Our Honest Thoughts On The Major Boiler Manufacturers & Their Products

09 May. 2019

Written by Neil Marsh MCIPHE RP RHP EngTech

This article aims to advise our customers and the general public on the pros and cons of the major brands at present based on our experiences and opinions. We are often asked “what is the best brand?”, of which we are unable to give a straight answer, as this article shows, it can be a complicated affair because there are many aspects to consider when buying a boiler…

Each engineer will have their own preference based on their own experiences, values and logic, but our aim here is not to discredit their view, or that of others, but to inform the general consumer so they can come to their own conclusions and pick a product that suits their expectations best. Certainly, at present, we are strong believers of there is no such this as the “Best Brand”, only some doing better than others in different areas. This is frustrating for ourselves, as we wish there was one brand that built the products we expect throughout their entire range, provided exceptional aftersales and put their money where their mouths are with long solid warranties/guarantees, but there is not. 

We hope you find this article informative and hope that not too many people within the industry throw their toys out of the pram about points we have raised. 

Worcester Bosch

Worcester Bosch are the market leaders within the UK for domestic gas boilers. Although they are the most popular, it is of our opinion that this is due to good marketing and over-hyping of their products, not because they make the best boilers!

Without a doubt, for a good number of years now, Worcester Bosch have provided the best aftersales service out of all the major suppliers. However, over the last twelve months or so there have been increasing reports of customers being unable to contact Worcester by phone for such things as warranty repairs and get a response from written communications, such as e.mails. This can be confirmed by reviewing the negative comments left on such resources as Trustpilot. 

Worcester does have a large dedicated team of in-house engineers who look after warranty related work and older Worcester boilers, but given what appears to be a decline in their customer service, it is possible they are struggling to cope with the large corner of the market they have. What the actual reasons for this reported decline in function are unsure, but without a doubt, we have heard more negative reports as of late in regards to their aftersales. On a positive note, Worcester does have a long history of a high first-time fix rate when they attend and are more likely to replace a part under their guarantee that has become defective due to poor installation practices than most other manufacturers, even though it is excluded under their terms and conditions.

Worcester Bosch boilers, in our opinion, are made relatively cheaply. Although they are far from the worst, we would put their build quality in the middle of the deck compared to what is currently available. All of their current boilers to date use aluminium heat exchangers, of which there are significant negatives for the consumer for these compared to stainless steel heat exchangers for example. More information about this can be found by clicking here. 

The majority of Worcester boilers use moulded plastics and rely heavily on o-rings and clips to hold the water-containing parts of the boiler together. In our experience, most of these plastics are brittle and are prone to fault as a result. Many current models have weak panel hinges that break easily, and some we find to be outright terrible to work on. In our opinion, given that these are one of the most expensive products on the market, the build quality does not reflect that. In every boiler type instance (combi, heat-only and system boiler), we believe there currently is a better built and less expensive alternative with other manufacturers. 

Worcester standard boiler guarantee is 5-years, which can be taken up to 6-years with the use of their filter. As of Oct 2018, until the end of the year and likely it will continue further, they have upped their guarantee to 7-years on the CDi range. Certain “approved” installers can currently offer you up to 10-years guarantee with Worcester Bosch boilers. To be able to provide these extended warranties, installation companies have to install minimum numbers of Worcester Bosch boilers and typically must install a Worcester Greenstar Filter. The advice being given to consumers on what boiler product is best for their home and situation could be tainted as approved installation companies decisions are likely to be influenced by the requirements specified by Worcester for them to maintain their “approved” status (meeting minimum boiler sales numbers for example) and the extended warranties they can offer to their customers as a result. Plus, other additional incentives the company/installer receives, such as cash-back and enhanced rewards programs for being a “loyal” installer are likely to influence what boiler products are specified to customers. As a result, most “approved” installers will only promote the Worcester brand to continue to get these enhanced benefits.

