The Boiler Survey Report 2019

This entry was posted on 10 April 2019.

You spoke – we listened, find out WHICH BOILER IS BEST!

You had your say, and the results are in! Over 800 of our customers – plumbing and heating engineers – took part in our National Boiler Survey at the end of last year.

From Best Value to Build Quality, we’ve got the results of YOUR opinions.

Paul Jepson, our very own Boiler Guru has gone through the lot (with a very strong cup of coffee) and prepared the objective results, click HERE for your own version, or read on. Agree with our report?  Hit

Installer’s voice – the national domestic gas boiler survey 2019

What have over 700 engineers got to say about the boilers they work on every day?


Having been guilty on many occasions of ‘getting the popcorn out’ when a debate arose on social media as to which is the best boiler, we decided to run a comprehensive survey covering all aspects of boiler installations to see if we could come to a consensus as to which domestic gas boiler is the best on the market today.

Williams & Co launched this survey in October 2018. There were some initial qualifying questions (how many boilers do you fit, how much influence do you have and so on). The survey was in 5 sections, with questions about the manufacturers support and service, including technical helplines. There are then in-depth questions about combis, regular and system boilers. In these sections, respondents were asked their opinions about ease of installation, build quality, how easy the boiler was to service and some further questions about spares.

The engineers had to have worked on the boiler over the last 12 months. These questions included asking the engineers which branch of boiler would they recommend if one of their nearest and dearest was having one installed. There were 3 categories for this: Small budget, medium budget and a money no object budget. A final question asked what they would say to the MD of a manufacturer if they had his ear.

These are the findings, with over 700 verified Gas Safe Registered engineers giving freely of their expertise and insights from working on them.

Compared to our previous survey (2017/2018) there has been an encouraging change in the amount of boilers that engineers have installed over the past 12 months, with fewer installs between the 5-10 mark (was 24% now 21%). The ground was mainly gained in the 11-25 range, from 36% to 40% of installers enjoying an uplift in new installs. The higher and lower tiers remain relatively unchanged, with a slight increase in the 26-50 range which rose by 1%.

It would appear that the respondents have also increased their ability to install the boilers of their choice, with fewer engineers saying they only have some influence (20% in 2017/2018, down to 17%) and more having a strong influence (up from 50% to 53%) and a 1% increase in those who said they had complete control. Those who had no influence remains unchanged at 2% of all respondents fitting what the customer specifies or their company provides.

The trend of ‘more’ is continued in the repairs and servicing arena, with less engineers repairing/servicing under 100 boilers per annum, 5% less overall with those 5% now maintaining greater than 100 boilers a year.

Scores for presales literature and advice have fallen this year, although Worcester and Vaillant maintain the top spots. Atag make an appearance for the first time shooting straight into 3rd spot. In the last survey, we couldn’t include this manufacturer as there weren’t enough respondents who had worked on them to qualify.

Atag make an entrance this year straight in at the top spot for their after sales support. This would include warranty call outs and representative’s assistance. Most manufacturer’s scores dropped compared to the last survey, with some exceptions (Keston, Heatline and Baxi) who increased their after sales score by 3%, 3% and 2% respectively.

Worcester remain at the top for their technical helplines scoring 75%, up 1% from the previous survey. Vaillant hold on to second place, although their score was down 5% from 72% to 67%, with Baxi marginally behind. Ideal and Atag are the only other two manufacturers scoring above 60% with noticeable drop offs in scoring as we work down the list.

The respondents were given an opportunity to express their thoughts on technical helplines. A common theme that occurred was the time it took to respond to a call. This was the same in the previous findings. Here are some of their comments:

“Don’t like paying premium phone rates.”

“Long wait times a big letdown”

“On hold for 40 mins to Baxi”

“Seems to depend on the individual tech support person. Some are very helpful. Others are incredibly patronising and unhelpful ‘know-it-all’ types who can’t grasp the fact that someone has rung for help”

“Sometimes very long time, no responsibility”

“Hard to get through to most of them and when you do it’s always the same old message”

“Telephone waiting times are excessive during peak heating periods”

“Sometimes it like pulling teeth trying to get a sensible knowledgeable answer.”

“Some manufacturers just push parts”

And then there’s always some contradicting experiences:

“Vaillant are the best”

“Valliant are easily the worst service. Try anything to get out of it”

“Vaillant take a long time to answer calls but advise is good”

 “Worcester take time to solve specific probs”

“Worcester-Bosch just had new system installed which is not good at the moment”

“Intergas are way ahead technically”

“Intergas help line has always been extremely efficient”

“Intergas tech isn’t the best, I can get better advice in the fb group.”

