Eco Happy (Solar Expert)

Published February 28, 2024

Are you looking for the best combi boiler on the market? There are numerous options to choose from, which can be overwhelming. You may need a new combi boiler because your old one conked out, or want to reduce your energy bills. Whatever the reason, this guide will help you find a reliable option.

We are Eco Happy, your go-to helpers for your energy needs. Our guide covers the 16 best combi boilers in the UK from the top boiler manufacturers. We will also dive into how to choose the best combi boilers and other common queries.

The Top 16 Combi Boilers In The UK

  1. Viessmann Vitodens 050-W
  2. Viessmann Vitodens 100-W
  3. Worcester Greenstar 8000 Combi
  4. Worcester Bosch CDi Compact
  5. Ideal Vogue Max 32
  6. Ideal Logic+
  7. Vaillant ecoFIT Pure 825C
  8. Vaillant ecoTec Plus
  9. Baxi 800 Combi Gas Boiler
  10. Baxi Duo-tec Combi
  11. Vokera Evolve C Combi Boiler
  12. Vokera Easi-Heat i 25C
  13. Potterton Gold Combi
  14. Potterton Titanium 28
  15. Glow Worm Energy7 30C
  16. Alpha E-Tec NX

Best Viessmann Combi Boilers

Viessmann is a top boiler manufacturer that uses German engineering to produce efficient and affordable central heating. Their Vitodens range is remarkable, and are easily considered among the best combi boilers on the UK market. The company has been in the industry for over 100 years and offers a wide range of heating solutions, from combi boilers to solar thermal systems.

1. Viessmann Vitodens 050-W

You’ll find many raving reviews about the Viessmann Vitodens 050-W. This gas boiler is available in 25kW, 30kW and 35kW. It also has a compact size so it can be easily hidden in a cupboard, making it well-suited for small and medium-sized homes. Plus, you can expect an easy installation.

  • Why it’s good: The Vitodens 050-W offers great value for money. It’s technologically advanced and is a highly energy-efficient combi boiler.
  • Cost: Prices start from £1,845 for the boiler.
  • Features:
    • It is a hydrogen-ready boiler that can come into use when the UK Government implements its net zero plan to switch from fossil fuel gas to hydrogen gas.
    • It has built-in wifi compatibility, so it can be easily connected with smart thermostats. With a smart thermostat, you can switch your boiler on and off remotely.
    • It is a compact boiler, measuring 400 mm (w) x 350 mm (d) x 707 mm (h) and weighs 36 kg.
    • Domestic Hot Water (DHW) flow rate of 12–13.4 litres a minute.
    • It comes with a standard three-year guarantee which can be increased to 10 years if it’s installed by a Viessmann-trained installer.
  • Pros:
    • The Viessmanns Vitodens 050-W is known to be a quiet boiler.
    • With a smart thermostat, Viessmann customer service can remotely diagnose problems with the boiler.
    • An easily operated touchscreen display.
    • This high-quality combi boiler offers value for money thanks to its high efficiency and advanced technology.
  • Cons:
    • This model can only handle a maximum of two bathrooms and doesn’t suit homes with an excessive hot water demand.
    • You must buy the smart thermostat separately to gain the full benefits of the wifi compatibility.
    • All the components are only compatible with those manufactured by Viessmann. This means repairs may take longer due to the need to find parts.

2. Viessmann Vitodens 100 W

The Viessmann Vitodens 100-W is a reliable combi boiler that suits larger homes. Domestic hot water and central heating are no problem for this beast of a combi boiler.

There are three outputs available, including 26 kW, 30 kW, and 35 kW. The 30 kW combi boiler can support a four-bedroom house with two bathrooms and up to 15 radiators. Alternatively, the 35 kW can handle more rooms, bathrooms, and 20 radiators.