The latest range of boilers from Worcester Bosch are some of the worst build-quality boilers we have seen them produce. The new “Greenstar Compact” range, as shown above for example, in our opinion, has an inferior build quality compared to many boilers which are much cheaper to buy, and as a result, does not warrant its price tag in any shape or form in regards to build quality. In our experience, they are fiddly and very flimsy in parts, of which we are confident many other engineers who are being honest will share our view about this product line. Although it is one of Worcester Bosch’s cheaper domestic boiler products, it still is more expensive than most other models from other brands of a similar specification. 

The picture above shows the insides of one of the more premium domestic Worcester Bosch combi boilers, the Worcester Greenstar CDi Classic Combi. We have yet to see a boiler on the market that does not use o-rings and clips for joints of water containing components, but in our experience, the more of these you have, the more likely you are to have leaks. All current Worcester Bosch boilers we have worked on/seen rely heavily on these types of connections, with exception to some of their heat-only products which have far fewer components due to a more simplistic design.  

Above is the same boiler from a service we were undertaking. The condensate trap has been removed so you can see the internal connections better. You should be able to see copper connection tubes connecting into moulded plastic “water blocks/sections” which are used to transport water indicated by the red “A”.

In our opinion, the more water containing parts you have that are plastic, the more likely you are to have leaks in the future as plastics are generally far less robust in this regard when compared to metals such as brass. Plastics come in different grades and thicknesses, granted these in the photograph are not the worst plastic grades we have come across, but in our opinion, they like the others we have found in Worcester Bosch products in recent years are not high-grade composite plastics and we have had to replace these parts on numerous occasions due to them failing. This is not unique to Worcester Bosch, as many other manufacturers use similar or worse grades of plastic in a similar fashion, but we do want to show how we believe you can save money over the long term by using boilers that use more robust materials, which can result in fewer repairs and a boiler that needs replacing less often. This is one of the most expensive boilers on the market and we do not believe the build quality warrants the cost of the product. 

As with other makes and models, water containing plastic parts fail with splits, fractures and total breaks due to such things as mains water pressure (often within manufactures specified tolerances) and due to the plastic walls failing from regular heating and cooling, which is a common in hot water and heating production.

Above and from the same boiler, you will see probably one of the better-made aluminium heat exchangers on the market. However, this particular boiler we have witnessed on many occasions the heat exchanger splitting or corroding through in less than 12 years from installation, despite it being one of the better quality aluminium heat exchangers. Admittedly, where these have corroded through, it has mostly been due to poor installation/maintenance practices from when the systems have been installed and/or worked on, but we have still replaced a significant number of these boilers, or repaired at great expense, due to the heat engine failing were heating system water quality was not an issue. More information about heating system water contamination and its effects on aluminium heat exchangers can be found by clicking here and by also looking at the infographic below.

The Worcester Greenstar Cdi range uses are more robust connection method for its connection pipework onto the heat exchanger as indicated at point “A” above. This joint relies on a nut and washer to make the seal, which is far more resistant to corrosion from issues with the central heating water over a common alternative joining method which relies on an o-ring as pictured below from a boiler from another manufacturer. The reason for this is aluminium readily dissolves in acid. It will even do this in high-alkaline environments. Many of the products used to install central heating systems, such as fluxes and flushing chemicals, can have a negative impact on the heating systems PH (often leaving them more acidic), which will resort to aluminium heat exchangers corroding/dissolving away far more readily than what stainless steel would. In addition, soldering flux residues have been shown to form pitting within aluminium heat exchangers in a short space of time when not flushed from the heating system fully. With an O-ring connection as shown below (“A”), only a tiny bit of aluminium needs to be corroded away to create a leak, whereas the connection point shown on the Worcester Bosch Greenstar Cdi range needs a lot more corrosion to cause a problem. 

There are three main areas where aluminium heat exchangers fail, often resulting in a new boiler due to the cost to repair being uneconomical. The first is from the situation given previously where mild corrosion on an o-ring connection causes a leak. Another is where corrosion from the acids produced in the combustion process eventually corrode right through the heat exchanger, creating a water leak, pressure loss or a full breach. This will occur more quickly where contaminates within the heating system water, as per the infographic above, speed up the corrosion process of the aluminium heat exchanger. Sometimes this contamination can be the main reason for corrosion. The final way is where a fracture/split occurs. This often comes about from a boiler being operated with low system pressure or suffering with air trapped within the water containing part of the heat exchanger. In every instance, stainless steel heat exchangers are far more resistant to these faults. 

