Vaillant Boiler Reviews 2021

Vaillant Boiler Reviews 2021

Vaillant has been setting the standards in heating for over 140 years and they were the company which pioneered the development of the combi-boiler over 35 years ago.

They are one of the largest companies in this sector across the whole of Europe and they manufacture world-leading products for heating installers, ventilation installers, and the renewable energy sector.

But how good are Vaillant boilers in 2021? Is one right for your home? In this review, we’ll cover:

• who Vaillant is
• what a combi boiler is
• the key stats you need to know about combi boilers and what they mean
• the top 10 Vaillant boilers according to HomeSage’s exclusive grading guide
• Vaillant vs other manufacturers – what do customers think?
• Vaillant’s top 5 gas small combi boilers up to 27kw
• Vaillant’s top 5 gas medium combi boilers from 28kw to 34kw
• Vaillant’s top 4 gas large combi boilers with 35kw+ output

It can be difficult to decide on which boiler is right for you and your property.

In this article, we’ve scored each of the top ten gas combi-boilers from Vaillant according to our exclusive grading guide. 

We’re HomeSage – we work alongside a network of trusted, established Gas Safe boiler installers up and down the UK.

We help to save you up to 54% on the total cost of the supply and installation of your new boiler – simply fill in a form anywhere on this page.

Once you have sent us your details, we forward these on to three local boiler installation companies in your area.

These companies are keen to give you the most competitive quote to win your order and some customers have reported a 54% difference between the highest and lowest quotes, so shopping around is always worthwhile!

Who is Vaillant?

Vaillant is a German company which began life way back in 1874. They are one of the oldest and largest manufacturers of heating and ventilation systems for domestic and commercial properties and they’re still a family-owned business today. 

They were the driving force behind the invention of the gas-fired bathroom boiler in 1894. This became the first method of hygienically heating water at home in the world.

They further pushed the boundaries of property heating with the development of the first central heating boiler and radiator combination in 1924. 

In 1961, the company produced the Circo Geyser for the first time. This was the very first wall-hung circulation water heater – a very early example of a combi boiler and an invention which spurred innovation across the sector as a whole.

What is a combi boiler?

Deciding on which type of boiler is best for your property needs careful thought and consideration beforehand.

The main difference between the types of boilers you can choose from comes down to whether the hot water you use is stored for later use or if it is heated instantly.

The combi boiler is the most popular type of boiler in the UK. Combi boilers heat the water which passes through them instantly meaning that you always have constant hot water in your home with no need to wait. 

However, water pressure can suffer if more than one person is using the hot water at the same time.

Don’t worry too much about that though, because a professional installer will advise you on which boiler you should choose for your property to reduce the chance of a drop in water pressure.

Gas combi-boilers are often the best choice for most residences as they require little space and they are more energy efficient than regular or system boilers.

They are available in a variety of specifications to fit the size of your house and number of bathrooms – Vaillant currently has 19 different combi-boilers on the market.

They can be easily installed within a kitchen cabinet or on the wall in your garage or utility room.

Check out our article on the best combi boilers on the market in 2021!

Key combi boiler stats

When it’s time to replace your boiler or if you’re renovating a property, deciding on what specification of boiler you need requires a bit of research.

To make sure you are making the most cost and energy-efficient choice, you should consider the flow rate, the boiler’s output (measured in kW), and its overall energy efficiency. 

Combi boiler flow rate

The flow rate of a boiler determines how many litres of hot water can come out of one or more taps within your home in one minute.

However, this is also dependent on the amount of water delivered by the mains supply.

The bottom line is that the higher the flow rate, the more powerful the boiler is and the quicker you can get hot water where you need it.

If your boiler has a flow rate of 14 litres per minute but the mains supply only delivers 10 litres per minute to your home, your maximum flow rate will still be 10.

However, if your flow rate is 11 litres per minute and the mains supply allows you 15, you get the full 11 litres from your boiler. 

Combi boiler output

A boiler’s output rate describes how much energy your boiler uses when it’s working and knowing it allows you to work out the cost of heating and hot water for your property.

To work out how much your running cost will be, you multiply the output by the price of a unit of gas.

Here’s an example – if your boiler has an output of 24kW and the price of a unit of gas is 4p, you will pay 96p for every hour the boiler is on and working.

It’s important to choose the correct output level for the size and needs of your property.

The more hot water you need or radiators you have to heat, the higher the output ought to be.

Combi boiler energy efficiency rating

When a boiler is switched on and working, a percentage of the energy it uses goes to heat the water with the remainder being used for non-core purposes – this is referred to as ‘lost’ energy.