This section is the most hotly debated topic amongst engineers. We asked the respondents which brand of combi boiler they would recommend to a close relative who needed one installed. There were three budgets: small, medium or ‘money no object’. These are the results.

In the highly competitive entry level category, this year finds a wider spread of scores, with Heatline and Ravenheat leapfrogging Ideal and Main to take the top two spots this year. An incredibly tight category with the top 3 brands only separated by mere fractions of a percent, one could perhaps argue that they enjoy equal first place.

Positions at the top 8 for the medium budget haven’t changed since the last survey, with Ideal taking top place followed by Baxi and Glowworm, although Ideal lost 3% of their score from last year. Scores for Ideal last year were 17% compared to just over 14% this year, and Baxi increasing their score from 12% to 13%.

This year, although Worcester scored exactly the same as last year’s survey (25%), they take the title from Vaillant in the premium brand category. Vaillant dropped from 27% of installers recommending them if money was no object, down to 23%. Viessmann pinched the most of Vaillant’s recommendations, growing support from 10% up to 14%. Atag and Ideal remain 4rd and 5th with identical scores to last year, then Baxi take Intergas’ 2% lead from last year, making Baxi now the 6th most recommended boiler if money was no object.

Other points to note

We broke this down a little more by asking other questions on individual boilers that might back up these findings, or find out what aspects of the boiler the installer’s liked, bearing in mind again that installers had to have worked on the model to be able to voice their opinion and experience. The following categories were marked by our respondents from 1-5, and then converted into a percentage. The higher the percentage, the better the boiler in that category. With over 50 combi boilers on the market (at the time of survey), we’ve left out the those that didn’t have enough responses to avoid skewing data and illustrated the top 15 boilers.

This section in last year’s survey was dominated by Intergas and Vaillant (each having 3 models in the top ten), and the Ideal Vogue took the top position. This year the Ecotec plus range by Vaillant is number one for ease of installation, but with a lower score of 68% compared to last year’s score of 74%. Noticeably missing from this year’s top 15 are the Glowworm Energy, Baxi Ecoblue, Ideal Vogue and the Intergas Eco RF.

It’s all change again in terms of build quality compared to last year, with Viessmann not making the top ten after pinching the top spot last year. Intergas took 2nd, 3rd and 4th place last year, but have only managed one entry into the top placings with the Eco RF this year. The Vaillant Ecofit wasn’t around in last year’s survey but takes first place this year. Ideal crept up the rankings with their Vogue Gen 2 offering, moving from 5th place with their pre-ERP Vogue to take 2nd place this year. Atag make their first entrance into the rankings this year, as previously there weren’t enough respondents who had worked on them to include the data.

In terms of ease of servicing, Intergas once again take the top two spots, although the HRE was first last year. Interestingly their scores increased massively, with the ECO RF increasing their score from 74% last year to a whopping 89% this year. The Vogue from Ideal also had a huge increase in score, moving from 58% to 84%. Again Atag make an appearance and take 4th place for their ease to service.

For the availability of spares, Worcester have all four of their combi models in the top ten and pinch the top spot from Baxi. Interestingly, it’s Worcester, Baxi (inc Main & Potterton), Vaillant and Ideal who dominate the top fifteen with no other manufacturer making it in this year.

A much commented on section, spares are generally seen as overpriced. This is reflected in the scores with Intergas the only brand to score over 70%. The median score for this section is 57%.

“…spare parts should be much better priced to support their own products.  One maker has a retail of £560 for a PCB, on that basis alone I’ll never fit one of their boilers.”

“Glow-worm, reduce spares prices”

“boiler MUST be easy to repair with moderate priced spares.”

“I would recommend to Vaillant to go back to better quality parts. I feel as though the parts are very expensive for quite poor quality products.”

“Make spares more competitive with regards to the price of a boiler. ie- boiler costs £900, fan £230…”

“Why are the spares so expensive – at the moment it is more cost effective sometimes to replace the boiler rather than repair – which is not very environmentally friendly!”

For overall value for money, Atag take first place with their iC economiser range of combi, narrowly pipping the Intergas ECO RF by 1%. Intergas are the only manufacturer to have three of their ranges in the top ten (the Xtreme was not included in the findings due to insufficient data). Baxi also did well with their three ranges all making the top fifteen, Ideal also took three placings. Viessmann and Vaillant managed two placings, Glowworm only placed one of their five ranges. No sign of Worcester Bosch in the top fifteen, in fact they didn’t even make a top twenty position in the combi boiler category for overall value for money, but scored the highest in the ‘installer recommendations if money was no object’ section. Intergas, Ideal and Baxi scored well here, and that is reflected in the other two installer recommendations sections, with Ideal taking top spot for a medium budget, followed by Baxi, Glowworm and Intergas.