To be fair to Worcester, they do use better grades and thicknesses of aluminium than many other manufacturers, particularly in their Greens Star Cdi range. They may add such things as silicone to the metal compounds used to make their heat exchangers to make them more resistant to corrosion. However, in the real world, we have still seen many of these replaced prematurely due to splitting and system water corrosion of the heat exchanger despite these being better quality than others on the market. 

Issues that occur as a result of heating water quality are nearly always caused by poor installation or maintenance practices. Manufacturers are happy to pass the blame to the installer, of which it is fair to do so when they have not done the work correctly, but we believe they have their part in this as they could choose to use far more durable metals such as stainless steel or copper for example. Regardless of who is to blame, there are a widespread and common related issues from boilers that use aluminium heat exchangers which you can reduce your chances of suffering from such faults by using boilers made with stainless steel heat exchangers, especially when using a professional and high-quality installer to install and maintain your boiler and heating system. 

In the 1990’s and early 2000’s, Worcester made some outstanding boiler products, many of which still operate today. We very much doubt that the majority of the models, such as the ones above, being produced today will last anywhere near as long as the boilers from these eras. We also expect them to have increased repair/maintenance costs over their lifetime compared to older models also. 

In our opinion, at present and with all boiler types (combi, heat-only & system boilers), you can buy boilers for less money from other brands that have longer warranties and build qualities that should last many more years when correctly installed. Other brands now are rising to compete with Worcester on an aftersales basis, and some appear to be starting to outperform them. 


Vaillant Group, which own Vaillant, are one of, if not, the largest boiler manufacturers in the EU. Originally Vaillant was a German-based company that produced innovative products and some of the most robust boilers on record. Sadly, as with Worcester Bosch, this has changed and in our opinion took a turn overall in recent years.

Vaillant aftersales approach has upset a number of people we have met over the years, installers included. We have even had to make official complaints on behalf of customers were Vaillant engineers have attended and failed to honour the warranty within its terms and conditions.

At one time Vaillants aftersales nearly rivalled that of Worcester Bosch’s. However, over the last couple of years, how they treat their customers, in our opinion, can be poor. We have seen engineers apply call-out fees to customers and advise that the faults they are experiencing are excluded under the warranty they provide, yet either what they have advised to the consumer did not exist or was not specified in their warranty. We have known of other small to medium sized installation companies step away from Vaillant for similar reasons.

Vaillant does have a large dedicated team of engineers which undertake most of the warranty work. They do have a high first-time fix rate, although if a component has failed due to poor installation practices expect a callout charge and either expect them to refuse to do the work or quote in addition to replace what parts are faulty.

In the 1990’s and early 2000’s Vaillant made excellent boilers. Ignoring a few initial errors with their original designs, such as burner door seal material, their entire boiler range was full of well designed and robust products. However, just as with Worcester, we have found that the overall product quality is in decline. Part of this has to do with the multi-tier approach they have taken to their products. Now they offer entry-level products which are aluminium heat exchangers with plastic components, they then have middle range products which are stainless steel heat exchangers with plastic components and then they upper range products which are stainless steel heat exchangers with brass components and a premium product which is similar to the upper range product but boasts better efficiencies.

In our opinion aspects of the upper to premium, ranges are less robust than other better-priced alternatives, but their upper tiered boilers are still one of the better-made products on the market at present. However, when you look at the whole picture, there are more economical options available to you that are built just as well. An example here would be comparing an EcoTec Plus to a Baxi 600 Series. Both have equal warranties of 7-years and we believe they are similar in their build quality, but the Vaillant version is around £450.00 more to buy on average! When compared to boilers like the Baxi Platinum or Duo-Tec, Viessman Vitodens 100W Combi, Ideal Vogue Max Combi, there is a whole lot more of a better deal to be had when cost, build quality and warranty are factored in, plus we would say some of these examples are likely to be more reliable and cost you less in maintenance when correctly installed. The Vaillant does have a better control system than most, but in reality, to the average household, it offers very little more. If high-end control and specification were required, then the Viessmann Vitodens 200W is hard to beat. Some Vaillant models can be extended to a 10-year warranty with their protection kit, which costs around £150.00 to buy, plus whatever the installer will charge you to fit (if anything).

