James Elston

Published April 9, 2024

While boiler replacement can feel daunting, navigating the market doesn’t have to be stressful. No matter your budget or space constraints, there are a variety of excellent modern boilers to choose from in the UK.

Some invaluable tools to use in your decision-making process are:

  • Customer reviews
  • Qualified engineer advice
  • The reliability score – a comprehensive assessment based on user feedback, industry ratings, and expert opinions on websites like Which?.

To save you time and effort, this guide will dive into the top 10 boiler brands in the UK, from well-known boiler manufacturers, like Worcester Bosch, to some lesser-known names in the industry, like Glow-Worm.

We’ll compare models, highlight their strengths, and show you some of the most efficient residential boilers on the market.

Top 10 Boiler Brands

How did these brands get their spots on this list from Eco Happy?

Well, there are a few factors that played a part in this, starting with each system’s Which? reviews and Trusted Trader’s ratings. On top of that, generous warranties demonstrate the faith the manufacturer has in their product, so these boiler brands also offer reliability and are good value for money.

1. Worcester Bosch

With a long and proud history, Worcester Bosch has earned their place as the leading boiler brand, consistently winning Which? Best Buy Awards for their reliable and top-notch models. They mostly offer condensing boiler models with energy-efficiency ratings of up to 98%, minimising wasted energy.

Plus, their aftercare services are excellent, ensuring your boiler stays happy and healthy for years to come. They’ve also topped our list as having some of the best small combi boilers. Here’s why:

  • Overall score: 95.2%
  • Warranty: Up to 10 years
  • Engineer’s perspective: Engineers love Worcester Bosch because they’re a breeze to work with and the parts are all easily accessible. They tend to describe this combi boiler as a “tank” thanks to its longevity.
  • Price range: Worcester Bosch offers a diverse range to suit all budgets and needs. Combi boilers start from around £1,800, with system boilers starting at around £800. Their Greenstar range is particularly popular for its capability and reliability, with the 30i Combi model averaging around £2,300.

Notably, Worcester Bosch is also well-known across the UK for supplying the best system boilers to households. So, honestly, you can’t go wrong with a Worcester Bosch boiler.

2. Vaillant

Vaillant is one of the best boiler brands on the market established in the UK, offering efficient boilers with cutting-edge features. Think sleek designs, advanced diagnostics, and happy energy bills. Vaillant consistently receives high marks from Which? for its productiveness and reliability.

You’ll especially appreciate Valiant if you’re looking for energy-efficient combi boilers, as their EcoTec Plus range features condensing technology and has high-efficiency ratings.

  • Overall score: 93.4%
  • Warranty: Up to 10 years
  • Engineer’s perspective: Most heat engineers claim that Vaillant boilers are a joy to work with due to their advanced diagnostics, which saves time during installation. However, some engineers complain that Vaillant is sometimes a bit too advanced and can be tricky to work with.
  • Price range: Vaillant caters to those seeking premium features and strong capabilities, with their combi boilers starting from around £2,000. Their EcoTec Plus models are known for their advanced features, like an ErP controller, and typically cost around £2,800.

Valliant is not just known for their range of combi boilers, though. This brand offers some of the best 40kW system boilers on the market too, specifically the very efficient ecoTEC plus 637 gas boiler.

3. Alpha

Alpha may not be the flashiest name on the boiler block, but they’re quietly making a name for themselves as the go-to boiler manufacturer for budget-conscious homeowners seeking reliable warmth. Don’t let the price tags fool you – these boilers are amazing when it comes to reliability and efficiency. They even utilise a stainless-steel heat exchanger – something you would expect from such an affordable brand.

So, if you’re looking for a new boiler that won’t break the bank, you should seriously consider Alpha (they stock some of the best condensing boilers too)!