  • Why it’s good: It is one of the most powerful combi boilers for larger homes, while offering the same benefits as a Vitodens 050-W.
  • Cost: The price for each output is around £1,777 (30 kW) and £1,873 (35 kW) on Viessmann’s website.
  • Features:
    • Hydrogen-blend ready.
    • One of the most energy-efficient condensing gas boilers with a rating of 94%.
    • Stainless steel heat exchanger which lasts longer than those made of aluminium.
    • It is compact at 400 mm (w) x 360 mm (d) x 700 mm (h) and weighs around 35 kg. This makes it kitchen-cupboard friendly!
    • The 100-W has built-in wifi and and user-friendly touchscreen display.
  • Pros:
    • It is a powerful combi boiler that larger homes can enjoy.
    • The same technological benefits as the 050-W.
    • Comes with a 3 to 10-year guarantee, depending on if you use a Viessmann-accredited installer.
    • One of the quieter gas combi boilers.
  • Cons:
    • Incompatible with non-Viessmann parts.
    • The only compatible smart technology is from the Viessmann brand.

Best Worcester Bosch Combi Boilers

Worcester boiler reviews reveal that the brand is known for exceptional quality. If you’d like your combi to last for years to come, Worcester Bosch boilers have a reputation for lasting up to 15 years – possibly even more. Their guarantee of up to 12 years is also something customers appreciate. The brand is also known for great customer service.

1. Worcester Bosch Greenstar 8000

The Worcester Bosch Greenstar 8000 is available in both combi boiler and system boiler versions. The Greenstar 8000 combi boiler is worth raving about. It is sleek-looking, well-built, powerful, and super energy efficient.

  • Why it’s good: This top-rated combi boiler can supply central heating and hot water to almost any size home thanks to the various output options.
  • Cost: The Worcester Gosch Greenstar 8000 combi has a price tag upwards of £1,643 (excluding installation), depending on the output. The 45 kW version costs around £2,346.
  • Features:
    • A-rated with a commendable 94% efficiency rating.
    • Hydrogen-blend-ready.
    • The boiler size is 440 mm (w) x 365 mm (d) x 780 mm (h) and weighs 62 kg.
    • You can get Greenstar 8000 combi boilers in multiple outputs from 30 kW to 50 kW.
    • Intelligent Filling System technology maintains optimum water pressure and alerts you if something goes wrong with the boiler.
    • A full-colour touchscreen display with advanced features.
  • Pros:
    • Adaptable power and flow rate options that can handle high heat and hot water demands.
    • The modern design means that the boiler doesn’t necessarily need to hide away in your kitchen cupboard. However, it is small enough to fit there!
    • You can buy this model whether you’re in an apartment or a large multi-bedroom home.
    • The Greenstar 8000 can connect to a smart thermostat for convenient control and monitoring.
  • Cons:
    • Worcester boiler prices can be quite steep because they are a premium manufacturer.
    • You need to hire a Worcester Bosch-accredited installer to validate your guarantee.

2. Worcester Bosch CDi Compact

The CDi Compact offers high build quality, user-friendliness and energy efficiency. The high efficiency allows you to save on energy bills while still enjoying uninterrupted heat. The CDi Compact is also ideal for apartments because it’s small. In fact, it is one of the most compact combi boilers on the market!

  • Why it’s good: This model has built-in frost protection, which can handle cold UK temperatures extremely well.
  • Cost: Prices range between £1,105 and £1,359 for the unit.
  • Features:
    • An ErP rating of A, with 94% energy efficiency.
    • The CDi Compact stays true to its name, measuring 390 mm (w) x 280 mm (d) x 680 mm (h) and weighing only 32.9 kg.
    • Comes in three options: 28 kW, 32 kW, and 36 kW.
    • Hydrogen-blend ready.
    • The boiler can sync with smart thermostats.
  • Pros:
    • The CDi Compact is easy to use with simple controls.
    • The hot water can be adjusted according to your needs.
    • It has a low-energy pump that reduces electricity usage.
  • Cons:
    • It can only heat smaller homes with a maximum of two bathrooms.
    • It has an aluminium heat exchanger, which wears out over time. This can reduce the efficiency and may need frequent maintenance.

Best Ideal Combi Boilers

Ideal boiler prices are cheaper than average while packing a punch in quality. Ideal is a competitive brand with tempting gas boiler options. The company aims to bring harmony between energy efficiency, technology, and quality – and they do it well.

1. Ideal Vogue Max 32

This is easily one the best combi boilers money can buy. Why? Their low prices are paired with a multitude of benefits that competitors have yet to match in terms of affordability. From money-saving efficiency ratings to high-quality materials, the Ideal Vogue Max 32 is a force to be reckoned with. This model suits medium homes with 3+ bedrooms and up to 14 radiators.