Above is a Vaillant EcoTec Plus Combi boiler. It still relies on O-rings and clips, but to a lesser extent than what the Worcester Bosch Combi boilers do. However, the cheaper range of products from Vaillant can be grossly different. The boiler its self is pretty robust by modern standards so long as it is installed correctly and maintained, although the diverter valves are prone to leaking and are known as a common fault. The door seals, although much improved from older versions, still need to be inspected on a regular basis as extensive damage has occurred in the past with older models where these have failed. 

In our opinion, due to Vaillant products costs, our past experiences and that what has been reported to us from others in regards to aftersales, we believe you can get better value for money elsewhere at present and better service. Two websites to compare boiler prices are MrCentralHeating.co.uk & PlumbNation.co.uk

Glow Worm

Are owned by the Vaillant Group, but initially originated from the UK.

Glow Worm are considered the ‘budget’ arm of the Vaillant Group in the UK. Their products are generally cheaper, but as with the Vaillants, we believe there are much better value deals to be had at present. In our opinion, it is possible to get a much better-made boiler for less money in many instances. They currently do not produce any boilers with stainless steel heat exchangers, their whole range uses aluminium. 

The warranty ranges from 2-7 years as standard when fitted by a “Club-Energy” installer which is an uncomplicated and easy to join scheme for installers. Where the warranty scheme differs from Vaillant is that Glow Worm allow you to upgrade the warranty length up to several years by paying, which in our opinion allows a lot more flexibility. The Vaillant engineer team upholds warranty repairs, so expect a similar warranty service, except as Vaillant is the ‘premium’ brand, it may be that Vaillant boiler owners get preferential treatment in busy times. 

We used to fit some Glow Worm products up to a couple of years ago. They used to produce a very robust, reliable and well priced heat-only boiler with a stainless steel heat exchanger. However, since the decline with Vaillant’s aftercare service and the new range of boilers, which happened at a similar time, we no longer recommend any of their products.


Baxi is part of the BDR Therma which is a large European manufacturer which Baxi initially began in the UK in 1866. They have a history of engineering innovations. In terms of their product quality, they have a mixed range, some of which we find are terrible, others we think are some of the best quality and value boilers on the market today.

Trustpilot reviews are not as good as they are with Worcester or Vaillant, but in our experience, the response time from “Heat Team” which handle the warranty repairs, are similar to Vaillant and not far behind Worcester Bosch (excluding the recently reported decline in service). Heat Team also has a large team of very well stocked and trained engineers, and in our experience, are more likely to replace a part under their warranty that has become defective due to poor installation practices than most other manufacturers.

For Baxi, as with other manufacturers, you will see complaints from people having to wait a week or less for an engineer in the middle of winter to attend a boiler under warranty. This can make up a significant portion of manufactures negative reviews on sites such as Trustpilot, which I feel is unjust. Yes, waiting a week without heating and hot water in the winter is not ideal, but the industry only has a limited number of engineers and the work volume is highly seasonal. Whoever you call can leave you waiting, ourselves can have several months of waiting times in the autumn and winter, let alone a week. As a general rule, we cannot provide breakdown repair services at this time of year in most cases. Where we believe Baxi go wrong with their reputation is they have managed to make some excellent products which are better built, have better warranties and cost less than that from most other manufacturers with some models, but then they taint this with poorly made products and as Trustpilot will show, some bad customer service.

Baxi offers a no-nonsense warranty scheme. Their warranties are the same for Gas Safe installers so long as they are registered correctly through their easy to sign up “Works” program. Unlike many other manufacturers, you do not have to fit additional filters or protection kits or fit a certain number of boilers to receive their warranties. If it says 10-years, it is, within the terms and conditions they set.