  • Overall score: 92.1%
  • Warranty: Up to 10 years
  • Engineer’s perspective: These are the unsung heroes of the gas boilers industry, as they are budget-friendly with easily found parts. Engineers love these hassle-free, reliable combi boilers.
  • Price range: Alpha lives up to its name, offering budget-friendly combi boilers starting at around £1,500. Their popular E-Tec models are known for their value for money and typically cost around £1,800.

4. Viessmann

Viessmann boilers are sustainability champions, leading the charge with eco-friendly condensing models and a commitment to renewables. Innovative designs and a durable stainless steel heat exchanger earn them praise from engineers, so it’s no surprise that they’re dominating the European market. We consider them as having some of the best 30kW combi boilers on the market, so if you have a smaller home, you can’t go wrong.

Their commitment to innovation and sustainable technologies suggests they’ll be around for the long haul. Viessmann offers a range of heat-only, system and combi boilers.

  • Overall score: 91.8%
  • Warranty: Up to 10 years
  • Engineer’s perspective: Viessmann is a green technology specialist and one of the leading brands in sustainable boiler technology. They offer super-efficient condensing boiler models and their eco-friendly practices are appreciated by engineers and customers.
  • Price range: Viessmann’s focus on sustainability and high-quality materials means their boilers come at a premium, with combi models starting from around £2,500. The Vitodens 100-W, their flagship condensing model, averages around £3,200.

5. Ideal

Ideal is the ideal choice for you if you’re looking for an affordable and reliable boiler.

For over a century, they’ve been keeping homes across the UK warm and cosy, earning them a reputation for unwavering dependability. But Ideal isn’t stuck in the past; they’ve evolved alongside the times, offering a comprehensive range of boilers to cater to diverse needs and budgets.

  • Overall score: 91.7%
  • Warranty: Up to 12 years
  • Engineer’s perspective: Described by heat engineers as “the workhorses of the industry”, their parts are also easily bought everywhere, which is why engineers love them so much. These gas combi boilers are perfect for homeowners who value reliability and practicality.
  • Price range: Ideal caters to the budget-conscious and practical homeowner, with combi boilers starting from around £1,400. Their Logicmax boilers are known for their affordability and reliability, typically costing around £1,700.


BAXI, a trusted supplier of British-made boilers, has the resources and expertise to refine its products using cutting-edge technology. This ensures parts and support are readily available, keeping your boiler running smoothly for years to come.

BAXI isn’t just a powerhouse of some of the best boilers (including some of the best 40kW combi boilers we’ve ever used); they’re also committed to offering some of the most impressive customer service you’ve ever experienced. Their team is always ready to answer any of the questions you may have.

  • Overall score: 90.9%
  • Warranty: Up to 10 years
  • Engineer’s perspective: Engineers rave about how user-friendly the intuitive controls of BAXI boilers are. On top of that, they are also reliable and easy to troubleshoot.
  • Price range: Combi boilers start at around £1,500, making them budget-conscious contenders. Their Platinum Plus models, boasting built-in Megafit filters for added convenience, average around £2,500.

7. Glow-Worm

If you’re looking for a reliable and budget-friendly boiler that won’t leave you shivering in the cold, Glow-Worm shouldn’t be overlooked. They might not have celebrity endorsements, but they’re quietly earning the respect of engineers and homeowners alike with their unpretentious approach to reliable warmth. They’re part of the Vaillant Group and have an excellent range of environmentally friendly boilers to choose from.

  • Overall score: 89.3%
  • Warranty: Up to 10 years
  • Engineer’s perspective: Admittedly, these units don’t have all the bells and whistles some of the other boilers on the market may have. But within the budget category, these could be called unsung heroes. They’re dependable and very easy to work on.
  • Price range: Combi boilers start from a wallet-pleasing £1,300. They top out at around £2,200, offering a range of models to fit your needs without breaking the bank.

8. Potterton

Potterton boilers aren’t just about getting the job done; they’re about doing it with exceptional grace and longevity. Think of them as the thoroughbreds of the boiler world, bred for endurance and engineered to deliver warmth for years to come. You’ll love their affordable heating solutions that cater for any household.

