If you’re shopping around for a new combi boiler, you might be getting overwhelmed with all the options out there. With excellent boiler brands like Worcester Bosch, Viessmann, Vaillant, Baxi and more, making a decision to invest in a combi boiler brand becomes more challenging. Worry not! We’ve got you covered. In this blog, we will be discussing one of the best boiler brands on the market, Viessmann, we’ll discuss its history, reviews, prices, models and compare it against well-known boiler brands hoping to make the decision a little bit easier!
Viessmann History
The Viessmann Group is a German manufacturer of heating, industrial, and refrigeration systems headquartered in Allendorf, Germany.
It all started in 1928 when Johann Viessman laid down the foundations for heating solutions after being asked by a neighbour if he would build a boiler for his greenhouse. At that time, boilers were generally made from cast iron and reached operating temperature very slowly, however, for his neighbour, Johann developed and built a new model of boiler, made with steel.
Later, in 1947, Dr Hans Viessmann, the son of Johann took over his father’s company that had 35 employees at the time and grew the company to over 100 employees. By 1957 Viessmann Group grew to 350 employees and were producing over 5000 boilers a year.
By 1976, Viessmann started to produce solar panels, and in 1978 launched heat pumps in the world of heating solutions. And by 1988, Viessmann had sold his one-millionth Vitola boiler. What a success!
In 2017, the fourth generation of the Viessmann family, Maximilian Viessmann took on the role of Co-CEO alongside Joachim Janssen, and both strive to continue to create incredible products.
You can visit the Viessmann website for more information on the history of Viessmann.
Viessmann Reviews
Viessmann offers a full range of high-quality products that represent German engineering at its finest. Extremely reliable boilers that offer great performance are one of the reasons why Viessmann constantly picks up the Which? Best Buy award.
During the Which? Best Boiler Survey in 2021, 8,000 customers and 150 Which? Trusted Traders were asked to score Viessmann on their reliability, how likely they are to recommend their Viessmann boilers to friends and family, the build quality of their Viessmann boiler, the ease of servicing and availability of spares and parts and here’s the verdict:
Viessmann scored an overall 81% brand score. Customers and tradesmen gave Viessman an amazing 5 out of 5 stars for reliability and customer score, and a whopping 4 out of 5 stars for their overall engineer recommendation score, proving that Viessmann is a highly reliable and efficient boiler brand.
On the other hand, when looking at Viessmann’s Trustpilot ratings, we can instantly see that customers love their boilers and are more than satisfied. This is supported with an average rating of 4.5 out of 5 and over 3k reviews.
Here are some of the lovely words Viessmann’s customers had to say about their boilers: “First class in every respect from initial enquiry to completion.”
Another customer said, “Boiler swop, replaced 7 year old Ariston boiler with Viessmann Vitodens100 system boiler 6 months ago and Iam very happy with my new boiler,very quiet and future proofed to use hydrogen mixture gases when they become available.Ten year warranty is very reassuring and pleased to say the Viessmann recommended installer was very knowledgeable and proficient.”
Boiler Types (combi, system and conventional)
If you’ve decided you want a Viessmann boiler for your home, the next question is going to be which is the best Viessmann boiler for your home.
To answer this question, you will need to know whether you have a combi, system, or regular boiler. If you aren’t sure what boiler type you have, then this is a quick way to find out;
- Combi boilers don’t have any tanks, they heat water from the mains water supply
- System boilers have a hot water storage tank, usually, in an airing cupboard
- Conventional boilers have a hot water tank and a cold water storage tank (usually in the attic)
Combi boilers tend to be the best option for most UK homes as they don’t require storage tanks and offer heating and hot water on demand. System boilers are usually found in households with more than one bathroom in use at the same time (high hot water demand). Conventional boilers (also known as regular boilers) are useful for homes with low water pressure as they utilise a ‘gravity fed’ system but due to the tanks involved, most homes switch to a combi boiler when replacing a regular boiler.
Moving on, it’s time to discuss the top 5 Viessmann combi boiler models.