When it comes to combi boilers, Baxi has some of the best choices on the market if you want a robust product with a good warranty at a competitive price. The original Baxi Platinum (top above image), in our opinion, is possibly one of the best combi boilers ever built. The newest version (top below image) is slightly less robust around the pump area, but still hard to beat compared with what is available.  It has over a 14-year track record, is grossly cheaper than Worcester and Vaillant’s premium ranges, currently has a 10- year warranty and is built robustly. The photograph below is the lower part of the boiler (older version) which is obscured in the photograph above. As you can see, compared to over examples we have shown, there is a stark contrast in the materials used to make a boiler. The main difference in the new version is the type of pump used to meet current energy standards and the material of the automatic air vent (plastic), which can be seen in the above image. The latest version benefits from an improved filling mechanism. 

There is also the Duo-Tec, which is the same boiler which costs less, but a lower warranty (7-years) and then the Baxi 600 series, which could be argued as the best overall compact boiler on the market when price, build quality and warranty (7-years) are considered, although we prefer the Platinum and Duo-Tec build quality. Other combi boiler models from Baxi we do not advise. These three should cover all situations, plus the Platinum and Duo-Tec build quality, so long as correctly installed and maintained, is likely to last longer than most of the boilers on the market place. 

Baxi also makes a fantastic system boiler known as the Baxi Megaflo which is a great contender in the system boiler market, when all factors are considered (price, warranty, build quality etc), of which we would argue is one of the best deals overall.

We do not recommend any of the current heat-only boilers from Baxi at present. If the rumours of the 600 series producing a heat-only boiler are true, then this may change depending on what they produce, but in our opinion, currently, you can get a much better heat-only product from other manufacturers.


BDR Therma also owns Potterton, again initially originated from the UK.

Most Potterton products are very similar to Baxi but generally cheaper and with lower warranties. Builders and renovators commonly use their products as a result of this.  They have products that are very similar to the Baxi products we recommend, but if you are a home-owner, the Baxi products usually work out to be a better deal overall due to the warranties they currently supply. For the renovator or home builder, looking to reduce costs but still provide a well-built boiler, then the Potterton Gold, Promax Combi and Promax System are good low-cost contenders. Again we would not recommend any of their heat-only products. 

The BDR Therma Heat Team upholds warranty repairs, so expect a similar warranty service to Baxi. 


Ideal boilers were founded in 1906 in England, but now are part of Groupe Atlantic. 

Ideal’s aftersales approach has upset some people we have met over recent years, installers included. The main office has been reported to be difficult to deal with and there have been numerous reports to us of warranty visits resulting in charges to the customer which could be argued to be unfair.  To-date we do not have any first-hand negative experiences with their warranty service, but the installation of their products makes up a small part of our boiler installations over the years, so we have less experience with dealing with them than other brands. Our limited dealings with their office have not been smooth. For example, it took three communications and one complaint before the company had our local representative contact us about their current approved installer scheme. Trustpilot, and other internet sources can be checked to see what other people have said about the company and their products so you can come to your own conclusions better. 

Ideal does have a large dedicated team of engineers which undertake most of their warranty work. They are reported to have a high first-time fix rate, which is common amongst the brands with in-house warranty teams. Although, if a component has failed due to poor installation practices or any other excluded reason, from what we have been told, expect a callout charge. 

In regards to their products, they do have some competitively priced products on the market at present, especially in their Max Range which is offering market-leading warranties of up to 12-years. Recent changes to the Vogue and Logic range has seen the build quality of these products reduce in our opinion. We believe the original Ideal Vogue range, of which is not that old, was a  better-made product, but time will tell. A good review showing the build quality of the original Vogue combi, by an engineer called Allen Hart, can be found here, who also raises points about aspects being changed. For comparative reasons, we have put an image of the latest model below. In the new version, they have replaced high-quality brass components with plastic components, although from close examination they do seem to be of a high-quality and the same as in the Viessmann range.

