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Worst! Boiler Brands to Avoid (2024)

brands to avoid

Worst Boiler Brands

The worst boiler brands currently on sale in the UK are:

  1. Ferroli Boilers
  2. Vokera Boilers
  3. Keston Boilers
  4. Biasi Boilers

In this article, we will give you the full run down as to why each of these brands should remain far off your radar when choosing a new boiler, but first, we’ll tell you how we worked out the worst of the worst.

How We Judge the Worst Boiler Brands

To identify the worst offenders and create an unbiased and comprehensive evaluation of the worst boiler brands of 2023, we’ve amalgamated a wide array of factors. 

These factors include:

Which? Annual Boiler Survey Results

This is a critical component, as Which? is a trusted UK organisation known for thorough product and service testing. 

They most recently surveyed over 12,000 boiler owners and 166 heating engineers, combining user experiences with expert opinions. 

The survey assesses various aspects such as reliability, customer satisfaction, engineer recommendations, build quality, availability of parts, ease of fixing faults, and ease of servicing.

Brand Reputation and Customer Reviews

The overall reputation of the boiler brands, as reflected in customer reviews, plays a significant role. 

This includes analysis of both generic customer reviews and specific platforms like TrustPilot.

Warranty Period

The length and comprehensiveness of the warranty offered by the brand are considered indicators of the manufacturer’s confidence in their product.

Awards and Accolades

Recognition in the industry, such as Which? Best Buy Awards are taken into account to assess the quality and performance of the boilers.

Customer Service Performance

How well a brand handles customer queries, complaints, and service requests is a crucial factor.

Price Range

The cost of the boilers is considered, providing insight into their value for money.

Efficiency Ratings

The energy efficiency of the boilers is also a key factor in their evaluation.

This comprehensive approach ensures an objective comparison, relying heavily on data and real-world experiences rather than subjective opinions or potential biases.

The culmination of these factors provides what we feel is a fair, robust framework for identifying the worst boiler brands, based on both technical specifications and real-world user experiences.

So, with no further ado, we give you…

The Worst Boiler Brands to Avoid (UK)

Ferroli Boilers

ferroli boiles


Founded in the 1950s, Ferroli is an Italian company that has established a significant presence in the European heating market over the past 8 decades.

Ferroli’s range of products typically includes various types of boilers, including combi, system, and regular boilers, designed to suit different household needs.

Reasons to be Avoided

The reasons you should welcome a Ferroli boiler into your home with all the enthusiasm you would show a starving grizzly bear that has just been poked with a particularly spiky stick are both compelling and numerous. 

The most common complaints about Ferroli boilers include 

  • frequent failures (boiler not providing hot water when the central heating is turned on, loud clunky banging noises, frozen condensate pipes, low boiler pressure, leaks from the bottom of the boiler, and heating not working properly)
  • issues with the warranty, service, and product quality


  • Which? Survey Results for Ferroli boilers in 2023 indicate an owner satisfaction score of just 68%, earning it a three-star rating 
  • The brand received a below-average customer score of 68%
  • The reliability tests rated the boiler at 3 out of 5 stars, and engineers rated the manufacturer at 1 out of 5 

These scores contribute to Ferroli’s overall rating, which is significantly lower than the majority of other boiler brands, indicating a below-average performance compared to its competitors.

Vokera Boilers

vokera boilers


Vokera, part of the Riello Group, is a well-established boiler manufacturer known for its range of heating products. 

Their product line includes boilers, renewables, and unvented cylinders, catering to both residential and commercial needs.

Reasons to be Avoided

Vokera as a brand has a number of recurring complaints about their boilers which includes

  • Frequent breakdowns due to low-quality Italian components, leading to reliability issues
  • Short warranty period, typically no more than 2 years, indicating potential longevity concerns
  • Lack of parts and slow delivery of available parts, leading to difficulties in repairs and high costs
  • Inefficient customer support and inadequate water heating, especially in winter due to condensation


  • Which? Survey Results for Vokera boilers in 2023 indicate an owner satisfaction score of 67%, earning it a three-star rating 
  • The brand received a below-average customer score of 69%
  • The brand received a below-average customer score, and only 69% of owners gave them 5 stars, while 9% rated the company as ‘Bad’

Vokera came in second to last with an overall score of 50% in the Which? survey, indicating a below-average performance compared to other boiler brands

Keston Boilers

keston boilers


Keston Boilers, a British manufacturer founded in 1928, is recognized for its production of heating solutions in both residential and light commercial markets. 