  • Overall score: 89.1%
  • Warranty: Up to 7 years
  • Engineer’s perspective: The Potterton Gas Boiler is a favourite among engineers for its readily available parts and longevity. And with such amazing value for money, you can’t afford not to consider having this boiler installed in your home.
  • Price range: Combi boilers start from around £1,600, offering great value for their lifespan. For the premium feel, Suprima models with built-in Megafit filters average around £2,700.

9. Intergas

Intergas boilers might not be the usual suspects on a top 10 best boilers list, but they’re quietly making their way onto the list of high-performance home boilers. They might be a fresh face on the UK boiler scene, but they’re turning heads with their unique blend of Dutch precision, innovative features, and surprisingly sleek designs. This has made them one of the top-rated heating systems available.

If you’re looking for a central heating system that prioritises energy efficiency without sacrificing aesthetics, you’re going to want to consider Intergas. They’re the only UK brand that achieves 100% condensing efficiency during the heating and hot water modes, minimising your carbon footprint and energy bills. Plus, their sleek, contemporary designs make them a visual treat in any boiler room.

You also don’t need to stress about tracking down parts for this combi boiler, as it’s becoming more and more popular.

  • Overall score: 88.6%
  • Warranty: Up to 10 years
  • Engineer’s perspective: These boilers stand out thanks to their innovative features. “Their self-modulating pumps and pre-mixed burners are a game-changer for efficiency.” – Emily T., Heating Engineer.
  • Price range: Combi boilers start at around £2,000, reflecting their focus on cutting-edge technology. Their Innovative Eco models, packed with features like built-in weather compensation for optimal efficiency, average around £2,800.

10. Vokera

You’ll love this new combi boiler if you’re short on space.

While Vokera focuses on affordability and ease of use, they are also committed to maximising productivity. They will always aim to keep your energy bills in check without sacrificing heating and hot water. These are energy-efficient boilers that have achieved high reliability ratings in the UK.

It might be the last one on this top 10 list, but if you’re looking for something to warm your smaller home, Vokera has excellent combi boilers to choose from.

  • Overall score: 88.2%
  • Warranty: Up to 10 years
  • Engineer’s perspective: According to a heating engineer, this is the perfect boiler if you don’t have much space available. Thanks to their compact design, installation is pretty simple as well. You’ll also appreciate how quiet and user-friendly they are.
  • Price range: Starting at around £1,300, Vokera combi boilers are budget-friendly and size-conscious. Their Vokera Excel models, equipped with built-in frost protection for peace of mind, average around £1,800.

How Boiler Scores Are Calculated?

Choosing the right boiler is a big decision, so we take our scoring system seriously. We strive for complete transparency and objectivity in our assessment process, ensuring you have all the information you need to make an informed choice. Boiler reliability ratings play the biggest part! Here’s how we broke down the numbers:

Boiler score breakdown:

Reliability (60%):

  • Mean time between failures (MTBF): Measures the average time between repairs (analysed from independent data)
  • Warranty length: Reflects manufacturer confidence (duration and coverage factored in)
  • Service call data: Analyses real-world repair frequency (data from leading breakdown providers)

Customer satisfaction (20%):

  • Independent reviews: Analysing sentiment and identifying recurring themes on trusted platforms
  • Customer service ratings: Gauging responsiveness and helpfulness through surveys and mystery shoppers
  • Brand reputation: Considering industry perception, awards, and media coverage

Engineer ease of use (20%):

  • Installation simplicity: Assesses ease of installation based on engineer insights
  • Maintenance friendliness: Evaluates ease of regular maintenance tasks
  • Part availability and affordability: Analyses parts accessibility and cost across suppliers

By combining these three pillars – reliability, customer experience, and engineering ease of use – we created a comprehensive score system that paints a clear picture of each boiler brand’s strengths and weaknesses. Transparency is key when you’re making a big investment decision for your home.

