Will Scholfield, Engineer
1 Aug : Updated 25 Mar ● 11 min read
Viessmann vs. Worcester Bosch boilers - An updated review and comparison for 2024
There are many things to consider when buying a new boiler, including the brand's reputation, your own specific requirements and, of course, the costs.
Viessmann and Worcester Bosch are two of the most respected boiler brands on the market, and they both have a wide variety of efficient and reliable options for new boilers.
If you’re in the market for a boiler replacement and doing your brand research, we’ve got you covered. Our team of experts here at BOXT have compared these two reputable brands, focusing on their ranges of combi boilers so you can decide which is the best option for you.
Choosing a new boiler brand can be overwhelming - if you’re not sure whether Viessmann or Worcester Bosch boilers are right for you, check out our other boiler comparison guides.
Who are Viessmann and Worcester Bosch?
Viessmann and Worcester Bosch are two big names in the boiler industry that everyone has likely heard of.
With their focus on boiler longevity and heating homes in the most efficient way, they’re both reliable brands when it comes to choosing a new boiler. Time to delve a little deeper into each of the boiler brands…
Introduction to Viessmann Boilers
Viessmann was founded in 1917 and is based in Allendorf, Germany, but manufactures heating equipment in 74 countries. Although the brand is relatively new to the UK market, its boilers are growing in reputation and popularity due to their energy efficiency and reliability.
The brand's current most popular combi boiler range is the Vitodens line which is becoming well-known for its brilliant technical specifications and dependability.
Introduction to Worcester Bosch Boilers
Formed in 1962, Worcester Bosch has long been the market leader in the UK after merging with the German-based Bosch group.
Worcester Bosch boilers are renowned for their high-quality manufacturing and the excellent aftercare they provide customers.
The brand's Greenstar boiler range features their most popular models of combi boilers and offers many different options in terms of power outputs and prices.
Viessmann vs. Worcester Bosch boilers: Pros and cons
At a glance, here is a round-up of the pros and cons of both Viessmann and Worcester Bosch boilers.
| Viessmann | Worcester Bosch |
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Pros
Cons
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Pros
Cons
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Viessmann vs. Worcester Bosch boilers: Technology
| Viessmann | Worcester Bosch |
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Some of the best technology Viessmann boilers offer include: The Viessmann Vitodens range of combi boilers can be equipped with Weather Compensation controls that use outdoor sensors to detect the external temperature and automatically adjust the temperature inside the home accordingly. This greatly reduces energy waste and can help users save money on their energy bills. |
Some of the best technology Worcester Bosch boilers offer include: Many Worcester Bosch combi boilers have smart thermostat capabilities, which can connect to Nest and Hive. This allows 7-day scheduling through a smartphone app, and smart home boilers like this give users greater control of their energy usage and efficiency. |
Viessmann vs. Worcester Bosch boilers: Size
Size is an important factor to consider when choosing a new boiler. Whether the boiler sits neatly inside a cupboard or is housed in the utility room, it needs to fit correctly so it doesn’t get in the way or stand out like a sore thumb in your space.
One of the benefits of installing combi boilers instead of other types, such as system boilers, is their compact size, and they can be hung on a wall in your home out of the way.
Check out the size comparison between Viessmann vs. Worcester Bosch boilers:
| Viessmann | Worcester Bosch |
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The Viessmann Vitodens 200-W combi boiler has a height of 700mm, a width of 450mm and a depth of 360mm. The other combis in this boiler range also have a similar small size. |
Worcester Bosch offers a full range of boiler types in different sizes. The Worcester Bosch Greenstar 8000 Life 30kW boiler, for example, has a slightly larger size of 780mm in height, 440mm in width and 365mm in depth. |
Although the Worcester Bosch model is larger than a Viessmann boiler, combi boilers from both brands are usually compact and can fit inside cupboards.
Viessmann vs. Worcester Bosch boilers: Features
| Viessmann | Worcester Bosch |
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Some of the best features of the Viessmann boiler range include:
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Some of the best features of the Worcester Bosch boiler range include:
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Viessmann vs. Worcester Bosch boilers: kW output
It goes without saying that your new boiler will need to be powerful enough to adequately heat your home, whatever its size.
System boilers are the right choice if you have a large house with more than one bathroom.
