Viessmann vs Worcester Bosch Boilers – Which is best in 2024?

Witten by Bernard Morgan (Engineer) & Adam Apperley (Marketing). Published: January 19, 2024. Updated: April 24, 2024

Viessmann vs Worcester Bosch is a debate that’s been developing for a while. Comparing the two boiler manufacturers is important when deciding on a new boiler. It’s a big decision.

These are two of the best boilers in the UK. Worcester Bosch is better known in the UK, but Viessmann is the larger company worldwide.

In this guide, we’ll compare them based on the following criteria: new boiler cost, product range, quality of components, customer service, accolades and market share.

Our winner: Viessmann

Both Worcester Bosch and Viessmann offer quality engineering across their boiler ranges. However, when pitched against each other, including Viessmann boiler reviews, Viessmann stands out as the better boiler brand.

Viessmann tops all of our best boiler guides for a reason. Their components, notably the stainless steel heat exchanger and integrated WiFi, ensure Viessmann boilers are the best in the world.

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About Worcester Bosch

Worcester Bosch was founded in 1962 in Worcester, England. The company was bought by and has been a subsidiary of Robert Bosch GmbH since 1992. Manufacturing of boilers happens in Worcestershire, and its oil boilers are built at a site in Derbyshire. Their product range includes gas and oil boilers, hot water cylinders, heat pumps and solar water heating systems.

Worcester Bosch has been awarded ‘Which? Best Buy’ status for 14 years for its Greenstar gas boiler range.

About Viessmann

Viessmann was founded in 1917 in Germany and has been family-owned since its inception. They manufacture domestic and industrial heating and refrigeration systems and operate in 74 countries worldwide. Viessmann has operated in the UK since 1989 from its UK headquarters in Telford.

Whilst not as well-known as Worcester Bosch, Viessmann is increasingly gaining traction. This is due to its entire Vitodens range being awarded Which? Best Buy status for three years in a row. It’s also due to their premium internal components, including the stainless steel heat exchanger.

The Worcester Bosch boiler range

Below are three of the most popular Worcester Bosch boilers in the UK.

Worcester-Bosch-Greenstar-8000-Gas-BoilerWorcester Bosch Greenstar 8000

Size: 30kW, 35kW, 40kW 45kW or 50kW.
Efficiency: 94%.
Warranty: 12 years.
Price: Combi boiler available from £1,811 (boiler only price).

See our full in-depth review >

Worcester Bosch Heatslave II Oil Boiler

Size: 18kW 25kW or 32kW.
Efficiency: 94%.
Warranty: 10 years.
Price: Combi boiler available from £2,990 (boiler only price).

See our full in-depth review >

Worcester Bosch Greenstar 4000

Size: 25kW or 30kW.
Efficiency: 94%.
Warranty: 10 years.
Price: Combi boiler available from £1,541 (boiler only price).

See our full in-depth review >

Get Your Viessmann Boiler Quote Now!
Save up to £590 PER YEAR on your heating bills.
Getting a quote takes less than 1 minute. No obligation.
Save up to £590 PER YEAR!

The Viessmann Boiler Range

Below are a few of our best-selling Viessmann boilers. They focus on a few models to help reduce new boiler costs. It’s also worth noting that Viessmann is one of the only boiler manufacturers that offers storage combi boilers. These are great for homeowners who don’t want to install a full-system boiler but have high hot water demands.

Viessmann Vitodens 100-WViessmann Vitodens 100-W

Size: 11kW, 19kW, 25kW or 32kW.
Efficiency: 94%.
Warranty: 12 years.
Price: Combi boiler available from £1,427 (boiler only price).
Stainless steel heat exchanger. Available as combi, system and heat-only boilers.

Read our full, in-depth review of the 100-W 26kW combi boiler >

Viessmann-Vitodens-050-WViessmann Vitodens 050-W

Size: 19kW to 35kW.
Efficiency: 94%.
Warranty: 10 years.
Price: Combi boiler available from £1,060 (boiler only price).
Stainless steel heat exchanger. Available as combi and system boilers.

Read our full in-depth review of the 050-W 25kW system boiler >

Viessmann Vitodens 111-W Storage Combi BoilerViessmann Vitodens 111-W

Size: 25kW or 32kW.
Efficiency: 98%.
Warranty: 10 years.
Price: Boiler available from £1,980 (boiler only price).
Stainless steel heat exchanger. Internal 46-litre hot water tank.

Read our full, in-depth review of the 111-W boiler range >

Our thoughts on Viessmann vs Worcester Bosch

Worcester Bosch Boilers Review

  • Amongst the best build quality of any boiler range currently available in the UK
    Worcester Bosch has long been known for its build quality, and this continues across the range.
  • Great guarantee – 5 years as standard
    Worcester Bosch’s guarantee is comprehensive and covers replacement parts, callout and labour costs. To qualify for longer warranties a Worcester Bosch-trained installer must install the boiler along with a Worcester filter.
  • Boilers in the range feature manual override switches
    Should the thermostat fail, this will help on cold days.
  • Simple boiler controls across the range with clear information displays
  • Low risk of the condensate pipe freezing in severe weather conditions
    The Worcester Bosch range features condensate pipes that are highly resistant to freezing.
  • Compatible with a wide range of controls
  • Integrated low-energy pumps
  • Included frost protection

Viessmann Boilers Review

Below is a summary of our Viessmann boiler review.