What makes the current range of Ideal boilers competitive is their cost and the warranties they now offer, in particular, the Ideal Vogue Max System boiler. Although we believe the current version of the boiler is not as well built as the Baxi Megaflo for example, the additional 5-year warranty, or 3 years on the regular Vogue, for not much more money, is a big advantage and will take preference for some people. The chance of this being a cheaper boiler to maintain compared to the Megaflo is increased due to the warranty.  The Vogue System boiler (pictured below) certainly could be considered as one of the better system boiler packages on the market when all factors are considered compared to what is currently available.  In regards to the Vogue MAX combi versions, we would still recommend the Baxi Platinum or Viessmann Vitodens 100-W (with extended warranty) presently over this product, despite having 2-year less warranty as the build quality on both of these boilers are better. 

Currently Vogue Max boilers only come with 12-year warranties for “Max” accredited installers. At present this in an invite-only scheme, limiting the number of installers you can use. 

Our main gripe with the MAX ranges build quality is the plastic front case, which has plastic hinges, and the plastic water sections (especially that of the combi versions), although other issues may exist that need time to show. 

The Ideal Logic, Logic+ and Logic Max boiler range make up the main bulk of Ideals current products. Some of these are popular with home builders and renovators due to their price and warranty terms. These boilers all rely on an aluminium heat exchanger, of which we do not recommend where possible, but compared to other choices on the market which have these types of heat exchangers, these are competitively priced, hence why they are popular products. If we had to pick from all the aluminium heat-only products currently available for a heat-only boiler, then the Ideal Logic MAX heat is a hard package to beat with its 10-year warranty. However, Viessmann’s heat-only boiler is our current best recommendation as its build quality, in our opinion, is far superior to anything else on the market, who can deliver the after sales we expect for our customers. 


Viessmann are a German-based company who are market leaders in that country and have done since 1917. Although a large international manufacturer of heating and cooling products, in the UK, from what figures we have seen, they manufacturer a little under 3% of all the current UK boilers. Please note, the UK boiler market is reported to be larger than the boiler market of the entire EU combined. 

As there are not large numbers of Viessmann boiler out on the marketplace compared to the other brands already mentioned, it is hard to give a fair comparison when talking about Viessmann reputation from customers, people in the trade and other sources. Plus, how reliable and sturdy their products are is also hard to determine because we do not see them out in the field often. 

What we will say is that our dealings with Viessman thus far in recent times have been nothing short of excellent. From contacting the company, to their technical advice, the technical expertise they have given to us and the company’s general ethos seems to be nothing short of outstanding, which is refreshing. 

Viessmann has their own team of in-house engineers who undertake warranty repairs. Compared to the other brands mentioned, this team is much smaller, but it is reported that they have the best engineer to customer ratio when compared to all the other manufacturers, meaning that if this is true, they should have the lowest lead times on average for warranty related work. How well their engineers perform, what they are like to deal with and how fair they have yet to be established by ourselves, but the company certainly has the potential to be market leading with their aftersales. 

Viessmann can offer up to 10-year warranties. They have lower warranties for non-accredited installers as standard, with accredited installers having the option to extend their enhanced warranties of 5 and 7-years, model dependent, to 10-years by a form of a one-off payment. To become a Viessmann installer is not complicated, the required company/engineer(s) must attend a training course which Viessmann provide from their headquarters in Telford. 

Viessmann appears to be on the forefront of heating system design and engineering. In Germany, where gas prices are much higher than they are in the UK, they have developed technologies in boilers which push energy efficiencies well beyond what most of the boilers we use here are capable of achieving. In typical German fashion, aspects of their boilers appear to be engineered to a higher standard. 

Below you will see two sections of a stainless steel heat exchanger. The one on the left is commonly found in many boilers made with stainless steel heat exchangers in the UK, which we favour over aluminium heat exchangers for its durability. To the right of this, you will see the Viessmann version which they manufacturer themselves. There are apparent differences, which will reduce faults from blockages and restrictions, but Viessmann claims that the steel in their product is also superior. They boast that they have yet to have one of their heat exchangers fail/break worldwide since they have been producing them. 

Below is a full heat exchanger coil and it as a complete heat exchanger as it would be inside a boiler. It is very high quality, although we would prefer a nut and thread connected opposed to an o-ring that has been used. 