Here’s an example, if your boiler is 90% efficient, you will have 10% of ‘lost’ energy. Newer styles of boiler are much more energy efficient than older, standard boilers – some of the older systems are only 60% efficient.

This is important because the more efficient a boiler is, the less it will cost to run and heat your home.

As with all modern domestic appliances, boilers are graded in their efficiency on a scale of A – G. If your boiler is 90% efficient or over, it is classed as grade A.

Vaillant’s top ten gas combi boilers

There are currently 19 different gas combi-boilers available from Vaillant. Here at HomeSage, we have created an original scoring system to rank each of these boilers to help you make an informed choice.

Our ranking system is based on:

• the energy efficiency of the boiler,
• the length of the warranty,
• users’ opinions on the manufacturer and aftercare service as found on Trustpilot, and
• the price point of the boiler

Our rating for the top ten Vaillant gas combi boilers are as follows:

How does Vaillant compare with other manufacturers?

Our findings show that Vaillant finishes third for the number of reviews available on Trustpilot and comes in joint fifth place with Grant with an average score of 4.6. 

If a company has the same average Trustpilot score as one of its competitors, we use the number of reviews to decide which manufacturer gets the better ranking.

So, if a company has more reviews, they will be placed higher up on the table. 

What do customers on TrustPilot say about Vaillant?

Happiness with the product

According to Trustpilot, generally users are happy with Vaillant products. They have over 10,000 reviews and 77% of them are in the ‘excellent’ category. 4% of customers deem them to be ‘average’ and 5% reviewed them to be ‘bad’. 

• Bert Warrilow reviewed that he received “Perfect service from initial survey, through installation, commissioning and handover, all conducted very professionally. The boiler is performing as required” on the 20^th June, 2020.

• Ehamaparanathan stated on the 19^th June 2020 that “the new boiler appears to be very compact and the parts can be easily accessed in the event of any fault unlike my earlier boiler. The thermostat can be operated manually and through the mobile phone. This feature may be very convenient for a person working long hours away from home and in winter could heat up his home from his workplace. This is too early to say how the boiler will perform over the next few years.” 

• On the 2^nd June 2020, Eric Hofer stated that “While I’m a repeat customer for Vaillant, I’ve had to replace boilers in a couple of properties on average, every 8 years. I don’t believe this is normal nor in keeping with the brand’s reputation. The main culprit has been rust and then issues with thermostats.”

• Roger Atterwil reviewed that there is “Constant low level buzz coming from the boiler whether it is working or not. Don’t like it at all” on the 18^th May 2020.

The guarantee period and after-sales service

As with any new boiler, you need to register it as soon as it’s installed to activate the extended guarantee.

Once you have done this, Vaillant’s guarantee covers you for the cost of repairing any defect incurred during the manufacturing process but the repair has to be undertaken by a Vaillant Service Engineer to cover both parts and labour costs.

The length of the Vaillant guarantee depends on the boiler you choose.

The length of the guarantees range from a standard 2 to 5 years although you do have the option to extend these to 7 to 10 years if required for an extra cost.

We had a look at some recent reviews on Trustpilot that refer specifically to the guarantee and after-sales service and here is a small selection of what we found:

• On the 17^th June 2020, Lynn reviewed that she received “Excellent service and contact from Vaillant UK; they gave me a list of recommended fitters in my area. I chose SH Heating. Scott Hyden was extremely knowledgeable and quoted me on the two systems I enquired about with no pressure from him to rush into fitting. He has also been very helpful to the tenants in the property setting them up on the app and guiding them on how to use it. I never needed to have any trips back and forth to the property while he was fitting the boiler. An absolute diamond of a worker.”

• Ann Hodson stated that “I was very pleased with the speed with which my boiler was installed, and with the visit a couple of days later to explain the workings of the new controller which I was having trouble sorting out” on the 17^th June 2020.

• A username titled Horrified in Guildford reviewed that they were “Very disappointed with Vaillant’s response when one of the advanced engineers registered on their website put in the wrong boiler, could not wire the system in and did not seal the flue outlet. Gas Safe condemned the installation. The plumber refused to refund and had already damaged my kitchen which he refused even to acknowledge. Vaillant said “once a unit leaves their warehouse it is no longer their responsibility“. I was left without heating at the coldest time of the year and had to pay another heating engineer to replace the whole system on the 23th May 2020.”

• Tony G reviewed on the 2^nd June 2020, stating ‘The boiler engineer was very unprofessional. He has not bothered giving any kind of paperwork that guarantees workmanship for a period of a year at least. You would expect that from a Vaillant authorised engineer. The boiler has no mechanism to switch off or on unless you do it at the mains plug and it keeps firing up even when you open the cold water. The Thermostat which is one of these wireless phone controlled ones, behaves in strange ways. I have only had the boiler in for 2 weeks plus, lets see how it behaves when the weather turns cold.”