Viessmann Combi Boilers (Top 5)
1. Viessmann Vitodens 050-W Combi Gas Boiler
Viessmann Vitodens 050-W Combi Gas Boiler Key Features
- Weather compensation accessories
- A plug-in time clock
- Wireless receiver options
- Stainless steel heat exchanger
- User-friendly controls
- 7-day programming
- 7” colour touchscreen for maximum control and comfort in your home
- Integrated WiFi, meaning that it can be used with the ViCare app
- Built-in frost protection
- Easy to use controls
Viessmann Vitodens 050-W Combi Gas Boiler Prices
The standard price for a Viessmann Vitodens 050-W combi gas boiler 29kW is £858 and the 35kW retails for £862 (boiler only)*
2. Viessmann Vitodens 100-W Combi Gas Boiler
Viessmann Vitodens 100-W Combi Gas Boiler Key Features
- Backlit LCD touch-screen display
- Frontal access to the boiler for easy maintenance
- An Inox-Radial heat exchanger with an extended 10-year warranty
- Optional Vitotrol 100 controls
- 7-day timer
- Easy to use controls
Viessmann Vitodens 100-W Combi Gas Boiler Prices
The Viessmann Vitodens 100-W Combi Gas Boiler range is suitable for small, medium and large-sized homes and the price range is £844 – £1,104 (boiler only).*
3. Viessmann Vitodens 111-W Storage Combi Gas Boiler
The Viessmann Vitodens 111-W Combi boilers range is available in two kW outputs options of 26kW and 35kW. Thanks to its high-efficiency rating of 94% and an ErP A-rating, the Vitodens 111-W 26kW is classed as a very reliable combi gas boiler that stores domestic hot water within an integrated 46-litre unvented cylinder.
Viessmann Vitodens 111-W Storage Combi Gas Boiler Key Features
- Backlit LCD touch-screen display
- Frontal access to the boiler for easy maintenance
- Optional Vitotrol 100 controls
- 7-day timer
- Built-in temperature sensor
- Easy to use controls
Viessmann Vitodens 111-W Storage Combi Gas Boiler Prices
The Viessmann Vitodens 111-W Storage Combi Gas Boiler is also suitable for small, medium and large-sized homes. The range cost between £1,518 – £1,632 (boiler only)*.
4. Viessmann Vitodens 200-W Combi Gas Boiler
The Viessmann Vitodens 200-W Combi boiler range is available in two separate kW outputs; 30kW and 35kW. The Vitodens 200-W has an efficiency rating of 94%, meaning that this combi boiler can help you to reduce the cost of your energy bills. With a warranty of 10 years, you are guaranteed peace of mind with this reliable combi boiler.
Viessmann Vitodens 200-W Combi Gas Boiler Key Features
- Vitotronic 100 which is an optional constant temperature controller
- Quiet operation
- 7” colour touchscreen for maximum control and comfort in your home.
- Integrated WiFi, meaning that it can be used with the ViCare app
- Built-in frost protection
- Stainless steel heat exchanger
- MatriX-Plus burner
- Easy to use controls
Viessmann Vitodens 200-W Combi Gas Boiler Prices
You can buy the Viessmann Vitodens 200-W Combi Gas Boiler (without installation) for £1,150-£1,295 (boiler only)*.
5. Viessmann Vitodens 222-F Combi Gas Boiler
The Viessmann Vitodens 222-F Combi boiler range is available in kW outputs of 19kW, 25kW and 32kW. The Vitodens 222-F has an efficiency rating of 92%, making an A-rated boiler. This floor-standing storage boiler has a high flow rate of up to 20 litres per minute, perfect for larger homes with a higher demand for instant hot water.
Viessmann Vitodens 222-F Combi Gas Boiler Key Features
- Quiet operation
- 7” colour touchscreen for maximum control and comfort in your home
- Integrated WiFi, meaning that it can be used with the ViCare app
- Built-in frost protection
- Easy-to-use controls
Viessmann Vitodens 222-F Combi Gas Boiler Prices
The model range is ideal for all home sizes (Small, medium and large-sized) and the cost varies from £2,474 – £2,606 (boiler only)*.
Viessmann Combi Boiler Fault Codes
A combi boiler is a complex piece of equipment that works hard 24/7 all year round, and that’s why there’s a risk of things going wrong. Although boiler brands such as Viessmann, Vaillant and Worcester Bosch are super reliable (which means you’re less likely to have these issues), it’s still a good idea to know the common boiler fault codes.
If there’s a problem with your Viessmann boiler, it may display a fault code to let you know that it needs attention.
Generally speaking, a fault code helps the boiler engineer to quickly identify the problem with your boiler.
If you can see a fault code displayed on your boiler and you’d like to know what it means, read our guide on the ‘Viessmann boiler error codes/fault codes‘ list.
Warning– Always follow the boiler manual instructions and even if you know what the fault code means, make sure that a Gas Safe Registered engineer carries out the repair.
Viessmann Combi Boiler Warranty
Boiler warranties are there to give you peace of mind should things go wrong, but don’t confuse a boiler warranty with a guarantee! You can read our blog about the difference between both terms.