Acquired by Groupe Atlantic in 2006, the company moved to a state-of-the-art manufacturing facility in Hull in 2013, where it continues to innovate and produce its various combi, system, and heat-only boilers.

Reasons to be Avoided

The most common complaints about Keston boilers include:

  • Frequent Faults and Issues: Owners have reported frequent problems with Keston boilers, such as low water pressure, error codes related to water pressure, and issues with the flame, fan, and ignition
  • Reliability Concerns: Some users have experienced persistent issues with their Keston boilers, leading to a lack of reliability and the need for frequent resets and contact with installers
  • Low Water Pressure: Error codes such as F1/E44 and E67 indicate low water pressure, which can lead to heating and hot water issues
  • Complex Error Codes: The boiler’s error code system has been reported as complex, requiring homeowners to troubleshoot and potentially seek professional assistance for resolution


  • Which? Survey Results for Keston boilers in 2023 indicate an owner satisfaction score of 47%
  • 79% reported issues with performance within the first four years

This places Keston as the lowest-ranking boiler manufacturer in terms of customer satisfaction, reflecting a significant level of dissatisfaction with the brand’s products.

Biasi Boilers

biasi boilers


Biasi UK Ltd, established in 1990, is a leading supplier to the British heating industry, operating from a 64,000 sq ft facility in Walsall, Midlands. 

The company offers a comprehensive range of heating solutions, including residential boilers, central heating radiators, towel rails, and LST radiators.

Reasons to be Avoided

The most common complaints about Keston boilers include:

  • Ignition Issues: Some users have reported problems with the boiler failing to ignite, which can lead to a lack of heating and hot water
  • No Hot Water: Another frequent complaint is the lack of hot water, which can be attributed to issues with the diverter valve
  • Water Pressure Problems: Users have experienced issues with low water pressure, leading to heating and hot water issues
  • Banging Noises: Some boilers have been reported to make loud banging noises, indicating potential operational issues
  • General Boiler Lockout: This is a common issue that can be caused by various underlying problems, leading to a complete shutdown of the boiler


  • Which? Survey Results for Biasi boilers in 2023 indicate an owner satisfaction score of 68% earning it a three-star rating
  • Biasi has the joint worst score in the survey
  • 10% of customers deeply regretted their purchase of a Biasi Boiler

With the joint worst customer satisfaction scores and frequently recorded reliability issues Biasi remains a boiler brand best left well alone.

Frequently Asked Questions (FAQs)

Which boiler is most reliable?

The most reliable boiler brands in the UK, according to various sources, include:

  1. Viessmann
  2. Worcester Bosch
  3. Vaillant
  4. Alpha
  5. Ideal

These brands are well-regarded for their reliability, efficiency, and overall performance, making them popular choices for homeowners looking for a dependable heating system

Is it still worth getting a combi boiler?

Absolutely! Combi boilers are generally the most efficient, affordable, reliable and suitable types of boilers for the modern UK home. Which isn’t to say you must get a combi boiler – as other kinds of boiler might be better suited to your particular requirements or preferences.

What are some oil boiler brands to avoid?

EOGB/Sapphire, Grant, Firebir, and Warmflow are all well-known manufacturers of oil boilers in the UK.

If we had to pick one brand to avoid it would be the South Korean brand Navien, whose boilers tend to be less sophisticated and reliable than the brands mentioned above.

Boiling it all Down

So, there we have it. 

Our extensive evaluation, grounded in data from the Which? Annual Boiler Survey and other customer reviews from multiple sources, highlights the worst boiler brands to avoid in the UK for 2024. 

These include Ferroli, Vokera, Keston, and Biasi Boilers, all of which have faced substantial criticisms for frequent failures, warranty issues, and poor customer service performance.

However, if you are interested in finding a great boiler to replace your old one, you can find a great replacement boiler from some of the leading boiler manufacturers right now.

Boiler Choice Director & Founder

This blog was written in collaboration with Eddie Scoffin, the founder of Boiler Choice. Eddie has been installing boilers for over a decade. With a passion for excellence and customer satisfaction, Eddie’s leadership and expertise have been instrumental in the success of Boiler Choice. His commitment to making the boiler installation process hassle-free for customers has earned him a respected reputation in the industry.

Updated on January 05, 2024