  • Why it’s good: This model is Ideal’s latest and greatest, with one of the best efficiency ratings in its price range at 93.2%.
  • Cost: The prices of Ideal Vogue Max 32 combi boilers range between £1,109 and £1,340.
  • Features:
    • Stylish design with a user-friendly LCD interface.
    • Full modulation and built-in frost protection.
    • Available in outputs of 15 kW, 18 kW, and 26 kW.
    • The dimensions are 330 mm (d) x 450 mm (w) x 740 mm (h), weighing 38.9 kg.
    • Hydrogen-blend-ready.
  • Pros:
    • The boiler has a built-in system that will give you fault codes when something goes wrong. This makes it easy to troubleshoot.
    • The Vogue Max 32 has many features and benefits that outcompete other combi boilers in its price range.
    • You can get a boiler warranty for up to 12 years with an Ideal-qualified installer.
  • Cons:
    • The Vogue Max 32 is too large to hide in a standard-sized cupboard, and can’t hang on a wall, so it will need to take up space. Luckily it has a sleek design.

2. Ideal Logic+

Looking for the best combi boiler for a medium-sized home? Consider the Ideal Logic+ with a 35 kW output option, which can handle around two bathrooms and 20 radiators. This model is also one of the most affordable energy-efficient combi boilers on the UK market.

  • Why it’s good: It is one of the more cost-effective boilers for mid-size homes. It offers brilliant quality, durability, and energy efficiency.
  • Cost: Prices start at around £1,083, excluding installation.
  • Features:
    • A-rated, 94% energy efficiency.
    • User-friendly, backlit LCD screen.
    • The size measures 395 mm (w) x 278 mm (d) x 700 mm (h) and weighs 34 kg.
    • Frost protection features that can brave the cold UK weather without freezing up.
    • The available outputs include 24 kW, 30 kW and 35 kW
  • Pros:
    • The compact design is helpful to those who are looking to keep their boiler out of sight.
    • The Logic+ is Quiet Mark awarded, meaning it is a silent boiler.
    • It is compatible with smart thermostats.
    • The standard warranty is 7 years but extends to 10 years when installed by a brand-accredited installer.
  • Cons:
    • It has an aluminium heat exchanger, which is often seen as of lesser quality than those made of steel.

Best Vaillant Combi Boilers

Vaillant is a well-reviewed German boiler manufacturer and is seen as one of the best companies for combi boilers. They have a high rating among clients, and their products are durable, with boilers lasting up to 15 years. One notable feature of the brand is that its products are hand-built to ensure only the best quality.

1. Vaillant EcoTec Plus

This condensing combination boiler is one of the most popular choices. It is an affordable, effective combi that suits medium-sized homes with up to two bathrooms and 15 radiators. The EcoTec Plus is also a quieter combi boiler compared to other brands like Worcester Bosch and Baxi.

  • Why it’s good: It is the top mid-range combi boiler on the market.
  • Cost: Vaillant boiler prices are generally affordable; the EcoTec Plus starts at around £1,350.
  • Features:
    • An ErP A rating, with an operation of 89.3% efficiency.
    • The boiler size is 440 mm (w) x 338 mm (d) x 720 mm (h) and 36 kg – which is still small enough to fit into a cupboard.
    • You can opt for a 35 kW or 38 kW output.
    • You can pair the EcoTec Plus with a smart thermostat to control the boiler according to your heating needs.
  • Pros:
    • It has a stainless steel heat exchanger and high-quality components, bound to last well past its 5-year warranty.
    • This boiler is compatible with aroTHERM air-to-water heat pumps. This means you can enjoy a hybrid system that saves on energy costs.
    • This model is a breeze to install and repair.
  • Cons:
    • Although the EcoTec Plus is high-quality and built to last, the 5-year standard warranty is much shorter than what other brands offer.

2. Vaillant ecoFIT Pure 825C

The Vaillant ecoFIT Pure 825C is one of the best combi boilers thanks to its value for money. It is not as high-tech as those in the Worcester Bosch Greenstar range, but it does give you everything you need at a reasonable price. These gas combi boilers are perfect for flats and smaller homes.