A combi boiler will have enough power to heat your home for people living in more standard-sized homes with 15 or fewer radiators.
| Viessmann | Worcester Bosch |
| The most powerful of Viessmann's combi boiler models is the Vitodens 200-W which has a maximum central heating (CH) output of 35kW and a maximum domestic hot water output (DHW) of 30.5kW. | The Worcester Bosch Greenstar 8000 Lifestyle range is available up to 50kW for combi and regular boilers and 35kW for system boilers, making this the most powerful combi boiler on the market. |
Viessmann vs. Worcester Bosch boilers: Efficiency
| Viessmann | Worcester Bosch |
| Due to its stainless steel heat exchanger with unmatched wall thickness, the Vitodens 200w combi can achieve incredible efficiency ratings of up to 98%. |
All of the gas boilers in the Greenstar range have an efficiency rating of at least 92%, and most of the models, such as the Greenstar CDi Compact, have 94% efficiency levels. The most energy-efficient Worcester Bosch boiler, the Greenstar 28CDi Compact, boasts an efficiency rating of up to 99.5% when working at 30% capacity. |
Viessmann vs. Worcester Bosch boilers: Warranty & guarantee
| Viessmann | Worcester Bosch |
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A Viessmann boiler will come with a 5-year parts and labour warranty as standard, but this can be extended to 10 years if a Viessmann-trained installer carries out the boiler installation. There are also chargeable options on certain models, such as the Vitodens 200-W combi that can extend the warranty even further to 12 years. |
Worcester Bosch offers a 10-year guarantee on their boilers as standard, which means that they will replace or repair your boiler without requiring an inspection. However, their labour and parts warranties vary depending on the model. For example, the Greenstar 8000 combi will have a 12-year warranty as long as a Worcester-accredited engineer installs it. |
Viessmann vs. Worcester Bosch boilers: Ratings & awards
| Viessmann | Worcester Bosch |
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Viessmann boilers were given the Which? Best Buy Status for three consecutive years in 2017, 2018 and 2019. They also received a 5 out of 5 score in the Which? Annual Boiler Survey, which ranks brands based on build quality, customer score, reliability and engineer recommendation. Viessmann also currently has a rating of 4.4 out of 5 on Trustpilot, which is based on over 3,500 customer reviews, and in 2019 they received the IF Design Award for the Vitodens 300. |
Worcester Bosch has a 4.6 rating on Trustpilot based on over 32,000 customer reviews, and they have had the Which? Best Buy Status for 11 years. They were also awarded the 'Best Domestic Boiler Manufacturer Award' at the 2020 Build Magazine's Home and Garden Awards for their products' outstanding performance and the brand's overall reliability. |
Viessmann vs. Worcester Bosch boilers: Price
When it comes to price, there's not a huge amount of difference between the two brands' premium models of combi boilers which reflects the high quality of their products.
If we take a look at two of their flagship boiler models:
| Viessmann | Worcester Bosch |
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The Viessmann 050-W 29kW comes at a cost of £1,695. |
The Worcester Bosch Greenstar 25i starts at £1,900. |
Check out our other boiler comparison guides
Working out which boiler brand is right for you?
Check out our Ideal vs. Baxi boilers comparison guide to help with your decision making
Ideal vs. Baxi BoilersViessmann vs. Worcester Bosch boilers: Models
We’ve compared the popular Viessmann and Worcester models - the Viessmann Vitodens vs. the Worcester Bosch Greenstar.
Viessmann boiler models
| Boiler Name | Fuel Type | Available in | Efficiency | Hot water flow rate | Warranty |
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Vitodens 050-W Combi Boiler | Gas | 25 kW, 30 kW, 35 kW | 92% | 10.2 l/min (25kW) 12.2 l/min (30kW) 14.3 l/min (35kW) |
Standard: 3 years Extended warranty for Trained Installer: 10 Years (additional fee applies) |
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Vitodens 100-W Combi | Gas | 26 kW, 30 kW, 35 kW | Up to 98% | 13.3 l/min (26kW) 15.6 l/min (30kW) 17.0 l/min (35kW) |
Standard: 5 years Trained Installer: 5 years Extended warranty for Trained Installer: 7, 10 or 12 Years (additional fee applies) |
| Vitodens 200-W 30kW Combi Boiler | Gas | 30 kW, 35 kW | Up to 98% | 15.69 l/min (30kW) 17 l/min (35kW) |
Standard: 3 years Trained Installer: 5 years Extended warranty for Trained Installer: 10 or 12 Years (additional fee applies) |
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Vitodens 050-W System Boiler | Gas | 19 kW, 25 kW | 92% |