Ravenheat take the top spot again with a fraction over 11% of respondents recommending the brand for small budgets, this time in the Heat Only category, pinching the title from Main who were last year’s leader. Glowworm and Ariston maintain 3rd and 4th position respectively, with Ideal dropping from 2nd place last year to 5th this year, losing 4% of votes (13% down to 9%).

The top two positions in the medium budget category are unchanged other than the percentages scored. Baxi made some gain on Ideal, scoring a shade off 14% compared to 11% last year, with Ideal Scoring 16% last year and 15% this year. Intergas improved their ranking with 11% of respondents rating them in this category, leap-frogging Glowworm and Vaillant. Scores for Viessmann, Worcester, Vaillant and Glowworm are only separated by fractions of a percent, with Vaillant and Worcester scoring similarly.

In this category, we would expect to see brands where perception is that they are a premium product, so it’s no surprise to see Worcester-Bosch, Vaillant and Viessmann scoring well in this section. This year, Worcester again took the top spot scoring 28%. Vaillant lost ground compared to last year scoring 24% this year compared to 28% last year. Viessmann made up almost a 5% increase, going from 9.6% to 14.3%. Atag maintain 4th place, Baxi and Ideal scored similarly with 7%. Intergas lost recommendations this year, dropping from 5th place last year (6%) to 7th place (4%).

For ease of installation, the Atag scores an impressive 94%, followed by the EcoFit range by Vaillant with a score of 90%. The Intergas HRE made 3rd place. Baxi scored well, with 3 of their ranges making the top ten. After the Baxi 200/400 range, 5 manufacturer’s offerings score exactly the same at 74%.

The Atagi R range scores a whopping 98% for build quality, improving on Intergas’s HRE score of 92%. Last year Intergas scored 93% and were first place with their HRE SB range. Baxi and Vaillant score highly too, with 88% and 87% respectively for the Baxi Ecoblue Advance and Vaillant’s EcoFit range. Viessmann were number 2 in the last survey but have now dropped to 5th for their build quality.

The Atag R is proving to be a highly rated boiler, again scoring 96% for ease of servicing, with the Vaillant EcoFit Pure bang on 90% in second place. Intergas lost some ground this year, dropping from a score of 93% to 84%. There is little drop off for the Viessmann 100-w, ideal Logic, Vaillant Ecotec plus, Baxi Ecoblue and Glowworm Energy ranges, all scoring around 80%.

Availability of spares is only separated by small percentages in the top ten, with the Worcester CDi Classic leading with a score of 85% and the Vaillant EcoFit Pure 84%.

Installers have scored this section relatively low, reflecting the scores in the combi boiler section. Atag once again take top spot, albeit with a score of 82%, the lowest score for any top spot in the heat only section. These results reflect the installer’s dissatisfaction with the pricing structure in the spares market, as seen in the comments section of combi boiler spares value for money.

In the overall value for money, we asked the engineers to consider all of the previous questions such as build quality and anything else they thought relevant, and to score the boiler overall. Atag take the top spot here, followed by the Intergas HRE. It’s curious though that out of the two, only Intergas made the top three in the boiler recommendations section in the medium budget. Baxi score well here, and they have high positions in the small and medium budget range.

This year the differences between the top five are mere fractions of a percent, with Ravenheat gaining the most votes (9%) in the small budget category for system boilers. Main  and Ideal take second and third respectively, with Main just gaining a small advantage over Ideal. Alpha gained some recommendations compared to last year, placing 5th this year over 7th last year.

Ideal maintain their first place in the medium budget range, with Baxi also keeping their second place. This year however, the margin between the two is significantly lower, with Ideal losing 2% (from 16% down to 14%) and Baxi gaining 1% from 13% to 14%. Intergas move up the rankings from 5th to 3rd place. Glowworm stay in 4th place and Worcester now in 5th. Vaillant lost ground this year, slipping down the rankings from 3rd place with a score of 11% down to just over 9%.

In the top end budget, Worcester-Bosch take the lead from Vaillant, taking 29% of recommendations from installers if money was no object. Vaillant lost 4% of recommendations in this category making them slip down to 2nd place. Viessmann maintain their 3rd place, Ideal swap places with Atag with a marginal difference.