All new Viessmann boilers come with a standard manufacturer-backed warranty, ranging from 2 to 5 years (and a 10-year guarantee on the heat exchanger). However, when buying a new boiler through WarmZilla, you’ll get an extended warranty. Here’s a chart showing the standard and extended warranties breakdown:
| Model | Standard warranty | Extended warranty (When buying through WarmZilla) |
| Viessmann Vitodens 050-W | 3-year warranty | 10-year warranty |
| Viessmann Vitodens 100-W | 5-year warranty | 10-year warranty |
| Viessmann Vitodens 111-W | 5-year warranty | 10-year warranty |
| Viessmann Vitodens 200-W | 3-year warranty | N/A |
| Viessmann Vitodens 222-F | 3-year warranty | N/A |
Viessmann Combi Boiler Service
Having heating and hot water in your home is crucial, that’s why it is essential to ensure that you get your boiler annually serviced so that it can perform to its maximum efficiency.
Having your boiler serviced annually ensures greater reliability of your boiler, increases its lifespan, enhances safety for you and your home, and ensures that your boiler warranty is protected.
A typical boiler service consists of
- A full inspection of your boiler’s components by a Gas Safe Engineer.
- An inspection of the main injector, spark probe, and burner to the heat exchanger, electrical connections, and controls.
- Your Gas Safe Engineer should also check all the seals, pipework, and combustion releases to make sure that your boiler is functioning at the correct pressure.
- Replacement of any damaged or worn parts.
- Clean the necessary components to ensure your boiler is performing as effectively as possible.
When should you arrange a boiler service?
Your boiler manufacturer will often mention that your boiler requires an annual service to ensure maximum efficiency and to protect your warranty. If you don’t get an annual service, you could end up paying for repairs, which can be quite costly depending on the boiler fault.
Other signs that you should look out for that indicate that you need a boiler service are:
- If you see increased condensation in the room where your boiler is located
- Black stains or marks around your boiler
- The flame in your boiler changes from blue to yellow
If you start to feel nausea, tiredness, dizziness, start vomiting or having headaches, stomach pains or have difficulty breathing, please call your Gas Engineer immediately and vacate the property, as this could be a sign of Carbon Monoxide poisoning.
Viessmann Vs. Worcester Bosch Vs. Vaillant
We’ve compared 3 of the best combi’s on the market (Viessmann Vs. Worcester Bosch Vs. Vaillant) to have an overview of the options available to you.
Combi Boiler Comparison Table
| Viessmann Vitodens 050-W 29kW | Worcester Bosch Greenstar 4000 30kW | Vaillant EcoTec Pro 30kW | |
| Flow rate | 12 l/min | 12.3 l/min | 12.3 l/min |
| DHW kW Output | 29kW | 30kW | 30kW |
CH kW Output | 24kW | 24kW | 25kW |
| ErP Rating | A | A | A |
| Warranty | 3 years | 10 years | 10 years |
| Efficiency rating | 93% | 94% | 93% |
| Dimensions (mm) | H:707 x W:400 x D:350 | H:724 x W:400 x D: 310 | H:720 x W:440 x D:335 |
| Price* | £1,889 | £1,969 | £1,989 |
Straight off the bat, we can see that all three boilers are very similar in what they offer and their performance. To ensure that the comparison is fair, we have chosen boiler models with similar, if not the same kW outputs for central heating and hot water. For this blog, we are focusing on boilers with an output of around 30kW.
Thanks to these outputs, these boilers would be ideal for homes with up to 20 radiators and 2 bathrooms.
When comparing these three combi boilers, we can see that they all have a similar efficiency rating of between 93% and 94%, making them A-Rated boilers. What does efficiency rating mean? Well, the higher the rating, the more efficient your combi boiler is. If your combi boiler has an efficiency of 93%, this means that only 7% of the gases being used when your central heating system is turned on, is being wasted.
In financial terms, this means that for every £1 you spend on your central heating, only 7p of it is being wasted. This is why we recommend that when you are looking to purchase a new or replacement combi boiler, you should do your research into the boiler’s efficiency rating because cheaper boilers can often be a lot less efficient, costing you more money on your energy bills, in the long run.
One of the more noticeable differences is the warranty lengths. We can see from the table that the Viessmann Vitodens 050-W 29kW comes with a standard 3-year manufacturer’s warranty, which is significantly less than the warranty that the Worcester Bosch Greenstar 4000 30kW and the Vaillant EcoTec Pro 30kW come with.
It’s difficult to compare three boilers that are all classed as very robust, efficient, and reliable boilers, which is why they are three of the best-selling boiler brands on the market.
The prices vary slightly for all three combi boilers, which is the factor we will consider to choose our final winner. These prices are from our website and are based on a 3-bedroom semi-detached home with one main bathroom and no additional shower rooms.
Here are our final thoughts on which brand is the winner and why.