Standard: 3 years Trained Installer: 7 years Extended warranty for Trained Installer: 10 Years (additional fee applies) | |
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Vitodens 100-W System Boiler | Gas | 11 kW, 19 kW, 25 kW, 32 kW | Up to 98% |
Standard: 5 years Trained Installer : 5 years Extended warranty for Trained Installer: 7, 10 or 12 Years (additional fee applies) | |
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Vitodens 200-W System Boiler | Gas | 11 kW, 19 kW, 25 kW, 32 kW | Up to 98% |
Standard: 3 years Trained Installer: 5 years Extended warranty for Trained Installer: 10 or 12 Years (additional fee applies) | |
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Vitodens 100-W B1GA Heat Only | Gas | 11 kW, 16 kW, 19 kW, 25 kW, 32 kW | 92% |
Standard: 5 years Trained Installer: 5 years Extended warranty for Trained Installer: 7, 10 or 12 Years (additional fee applies) | |
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Vitodens 111-W Storage Boilers | Gas | 25 kW, 32 kW | 98% | 20.1 l/m (25kW) 21.2 l/m (32kW) |
Standard: 5 years Trained Installer: 5 years Extended warranty for Trained Installer: 7, 10 or 12 Years (additional fee applies) |
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Vitodens 222-F Storage Combi | Gas | 19 kW, 25 kW, 32 kW | 94% |
Standard: 3 years Trained Installer: 5 years Extended warranty for Trained Installer: 10 or 12 Years (additional fee applies) |
Worcester Bosch boiler models
| Boiler Name | Fuel Type | Available in | Efficiency | Hot water flow rate | Warranty |
| Greenstar 8000 Combi Boiler | Gas | 30 kW, 40 kW, 45kW and 50kW | 94% | 12.3 l/min (30kW), 16.4 l/min (40kW), 18.3 l/min (45kW) 20.3 l/min (50kW) | Up to 12 years when installed by a Worcester Accredited Installer |
| Greenstar i Combi Boiler | Gas | 25kW, 30kW | 94% | 9 l/min (25kW), 10.8 l/min (30kW) | Up to 10 years when installed by a Worcester Accredited Installer |
| Greenstar Si Compact Combi Boiler | Gas | 25kW, 30kW | 94% | 8.9l/min (25kW), 10.7l (30kW) | Up to 10 years when installed by a Worcester Accredited Installer |
| Greenstar CDi Compact Combi Boiler | Gas | 28kW, 32kW, 36kW | 94% | 10 l/min (28kW), 11.5 l/min (32kW), 12.9 l/min (36kW) | Up to 10 years when installed by a Worcester Accredited Installer |
| Greenstar CDi Highflow Combi Boiler | Gas | 29kW, 30kW | 92% | 20 l/min (29kW), 25 l/min (30kW) | Up to 10 years when installed by a Worcester Accredited Installer |
| Greenstar Heatslave II Combi Boiler | Oil | 18kW, 25kW, 32kW | 90% | 15 l/min (18kW), 18 l/min (25kW), 22 l/min (32kW) | Up to 5 years when installed by a Worcester Accredited Installer |
| Greenstar 2000 Combi Boiler | Gas | 25kW, 30kW | 93% | 9 l/min (25kW), 10.8l/min (30kW) | Up to 6 years when installed by a Worcester Accredited Installer |
| Greenstar 8000 Life Combi Boiler | Gas | 30kW, 35kW | 94% | 12.3 l/min (30kW), 14.3 l/min (35kW) | Up to 12 years when installed by a Worcester Accredited Installer |
| Greenstar 8000 Style Combi Boiler | Gas | 30kW, 35kW, 40kW, 45kW, 50kW | 94% | 12.3 l/min (30kW), 14.3 l/min (35kW), 16.4 l/min (40kW), 18.3 l/min (45kW) 20.3 l/min (50kW) | Up to 12 years when installed by a Worcester Accredited Installer |
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Greenstar i System Boiler | Gas | 9kW, 12kW, 15kW, 18kW, 21kW, 24kW | 94% | Up to 10 years when installed by a Worcester Accredited Installer | |
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GB162 System Boiler | Gas | 50kW, 65kW, 85kW, 100kW | 93% | Up to 2 years |
Viessmann vs. Worcester Bosch boilers: Which boiler brand is best for you?
The Worcester Bosch and Viessmann boiler ranges are quite evenly matched regarding power outputs, and the prices of their premium combi models are fairly similar.
However, which boiler brand you choose will depend on the most important deciding factors for you and your home. In terms of warranty and reputation, Worcester Bosch is a clear winner.
Worcester Bosch is still the most trusted boiler manufacturer in the UK. Their range of Greenstar combi boilers is an excellent choice for people looking for a high-quality product with a long, 10-year warranty as standard.
If cost is one of the key deciding factors on your boiler buying journey, Viessmann boiler models start at a slightly lower price point without compromising on durability and efficiency. However, if you want to match the longer warranty period, it will come at an extra cost.
If you would like more information on boilers, you can read BOXT's boiler guides which will give you extra knowledge about boilers and their maintenance. Alternatively, get in touch with our team of experts today.