The negative reviews did generally receive a follow up comment from Vaillant including a customer service number they could ring for further assistance.

Vaillant’s top 5 gas combi boilers up to 27kw

Gas combi boilers up to 27kW suit smaller properties like apartments or 1- or 2-bedroom terraced houses or flats which only have one bathroom.

Vaillant ecoTEC plus 825 Boiler (87.07% HomeSage score)

This is a smart, silver finished boiler that measures in at 720mm x 440mm x 338mm and it has a fold-down flap covering the control panel.

It’s not a compact boiler and it is unlikely to fit inside a kitchen cupboard but it’s always worth measuring up to check. 

The eco TECH range from Vaillant is intended to deliver high efficiency levels combined with high performance and great usability. 

Hot water is available in just 5 seconds’ time and this boiler is rated in band A for energy efficiency.

It has the ‘Quiet Mark’ accreditation and it comes with a step by step wizard setup for your fitter to make sure it is installed correctly and quickly.  

Vaillant ecoTEC plus 832 Boiler (86.83% HomeSage score)

The next step up from the Vaillant ecoTEC plus 825 would be the Vaillant ecoTEC plus 832.

It has the same sleek silver finish and is exactly the same size – at 720mm x 440mm x 338mm, so possibly not small enough to fit within a kitchen cupboard.

This model has a higher output and increased flow rate than the previous model and is still ranked as a category A for energy efficiency. 

Even with this output rate, the boiler might actually suit a property of 2 to 3 bedrooms and it would be capable of providing water for up to 2 bathrooms.

Vaillant ecoTEC Pro 24kw Boiler (85.04% HomeSage score)

This particular model mightsuit a home with 3 bedrooms but just one bathroom.

If you needed something with a little more power for more hot water taps, try the Vaillant ecoTEC plus 832 as reviewed above.

The Vaillant ecoTEC Pro 24kw measures in at 720mm x 440mm x 338mm like their other models in this range and it features an attractive slick silver finish.

It has a digital control panel but no flip-down cover.

With this boiler, you have the option of using Vaillant’s own smart thermostat technology – the vSMART.

It is simple to use and it is self-learning which means it remembers your favourite settings and heating habits for your convenience. 

Vaillant EcoFIT Sustain 825 Boiler (84.32% HomeSage score)

The Vaillant EcoFIT Sustain 825 Boiler is a compact boiler – the dimensions are 700m x390mm x 295mm so you could easily fit this into a kitchen cupboard out of sight.

The efficiency rating for this boiler just misses the A grade for environmental friendliness.

It comes in at 89.30% efficient and it is therefore classed as a grade B system.

If you like the sound of this system but you require a little more power, we recommend you have a look at the Vaillant EcoFIT Sustain 830 Boiler which has a slightly higher output.

Vaillant EcoFIT pure 825 Boiler (82.72% HomeSage score)

Rated as grade B on the energy efficient scale, this boiler measures a snug 700mm x 390mm x 295mm.

This boiler has a silver finish with an LED lit digital control panel on the front.

It has the ‘Quiet Mark’ accreditation so you won’t get any strange or disruptive noises but it only comes with a standard 2-year guarantee.

You do have the option to extend this at an additional cost however.

Vaillant’s top 5 gas combi boilers (28-34kw)

A medium-sized terrace or semi-detached house with up to 4 bedrooms and 3 bathrooms would require a boiler of 28-34kW. A 34kW boiler can heat up to 15 radiators.

Of the 9 Vaillant 28-34w combi boilers, here are the top 5 as ranked by HomeSage.

Vaillant ecoTEC plus 838 Boiler (86.45% HomeSage score)

As with all the ecoTEC boilers from Vaillant, this comes with a 5-year guarantee as standard.

It is ErP grade A in energy efficiency and it is hand-built in Derbyshire.

It features a silver finish and the control panel is hidden from sight behind a fold-down cover making it minimal in design.

The size of this boiler is a slightly larger 720mm x 600mm x 400mm so, for the location of the installation, it might be better for slightly larger properties with a utility room.

Vaillant ecoTEC plus 835 Boiler (86.40% HomeSage score)

This boiler has a slightly higher output than the Vaillant ecoTEC plus 838 but a lower water flow rate so it would be worth checking your mains supply flow to ensure you get the best fit. 

It is 720mm x 440mm x 372mm in size so it’s not as compact as other models available from Vaillant. 

The Vaillant ecoTEC plus 835 has a digital display which gives you diagnostics and fault codes.