  • Efficiency
    Efficiency is key to the Viessmann boiler range. It results from Viessmann’s investment in innovation and high-quality internal components. This has paid off with the Vitodens 200-W and the 111-W storage combi having efficiency ratings of 98% and no boiler in the Viessmann range dipping below 92%.
  • Innovation
    All internal components are copper and metal, where possible, rather than composite or plastic.
  • Quiet operation
    At just 36dB, the Vitodens 200-W is one of the quietest boilers available — quieter than an A-rated refrigerator. All Viessmann boilers have been engineered for quiet operation.
  • Weather compensation
    Utilising an outdoor sensor, Viessmann boilers can regulate the temperature of your home based on the temperature outside.
  • Stainless steel Inox-Radial heat exchanger (patented)
    Viessmann boilers, with their stainless steel heat exchanger retain efficiency for longer than boilers with aluminium heat exchangers. Stainless steel is more robust than aluminium for heat exchangers. Aluminium can lose as much as 10% efficiency over 10 years.
    viessmann boilers stainless steel heat exchanger
  • Industry-leading 12-year warranty
    Viessmann offers a standard 7-year parts and labour warranty. However, this is extendable to 12 years for the 100-w range and 10 years for other models if installed by a Viessmann-trained and authorised installer.
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Are Viessmann boilers any good?

Yes. Viessmann boilers are the best in the world. They use high-quality metal parts in their boilers where possible. They also have stainless steel heat exchangers and can be monitored by Viessmann themselves via the integrated WiFi.

Are Worcester Bosch boilers any good?

Yes. Worcester Bosch boilers are good. They have good efficiency and warranties. But their use of aluminium heat exchangers means we tend not to recommend them. They’re more prone to corrosion and failure and will lose efficiency over time.

Trustpilot Scores

The following are Worcester and Viessmann’s Trustpilot scores to save you the effort. As a new entrant into the UK market, Viessmann doesn’t have anywhere near as many reviews as Worcester Bosch. They’ve also not been on Trustpilot for as long. We’re confident that given more time Viessmann boilers will surpass Worcester.

Worcester Bosch

4.6 / 5 from 41,000+ Reviews. Rated ‘Excellent’.

Worcester Bosch 4.6 Out Of 5 on Trustpilot

Viessmann

4.2 / 5 from 4,500+ Reviews. Rated ‘Great’.

Trustpilot score of 4/5

Get Your Viessmann Boiler Quote Now!
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Getting a quote takes less than 1 minute. No obligation.
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Brand and Boiler Comparisons

Detail Viessmann Worcester Bosch
Heat exchanger Stainless steel Aluminium
Efficiency Up to 98% Up to 94%
Warranty 10-12 years 10-12 years
Weather compensation Yes No
Modulation range 1:8 to 1:17 1:10
Smart thermostat compatible Yes Yes
Noise Super quiet Quiet operation
On-boiler controls Touch screen Yes
Frost protection Yes Yes
kW outputs Up to 32kW Up to 50kW

Technology

Viessmann‘s innovation is industry-leading. They have great heat exchangers and premium parts and components inside the units. In addition, they have a range of heating control systems to choose from: the Climate Sensor, the Vitotrol 100-E or the Weather Compensation unit.

Worcester Bosch has their EasyControl smart thermostat. It allows control from anywhere in the world.

Efficiency

Viessmann‘s Vitodens 200-W and 111-W models can boast up to 98% efficiency. This is partly due to the stainless steel heat exchanger which is available across their whole range. The Vitodens 200-W also has a modulation range of 1:17, which means it can work at 1/17th of its full power to maintain a warm home.

Worcester Bosch boilers range from 90% to 94% efficient. Their aluminium heat exchanger means that good efficiency can be achieved. However, aluminium heat exchangers will degrade over time and lose up to 10% efficiency over 10 years.

Physical Size

Viessmann‘s boilers range from 300mm deep x 400mm wide x 700mm high for the Vitodens 050-W to a large floor-standing Vitodens 222-F storage combi boiler, which is 595mm deep x 600mm wide x 1,400mm high.

Worcester Bosch‘s Greestar 8000 Life is 365mm deep x 440mm wide x 780mm high.

Our Pick: Viessmann v Worcester Bosch

Both Worcester Bosch and Viessmann offer quality engineering across their boiler ranges. However, when pitched against each other, Viessmann boilers stand out as the better choice.

Winner: Viessmann

Viessmann tops our lists of the best boiler brands in the UK and the best combi boilers.

Quality of components

For us, Viessmann’s winning is mainly due to the quality of their components. Viessmann does not use plastic or composite materials for components where metal would be better. Nor do they utilise an aluminium heat exchanger like many other manufacturers, including Worcester Bosch.

It is the quality of their internal components which sets Viessmann apart from everyone else.

Stainless steel is more expensive to source and manufacture into heat exchangers than aluminium. Viessmann has invested in their boilers by manufacturing their heat exchangers in-house at their facility in Germany for industry-leading quality control.

Built-In Shock Arrestor

The built-in shock arrestor in Viessmann boilers reduces water hammer issues and is another excellent addition to these boilers.

Combined Pressure Relief Valve and Condensate

The pressure relief valve (PRV) and condensate are combined throughout the Viessmann boiler range. This gives the installers more choice in siting the boiler, allowing more flexibility with replacement, retrofitting, and new boiler installations.

Summary

Worcester Bosch and Viessmann are both fantastic manufacturers of boilers and heating systems.

For us, Viessmann comes top because they innovated with their stainless steel heat exchanger. They also stuck with brass and copper inside rather than plastic. This dedication to quality allows them to offer a full 12-year warranty on their 100-W boiler range.

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