Atag take top spot in terms f ease of install with there is system offering, followed closely by the Intergas HRE SB, Glowworm Energy and the Vaillant EcoFit Pure range enjoying equal 2nd place between them with a score of 88% each. Ideal’s Vogue slipped from 1st to 5th place, but only dropping their score by 2% from 83% to 81%. Baxi’s Ecoblue, Vaillant Ecotec Plus and the Viessmann 100-W all scored 78%.

For build quality, the Atag iS takes 1st place by quite a high margin, scoring 97% with the Intergas HRE SB the only other boiler to score over 90% in this section. After these two boilers, scores are similar in the top ten, ranging from 87% (Viessmann 200-W) to 84% (Worcester CDi classic).

For ease of servicing, the Atag and Intergas maintain their 1st and 2nd places respectively, again both scoring over 90%. Similarly, the top ten are only split by small increments, with the Main Eco Elite scoring 88% and the Ideal Independent scoring 83%, suggesting that these manufacturers system boilers are all relatively similar in terms of how easy they are to service and/or repair.

The top ten boilers for availability of spares are only separated by a total of 5%, with the Main Eco Elite scoring 88% down to the Vaillant Ecotec Plus (10th place) scoring 83%. Interestingly, Atag’s iS boiler is down in 18th place. What this means could be open to interpretation, but one theory could be that due to a confidence in their reliability, the brand’s manufacturing and distribution of spare parts isn’t high on their list.

Baxi’s Ecoblue and Viessmann’s 200-W range have the top placings in the category for spares value for money, although the highest score is 79%. This strengthens the argument that from an installer’s perspective, spare parts for boilers are too expensive when compared to the overall price of a boiler. The drop off from 1st place to 18th is again in small increments, so we could argue that across the board, spares are seen as not particularly good value for money.

In the final part of the system boiler survey, respondents were asked what the thought of the boiler in terms of overall value for money. Atag took top placing once again with a score of 94% and Intergas took 2nd place with a score of 91%.for the next six boilers, the drop off is relatively small with Glowworm, Viesssmann, Baxi, Vaillant and Ideal all scoring around the mid 80’s.

In comparison to the recommendations on various budgets, although Atag score highly in terms of day to day working with the boiler, they weren’t high on the list if recommendations, their highest placing being 5th in the ‘If money was no object’ category. Worcester scores were reasonably average in the day to day sections but scored 1st in the premium category of recommendations.

Vaillant and Viessmann made lots of placings in the different sections, and this is reflected by their 2nd and 3rd placings in the premium recommendations section.

Comments to the MD

In the final section of the survey, we asked engineers the following question: “If you had the ear of the MD for any boiler Manufacturer, which one would it be, and what 1 thing do you think they could do to improve their boilers?”

Common themes were returning to brass instead of plastic parts, improving quality and time to answer technical helplines, and price both for spares and the boiler itself. Here are some sample responses:

A better response from the tech line

All of them . Stop using plastic instead of metal. Use quality electronics. Adequate technical support/line

All other Technical support other than Viessmann And Worcester, massively need to improve their response time

Alpha need to reduce the price of their parts and include the associated washers in with the part

Any that use plumbing jigs for combis. I much prefer the connections like Ideal Logic and Vogue.

Ariston, spend more on marketing.

Ask them if they wanted their ear back? Because they don’t seem to value the independent gas engineers and will consistently undermine them.

ATAG,  Best boiler I’ve been involved with ever.   The only thing that needs to improve is the boiler connections to the jig, always find them difficult to connect.

Baxi  Make the wiring terminals bigger on the board. Make the PRV connection more accessible 600 range

Baxi and make literature more appealing to the consumer.

Baxi domestic build quality is very poor compared to Baxi commercial.

Baxi make them cheaper

Baxi, remove the permanently fixed cable to the Ecoblue Advance heat only. Vaillant: Create a boiler without generic issues and reduce the cost spares when these issues appear. Worcester: make a boiler for the installer not for yourself.

Could we make the boilers cheaper as it drives skilled people to charge more.

Fewer plastic components, easier to service.

Get rid of plastic parts and make all controls user friendly, Vaillant’s controls are a joke

Get rid of the plastic/composite.

Glowworm and Vaillant. Sort out your technical line and warranty.

