have focused on making the Vitodens 100 combi as quiet as possible, and they’ve done this by setting up the internals of the boiler so that the fan can do it’s job, at an incredibly low speed.

The fan in your boiler helps to vent dangerous gases out of the flue, so it’s not just a case of turning it down, the whole boiler has to be designed to accommodate a fan running at a low speed. That’s something Viessmann have achieved, making the Vitodens 100 extremely quiet in the process.

Ease Of Use (LCD Touchscreen Display)

One of the first things you’ll notice with the Vitodens, is it’s sleek looking. And, that’s backed up with an LCD back-lit touchscreen display. That doesn’t just add to the styling of the Vitodens, it’s practical too.

Using the touchscreen display is a breeze in poorly lit rooms, and even in the dark.

Energy Efficiency & Money Savings

Although the initial outlay for a new boiler is something you could do without, there is a silver lining. Old boilers can be anything as low as 60% efficient. And a boiler like the Viessmann Vitodens 100, is over 89% efficient.

With heating accounting for around 55% of bills, that’s going to result in a huge cash saving. In fact, the Energy Saving Trust recently conducted a study that showed huge savings of up to £305 per year when a new boiler was installed.

Ironically, most companies now offer boiler finance, with packages as low as £12.94 per month, that means the boiler basically pays for itself (and then some), simply due to energy savings. By the way, if that’s the route you’re taking, there’s a guide to getting new Viessmann boilers on finance here.

Smart Thermostat Compatibility

Smart thermostats are part practical (energy saving and convenience), and part fashion; they look great.

With the Viessmann Vitodens 100, if you want to hook up a smart thermostat, you’ll have no problem doing so. You’ll be able to get the tado° installed with your boiler, and then install the tado° app on your smartphone to control it.

Vitodens 100 (Reviews)

Although checking out boiler reviews doesn’t consist of finding thousands on Amazon like you would with any other product, there are homeowner reviews out there. One of the best places to check out is

Currently, Viessmann have over 350 reviews, with an average rating of 4.5 stars. More importantly, 89% of people would recommend Viessmann as a brand.

Prices vs Worcester Bosch

Viessmann are a premium brand, and like all premium brands, a similar price tag is attached. Currently, you should expect to pay around £1,100 for the Vitodens 100-W boiler. Including all parts (flue, pipework, magnetic system filter and so on), as well as labour, the 30kW is likely to cost around £2,100 to get installed. Give or take.

HEATABLE Viessmann Vitodens 100-W

As a direct comparison, you’d be looking at something like the Worcester Bosch 30si. Typically, that’s going to cost around £1,150, so around £50 more.

But, there is a way to get Worcester boilers cheaper, too. And that’s also with HEATABLE.

Worcester Bosch Greenstar Si Compact 30kW

So here you have it, a comparable quote for a Worcester, and Viessmann combi boiler..

You can get quotes from local installers for a Viessmann Vitodens here.

Or, if you’d prefer a Worcester boiler, you can get a fixed price online here, from HEATABLE.

Conclusion On the Gas Condensing Boiler

Thanks for reading our quick review of the Viessmann Vitodens 100. We regularly write up how-to guides and boiler reviews, so bookmark our homepage. Feel free to use our search bar to find answers to any questions about Viessmann or other boiler brands you might have.




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