Viessmann Vitodens 100-W Combi Boiler Review

Posted on 18th June 2026

Why Choose the Viessmann Vitodens 100-W Combi Boiler?

The Viessmann Vitodens 100-W combi boiler is one of the top-rated and bestselling options in the UK. It consistently ranks highly in independent reviews and has repeatedly earned Which? Best Buy status for its reliability, performance and overall value.

The unit alone typically costs around £1,300 to £1,500 depending on output, with a fully installed price usually landing between £2,300 and £2,800 once flue work, a filter and commissioning are included.

Key Features and German Engineering

This is Viessmann’s mid-range powerhouse, showcasing German engineering at its finest. It features a durable stainless steel Inox-Radial heat exchanger with brass and copper internals for toughness and corrosion resistance, ensuring long-term performance even in varying water conditions.

Operation is whisper-quiet thanks to an advanced fan design, and it achieves up to 94% efficiency, translating to noticeable savings on energy bills.

The boiler is compact for easy installation, hydrogen-blend ready for up to 20% blended gas to help future-proof against greener fuels, and comes with a user-friendly backlit LCD touchscreen for intuitive control.

Smart Controls and Connectivity

One standout feature is the built-in WiFi, allowing seamless integration with the ViCare app. This enables remote scheduling, real-time monitoring, energy usage insights and remote diagnostics, useful for busy households or time away from home.

Pair it with Viessmann’s smart thermostat for even greater control and efficiency gains. For a smaller footprint at a lower price point, the Viessmann Vitodens 050-W covers the same core reliability in a more compact, budget-friendly package.

Reliability, Warranty and User Feedback

Homeowners and installers alike praise the Vitodens 100-W for its consistent hot water delivery, low running costs and impressive longevity, with many units lasting 15 or more years given proper maintenance and annual servicing.

It offers a market-leading warranty of up to 12 years when installed by a Viessmann-accredited engineer and paired with a system filter, providing excellent peace of mind. Its Which? Best Buy status reflects strong reliability data from independent testing.

Is the Viessmann Vitodens 100-W Right for You? A Balanced Review

Comparing it against numerous boilers on the market, the Vitodens 100-W strikes an ideal balance: premium quality and features without the ultra-high price tag of top-tier models.

It costs more than the entry-level Vitodens 050-W but justifies it with built-in WiFi, superior hot water flow rates, and that extended warranty, making it better long-term value for most users.

For households with very high hot water demand, such as multiple bathrooms in constant use, the Vitodens 111-W with integrated storage offers even faster recovery. For the majority of small to medium UK homes, though, this model blends efficiency, smart technology and German reliability well.

Final Recommendation

Overall, anyone seeking a high-end combi boiler that delivers on performance, smart features and durability without excessive cost will find the Viessmann Vitodens 100-W a standout choice. It suits homeowners prioritising quality engineering and future-ready technology.

For a look at what the step up buys, the Viessmann Vitodens 200-W covers the flagship model’s pricing and long-term savings, useful for comparing value before committing to either.

Specs Table for the Vitodens 100-W

Outputs: 26kW, 30kW, 35kW. The 30kW suits most homes.

Specification	26kW Model	30kW Model	35kW Model
Central Heating Output	Up to 26kW	Up to 30kW	Up to 35kW
Hot Water Flow Rate	~11-12 l/min (35°C rise)	~12-14 l/min	~14-16 l/min
Energy Efficiency	ErP A-rated (94%)	ErP A-rated (94%)	ErP A-rated (94%)
Dimensions (H x W x D)	700 x 400 x ~350mm	Same	Same
Weight	~35-38kg	~38kg	~38kg
Noise	Whisper-quiet	Whisper-quiet	Whisper-quiet
Warranty	Up to 12 years (accredited + filter)	Up to 12 years	Up to 12 years
Best For	Smaller homes, 1 bath	Medium, 1-2 baths	Higher demand

How Does the Vitodens 100-W Compare to the 050-W and 200-W?

Viessmann’s Vitodens combi tiers:

050-W: entry-level, excellent value, covers the essentials.

100-W: mid-range bestseller, smart features, premium build.

200-W: flagship, ultimate modulation, advanced tech.

Feature	Vitodens 050-W	Vitodens 100-W	Vitodens 200-W
Range Positioning	Entry-level/value	Mid-range/most popular	Premium/flagship
Best For	Small-medium homes, budget quality	Medium homes, smart & reliable	Larger homes, max performance
Hot Water Flow Rate	~12 l/min	~12-14 l/min	Up to 18-20 l/min
Efficiency	94% ErP A-rated	94% ErP A-rated	Up to 98%, superior modulation
Noise Level	Very quiet	Whisper-quiet	Super quiet
Design & Controls	Basic touchscreen	Backlit LCD touchscreen, built-in WiFi	Premium touch, advanced diagnostics
Warranty (accredited)	Up to 10 years	Up to 12 years	Up to 12 years
Relative Price	Cheapest	Mid	Most expensive

The 100-W suits most homes best, offering premium durability and smart features over the 050-W, without needing the extras of the 200-W.

FAQs

Is the Viessmann Vitodens 100-W a Good Boiler?

Yes. It’s Viessmann’s best-selling model in the UK and a repeat Which? Best Buy, combining a 94% efficiency rating with a stainless steel Inox-Radial heat exchanger and a warranty of up to 12 years when installed and registered correctly.

How Much Does a Viessmann Vitodens 100-W Cost Installed?

The unit typically costs £1,300 to £1,500 on its own. A full installation, including flue work, a system filter and commissioning, usually totals £2,300 to £2,800 depending on property complexity.

What Size Vitodens 100-W Does My Home Need?

The 26kW model suits smaller homes with one bathroom, the 30kW suits most medium homes with one to two bathrooms, and the 35kW is better for higher hot water demand across multiple bathrooms.

Does the Vitodens 100-W Need a System Filter?

A system filter is required to unlock the full 12-year warranty when paired with a Viessmann-accredited installation. Without one, the standard warranty term is shorter.

Is the Vitodens 100-W Hydrogen Ready?

It’s compatible with a hydrogen-blended gas supply of up to 20%, in line with current UK gas grid trials, which helps future-proof the boiler as blended fuels roll out more widely.

How Long Does a Vitodens 100-W Typically Last?

Many units run for 15 years or more with annual servicing and proper maintenance, helped by the corrosion-resistant stainless steel heat exchanger.

Is the Vitodens 100-W Better Than the Vitodens 050-W?

For most households, yes. The 100-W adds built-in WiFi, stronger hot water flow rates and a longer warranty, which usually justifies the higher price over the entry-level 050-W.

Does the Vitodens 100-W Work with Smart Thermostats?

Yes. It integrates with the ViCare app for remote scheduling and monitoring, and pairs with Viessmann’s own smart thermostat for additional control and efficiency gains.