Ideal – rethink their terrible warranty stances. Been stung a couple of times by their engineers on warranty callouts. Refuse to install any more of their products due to their poor back up

Ideal boilers, need to fit a connection on the safety valve discharge pipe ,or make it more accessible when the boiler is on the wall

Ideal boilers are very good. Shame they keep increasing their prices too often in last few years and some people are finding it hard to pay that sort of money.

Ideal boilers to put a better drain off on your boilers

Ideal price

Ideal prv connection could be easier

Intergas a very good build quality for the price. Very reliable.

Intergas  Make it easier for suppliers to get your products

Intergas better installer support 

Intergas. Get better support for installers and better parts distribution

It would be Worcester and would make a big improvement by making prv and expansion vessel much more accessible

Look at the new Ravenheat boiler on the market designed by an engineer, best boiler to work on by far   

Maintenance costs  seals etc

Make spares cheaper

Make them cheaper!

Position the parts that fail most frequently to be easily changed.

Price and the amount of different boilers

Price inc spares

Ravenheat – Make a new heat only boiler range – compact with no pump over run required. The range seriously needs it!

Ravenheat, I’d ask them to improve/upgrade their heat only boiler

Reduce price of spares

Sell appliances and spares to Gas Safe engineers only. And if you’re the Atag MD keep up the great work.

Spares cost and technical help

Stop using so many plastic parts. Have an Inbuilt carbon monoxide/gas leak detector that turns the boiler off when there is a fault, should be law, would save so many lives.

Technical helpline better communication skills

Use less plastic

Vaillant – customer service needs improvement, answer the phone much quicker for tech support and get a rep that returns calls.

Vaillant – sort out quality control and get rid of the silly isolation valves

Vaillant Improve after sales service

Vaillant Reduce the price of your spares

Vaillant: remain as a quality brand by not compromising on build quality (don’t manufacture Ecofit etc with cast aluminium heat exchangers), it has really lowered my opinion of the brand as a whole.

Vaillant; simpler installation and servicing instructions

Valliant To use as little plastic parts as possible

Viessmann  Best boilers  Need improvement on flue connection and controls need to be simpler

Viessmann boilers. I am an approved installer and I think they need to be more proactive in their advertising to promote their products as a lot of installers I speak to don’t really know enough about their boilers

Viessmann, provide a full service kit with all seals etc for the v100 combi.

Worcester – make their case edges safe and not razor sharp

Worcester – to improve on design for ease of maintenance and repair

Worcester: carry on!

Worcester boilers. Stop making boilers with so much plastic in them. Premium price, poor quality, plus stupid case fastening designs.

Worcester Bosch    Attempt to reduce the cost perhaps?

Worcester Bosch get rid of all the plastic and aluminium components.  To all boiler manufacturers can you please follow ATAG’s footsteps and only sell to gas safe registered installers.

Worcester Bosch, get rid of all the plastic components and change the heat exchanger material to stainless steel instead of aluminium

Worcester Great boiler great back up. Needs to be easier to service

Worcester, make a cheaper option boiler for rentals

Final thoughts

Although Worcester didn’t score highly across the board in the sections such as ease of install, ease of service etc. they swept the board in the ‘installer recommendations if money was no object’ polls. Drawing on the data, this could be based on the brand’s high street perception along with their high scores in pre-sales, and after sales service. After doing incredibly well in the last survey, Intergas dropped off in many aspects, whereas Atag made some good ground. Baxi and Ideal overall maintained a good showing, and Vaillant dropped a little overall, most notably in the recommendation sections. Viessmann scored overall better than last year although is still relatively unknown to householders in the wider domestic UK market.

About the survey

The survey was launched in September 2018 and closed in December 2018. Analysis took place in March 2019. Respondents were all gas safe registered.

Statistical Accuracy – Confidence and Error

1. Error – This is “plus or minus X%”. What it means is how confident we are that the results have an error of no more than X%.

2. Confidence – This is how confident we feel about the error level. Expressed as a percentage, it is the same as saying if we were to conduct the survey multiple times, how often would we expect to get similar results.

These two concepts work together to determine how accurate the survey results are. For example, if there is 90% confidence with an error of 4%, that’s saying that if we were to conduct the same survey 100 times, the results would be within +/- 4% of the first time the survey was run, 90 times out of 100. For this survey, we ran at +/-4 at a 95% confidence level.

About the author

Paul Jepson has 17 years of experience as a Merchant, 11 of those as an employee of Williams & Co, an award winning, independent trade-only plumbing and heating merchant with 36 branches in Hampshire, Surrey, Sussex, Kent, Berkshire, Essex, Buckinghamshire, Greater Manchester and Greater London.