Vaillant comes in at 3rd place. This is because it is the most expensive boiler model of the three. The Vaillant EcoTec Pro 30kW is £20 more expensive than the Worcester Bosch, although it has a lesser efficiency rating of 93%.
In second place, is the Viessmann Vitodens 050-W 29kW. We have awarded the 050-W second place because of its warranty length. Although you would receive a 10-year warranty with WarmZilla, customers who may have bought elsewhere would have only received the standard 3-year warranty on this boiler. It also has the lowest flow rate of all three boilers.
This means that our winner in the battle between Viessmann, Worcester Bosch, and Vaillant is Worcester Bosch! Worcester Bosch is known for producing fantastic products that are compatible with different wireless controls. They are also known for their fantastic customer service and aftercare.
For this total cost of £1,969, you will be given a 10-year standard warranty, a reliable boiler with an efficiency of 94%, helping you save money on your energy bills, a brand new, sleek, modern boiler model that will satisfy your homes needs for many years to come.
Worcester Bosch has just been awarded a Which? Best Buy endorsement for the 12th year running, with its gas and oil boiler ranges being top-rated in the industry.
Viessmann combi boiler sizes
What kW size Viessmann boiler do I need for my home?
There are a few factors that can have a bearing on the kW boiler that would be best suited for your home:
1. Number of Radiators
The kW size boiler needed for your home will depend on the number of radiators that are fitted in the property. It is important to ensure that the kW is sufficient enough for the demand for hot water and central heating in your home.
What kW boiler do I need for
| 6 Radiators | 12kW boiler |
| 8 Radiators | 15kW boiler |
| 12 Radiators | 21kW boiler |
| 15 Radiators | 26kW boiler |
| 20 Radiators | 33kW boiler |
2. Home Insulation
Insulation plays a factor in your kW boiler requirements. A poorly insulated property suffers from poor heat retention and your boiler needs to work harder to keep the house at the same temperature.
Improving your cavity/loft insulation or upgrading your windows from single to double glazed will have an impact on heat retention. You can also buy thermal leak detectors from a reasonable price on Amazon to identify areas of your home where heat is escaping. Here are our top tips to winter-proof your home.
3. Water Pressure
Different areas can have different water pressure levels and older homes can have lower water pressure than newer homes. If your home has low water pressure, then you will require a higher kW boiler with a good flow rate to ensure you don’t suffer from a drop in pressure when multiple taps are running at the same time.
4. Maintenance
Like any piece of machinery, the better condition it’s in, the better it will perform. Giving your boiler an annual service is essential in making sure it keeps running smoothly in much the same way as a car.
We have included a table to help you find the most suitable kW boiler size for your home depending on what boiler type you have.
Combi Boiler kW Size Guide
| No of bedrooms and bathrooms | Poorly insulated property | Moderately insulated property | Well insulated property |
| 1 bed + 1 bath | 20kW | 20kW | 18kW |
| 2 bed + 1 bath | 20kW | 20kW | 18kW |
| 2 bed + 2 bath | 24kW | 20kW | 20kW |
| 3 bed + 1 bath | 28kW | 26kW | 24kW |
| 3 bed + 2 bath | 28kW | 28kW | 24kW |
| 4 bed + 1 bath | 30kW | 30kW | 28kW |
| 4 bed + 2 bath | 32kW | 32kW | 30kW |
| 5 bed + 2 bath | 40kW | 35kW | 30kW |
If you’re unsure what kW means when it comes to your boiler, check out our blog about it, or you can just complete the WarmZilla survey which will ask you about the number of rooms and bathrooms in your home, your demands and specifications, and then will give you the ideal boiler size for your home – without the hassle!
What’s included when buying a Viessmann combi boiler from WarmZilla?
When you purchase a new or replacement boiler with WarmZilla, your boiler package will also include:
- Your chosen boiler, along with the necessary flue kit needed for your central heating system
- Installation by a qualified Gas Safe Engineer
- Removal of your old boiler and parts
- A FREE system cleanse of your central heating system
- Chemical Inhibitor for added protection for your new boiler
- 10-years guarantee, which will be registered by WarmZilla after installation
- A FREE magnetic system filter for ongoing protection
- The Neomitis RF Digital Wireless Room Thermostat
FAQs
In a nutshell, yes! Viessmann offers a full range of high-quality products that represent German engineering at its finest. Extremely reliable boilers that offer great performance are one of the reasons why Viessmann regularly picks up the Which? Best Buy award.
The top 5 Viessman combis are; Vitodens 050-W, Vitodens 100-W, Vitodens 111-W, Vitodens 200-W and Vitodens 222-F.
There are a few factors that can have a bearing on the kW boiler that would be best suited for your home such as the number of radiators, home insulation, water pressure and maintenance.