Some of the stainless steel heat exchangers in boilers on the market, as shown below, have an outer shell that is plastic. The problem with this is that if they overheat, as they expand at different rates, the plastic outer shell versions can split/fail, whereas the Viessmann version, and some others on the market that use stainless steel for the outer shell, do not suffer from the same problem, thus making them more durable in theory.  Some boilers manufactures install a fuse in these plastic shelled stainless steel heat exchangers so if they do overheat and burn out the temperature fuse, the boiler will not work until the heat exchanger is replaced. 

In our opinion, this aspect of the Viessmann boilers, which is used in their entire current boiler range, is market leading. Given the cost which is associated with replacing a component like this on any boiler, which often leads to a new boiler being required when it does as a result, it would be beneficial in investing in a boiler with this sort of quality in its design.

The Viessmann Open Vent boiler, which is a heat-only boiler type, is our most favourable heat only boiler for recommendation on the market at present based on its build quality, which we have provided a picture below. As with all of its range, most aspects of the boiler are high quality in their build.

Their Vitodens 100-W combi boiler below is also a good boiler, although we would prefer brass water containing components over what they have opted to use. To be fair to Viessmann, the water containing part of this boiler is a complete singular block which is made out of plastic material which appears to be far more high-quality than the other examples you have been shown. It is of a thick-walled construction and feels very sturdy, plus as it is a complete block, there are far less o-ring washers used than some other alternatives, reducing the chances of leaks. As we have come across few of these, we cannot compare the durability of this to other boilers we are familiar with, but based on the feel of this boiler, so long as it is correctly installed and maintained, the major and more expensive parts potentially could last a very long time. If we were to speculate, this boiler does have the potential to outlive the likes of the Baxi Platinum and maybe last 20+ years without extensive repairs. 


Atag, which have commercial boiler routes, have recently started to produce boilers for the domestic UK boiler market in the last couple of years. They have been producing boilers for over 70 years, but their domestic arm has only been set up in the last couple of years. 

Although they are far from a major supplier, they do produce what appear to be excellently well-made products on their current domestic boiler range, which could possibly be some of the best-made boilers on the UK market, hence why we have mentioned them, as if you have not realised by now, we are a big believer in boiler product build quality.

Our issues with Agag are the lack of trading history, the high-risk factors of the company failing and leaving customers possibly unable repair their products in the future as a result, their lack of experience in the domestic sector and their current trading methods. 

Atag does not have a dedicated team of engineers to attend to their boilers under warranty. Instead, they use “partners” which in addition to this they currently restrict the sales of their boilers and spare parts to. So what this means is under a warranty call-out situation, the customer will have to rely on private businesses which are separate from Atag to repair their boiler. This likely means that in most cases you will have an engineer attend with a limited stock of parts and far less experience at fixing that particular boiler than what a dedicated in-house engineer would have. As a result, we would expect this to have an adverse effect on how long a warranty call-out could take to resolve. Atag has advised us that the area manager will attend warranty jobs where they cannot provide a partner in a reasonable amount of time or at all. How well this works, we cannot say. 

Only Atag partners can buy their products or spare parts, meaning that there is a much more limited number of engineers/companies that are part of their partner scheme who can install you a boiler of theirs or fix it outside of warranty. This could mean once your warranty runs out you could be without heating a long time waiting for an engineer to attend, plus some companies/individuals out there could take advantage of this and charge highly for their services as there is less competition. Also, as there is no competition from merchants to drive wholesale prices down, or really anywhere to check the prices of their boilers, you have no real idea what your installer could be charging you for the boiler compared to the total installation price.  Atag advised us that they will not sell their boilers direct to our customers even if the customer wanted to pay for the boiler directly. 

As we have never worked on one of their products to-date, all of the increased risks of it being a new company (domestic division), the rumours into how the domestic company has been structured (which we cannot confirm) and lack of the aftersales we expect from a boiler manufacturer, we would not install these boilers at present.

We are interested to see how Atag move forward in the years to come and hopefully they will grow into a company that produce excellent products that we can work with. On a plus note, from what we have seen of their boilers made to-date, they do look very well made.