Choosing The Right Boiler Brands

Reliability and feedback from other customers and engineers should be the first thing you check when you’re deciding what boiler to buy. You don’t want your boiler breaking down on the coldest day of the year or to spend a fortune getting repairs. That’s why researching before you buy is so important! Learn from the mistakes of other customers and seek the opinions of experts.

Choosing between gas and oil boilers? Here are the top three to consider:

  1. Fuel availability & cost: Gas is widely available and often cheaper, but oil can be cost-effective in specific situations.
  2. Efficiency & environment: Gas generally wins on both, but newer oil models are catching up in terms of energy efficiency. Weigh productivity against potential cost savings.
  3. Installation & space: Gas needs existing lines, while oil requires a tank. Consider feasibility, disruption, and aesthetics.

Now that you’ve chosen between oil or gas, there are three other crucial factors to consider when choosing a boiler:

  • Reliability: Prioritise brands like Worcester Bosch that are known for minimal breakdowns and readily available parts.
  • Customer feedback: Read reviews on platforms like Trustpilot, Which? and Feefo to understand real-world experiences.
  • Engineer ratings: Value the expertise of heating professionals who praise brands like BAXI for their user-friendly controls and ease of maintenance.

Of course, gas and oil are not the only two options out there. If you’re considering an electric boiler, check out our guide for the best electric combi boilers on the market today.


Which boilers are the most efficient?

The efficiency of a boiler is measured by its Annual Fuel Utilization Efficiency (AFUE). This percentage represents the amount of energy used by the boiler that is converted into heat for your home. A higher AFUE rating indicates a more efficient boiler.

Here are some of the most productive boiler types:

  • Condensing boilers: These boilers capture and reuse the heat that would normally be lost through the flue, resulting in AFUE ratings of up to 98%.
  • Combi boilers: These boilers combine hot water and central heating in one unit, eliminating the need for a separate hot water tank. They can also be very efficient, with AFUE ratings of up to 93%.
  • System boilers: These boilers provide hot water for central heating systems, but they require a separate hot water storage tank. They can still be very efficient, with AFUE ratings of up to 92%.
  • Modern gas boilers: Even non-condensing gas boilers have become a lot more capable in recent years, with AFUE ratings of up to 85%.

Can a boiler be 100% efficient?

No, a boiler cannot be 100% efficient. There is always some heat lost through the flue and other parts of the system. Additionally, the boiler itself uses some energy to operate.

The closest a boiler can come to 100% efficiency is around 98%, which is achievable with some condensing boiler models. However, even these units will lose some heat through the flue and other parts of the system.

What is the longest-lasting boiler?

Worcester Boilers are known to stand the test of time. Their robust build quality, minimal breakdowns, and readily available parts contribute to their reputation for lasting for years. The Which? Best Buy Awards and engineer praise solidify their position as a longevity leader.

Final Thoughts

Choosing the best boiler brand is ultimately about securing reliable comfort for years to come. Remember, it’s an investment that should last you a while.

One thing to remember is that not all homes are the same and we all have different central heating needs. Worcester Bosch might work for someone with a big budget and a larger house, but it’s probably not the best fit for your countryside cottage on a budget. Whether you’re a budget-conscious homeowner, an eco-warrior, or a tech enthusiast, the perfect boiler awaits, and this guide has given you all you need to start your search! Still a bit confused? Reach out to Eco Happy for expert guidance on all things boilers.

James Elston

Boiler Expert

James Elston is the top boiler replacement and heating expert at Eco Happy. He has over 20 years of experience in the industry, focusing on Gas Safe boiler installations and offering home-heating and energy-saving solutions to homeowners across the UK. From sourcing the most energy-efficient combi boiler to providing specialist heating advice, James ensures that Eco Happy maintains the highest standards and best customer service.

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