This means it’s easier to solve any problems and that it could potentially reduce your call-out charges in the future because whoever’s repairing it will know what’s wrong.

Vaillant EcoFIT pure 830 Boiler (91.35% HomeSage score)

This boiler wouldn’t have any problem heating 15 radiators in a home that has 3 bedrooms and 1 bathroom.

If you have a smaller property with less radiators, this boiler would simply be too powerful and you would end up overpaying on your energy bills.

It is a compact boiler – 700m x 390mm x 295mm so it can be installed easily out of sight in a standard size kitchen unit. 

The Vaillant EcoFIT pure 830 is an intelligent boiler. When you don’t need as much heat in your property, it automatically reduces its output to 20%, meaning you will be saving energy and money.

Vaillant EcoFIt sustain 830 Boiler (83.72% HomeSage score)

The Vaillant EcoFIT sustain 830 boiler has a modulating high torque pump which means the boiler uses less energy.

It has a fairly high output at 30kW and a flow rate of over 12 litres per minute so it would serve a small to medium sized property of 3 bedrooms and 15 radiators well.

This range of boilers offer a good size-to-output ratio so you get all the hot water and heating you need but you’re safe in the knowledge you’re being environmentally friendly. 

This particular model is a compact 700mm x 390mm x 295mm and it comes in a light silver finish.

Vaillant ecoTEC Pro 30kw Combi Boiler (82.55% HomeSage score)

The Vaillant ecoTEC Pro 30kw Combi Boiler is slightly bigger than the Vaillant EcoFIT sustain 830 but it has the same output – so if you don’t mind that it won’t fit into a cupboard this could be a good choice.

The overall dimensions are 720mm x 440mm x 340mm and the boiler is finished in a silver colouring with a minimalist style control panel. 

The Pro range has a standard 2-year guarantee but as ever, can be extended at a cost to 7 years. 

Vaillant’s range of 35kw+ gas combi boilers (35kw+)

If you have a larger home which is semi-detached or detached and has up to 20 radiators and 3 or more bathrooms, you will need a boiler with an output of 35kW or greater. 

Here are the top 4 as ranked by HomeSage – please note that there are only 4 boilers whose output is greater than 35kw currently in the Vaillant range.

Vaillant EcoTEC Exclusive Green IQ 843 Boiler (85.81% HomeSage score)

The EcoTECH Green range from Vaillant are their best boilers in terms of efficiency, control and performance. 

This boiler comes with a full 5-year guarantee as standard which can be increased to 7 or 10 years at an extra cost if you would prefer for extra peace of mind.

It is 720mm x 440mm x 474mm in size so it’s not the smallest on the market but, with its high water flow rate and high output level, it would have no problem heating a larger home. It has a smart silver finish and a covered control panel.

Vaillant EcoFIT sustain 835 Boiler (84.20% HomeSage score)

This boiler has a high output of 35kW and it is part of the EcoFIT range. Dimensions-wise, the boiler measures just 700mm x 390mm x 295mm so it should fit easily into most locations into the home – particularly useful if you have in mind for its installation location a smaller area like a cupboard or a utility room.

It has a back-lit LED control panel which is easy to use and shows fault messages clearly to minimise the time needed by an engineer to diagnose any issues and put them right.

Vaillant EcoFIT pure 835 Boiler (82.18% HomeSage score)

The Vaillant EcoFIT pure 835 boiler is a grade ‘B’ in the energy efficiency score but it is one of the most compact measuring in at 700mm x 390mm x 295mm – so it can easily be hidden from sight in a cupboard or cloakroom.

As with the rest of the boilers in the EcoFIT range, it comes with a 5-year guarantee as standard.

Vaillant Home 35kw Boiler (90.16% HomeSage score)

The Vaillant Home 35kw boiler is a highly effective wall-mounted combi-boiler which would have no issue heating 20 radiators (perhaps more) around your home.

This boiler is compact (740mm x 418mm x 300mm) but powerful. We’re slightly disappointed by the 2 year guarantee on the unit but, in pricing terms, this is a bargain.

Save up to 54% on your new gas combi boiler

You can save up to 54% of the cost of the supply and the installation of your new boiler by leaving your details with us at any of the forms on this page.

We will contact three or four local, trusted and Gas Safe regulated engineers with your query who will get in touch with you for a free quote and relevant advice.

Our service is completely free for you and it is no obligation – there is no pressure to accept any of the offers from our partner installers if you decide not to go ahead.

Still unsure of what type of boiler, from what manufacturer, is best for you? Why not check out our other post on the best boilers in 2021 or the HomeSage Advice Hub for more info!