  • Why it’s good: It is one of the quietest combi boilers out there due to its reduced noise design.
  • Cost: The price starts at £1,254 for the boiler.
  • Features:
    • You can choose an output range of 25 kW, 30 kW or 35 kW.
    • A-grade, 89.3% efficiency rating.
    • Hydrogen-blend-ready.
    • It has compact dimensions, measuring 390 mm (w) x 295 mm (d) x 700 mm (h) and weighs around 33 kg.
  • Pros:
    • This combi boiler is super easy to install and maintain.
    • You can integrate it with a smart thermostat to enjoy scheduled heating.
    • A modern design that is easy on the eye, which is helpful if you don’t have cupboard space.
  • Cons:
    • The ecoFit Pure 825C can support a maximum of two bedrooms with one bathroom and 10 radiators.
    • This model only has a maximum warranty of 7 years if installed by a Vaillant-qualified engineer.

Best Baxi Combi Boilers

If you’re looking for a new combi boiler, you’ve likely considered Baxi – one of the most popular boiler manufacturers known for their affordability and reliability. They have been around for over 150 years and know the industry well. They also cater to various price ranges while maintaining quality.

1. Baxi 800 Combi Gas Boiler

If a top-of-the-range gas combi boiler doesn’t fit your budget,Baxi boiler prices will save the day. This is especially true for the 800 Combi. This option is energy-saving, powerful, and affordable. It offers everything you need and can support a four-bedroom, two-bathroom home with 10 radiators.

  • Why it’s good: The 800 Combi is a cost-friendly option from a highly reputable brand that offers a 10-year warranty.
  • Cost: A Baxi 800 Combi boiler costs between £1,103 and £1,585.
  • Features:
    • An A-rated combi boiler with a 93% energy efficiency rating.
    • This boiler is available in central heating outputs of 25 kW, 30 kW, and 36 kW.
    • The 800 Combi has a compact, cupboard-friendly size. The measurements are 390 mm (w) x 285 mm (d) x 700 mm (h).
    • Hydrogen-blend-ready.
    • The Baxi 800 can connect to a smart thermostat, allowing you to control your heating remotely.
  • Pros:
    • A highly efficient boiler that saves you money and helps the planet by reducing the need to burn more fossil fuels.
    • It has a magnetic system filter to protect the central heating system against debris build-up.
    • Comes with an impressive 10-year extended warranty.
  • Cons:
    • The Baxi 800 Combi is not the best option for homes with high water demands. It can also only handle a maximum of 10 radiators – which is less compared to other options on this list.

2. Baxi Duo-tec Combi

The Baxi Duo-tec is a popular combi boiler installed in many UK homes. This tried-and-tested model is easy to install and maintain. It is also so simple to use that even your six-year-old could understand how to work it. The Baxi Duo-tec has a range of outputs to suit almost all heating and hot water needs.

  • Why it’s good: This model is popular because of its exceptional quality and durability.
  • Cost: A new boiler in this Baxi range typically costs between £925 and £1,500.
  • Features:
    • The Duo-tec gas combi boiler has an impressive 92% rating.
    • The boiler measurements are 450 mm (w) x 345 mm (d) x 780 mm (h), which is small enough for cupboard spaces.
    • You can get a Duo-tec combi boiler in 24 kW, 28 kW, 33 kW, and 40 kW outputs.
  • Pros:
    • Easy to install and repair. Baxi is a brand that almost all Gas Safe engineers understand, and the Duo-tec combi boiler is likely no stranger to them either.
    • It is endorsed by the Energy Saving Trust – an independent organisation devoted to energy conservation. They wouldn’t endorse something unless they genuinely believed in it!
    • The energy efficiency of this model means you get to enjoy reduced energy costs.
    • Comes with a 7-year parts and labour warranty.
  • Cons:
    • The 40 kW Duo-tec can only handle two bathrooms and 15-20 radiators, which is a low amount considering the high output.

Best Vokera Combi Boilers

Vokera is a budget option if you don’t want to spend much on a new boiler. They have many combi boilers on offer, but the Evolve C Combi Gas Boiler and Easi-Heat i 25C are the best options.

1. Vokera Evolve C Combi Gas Boiler

Are you in need of a reliable combi boiler? The Vokera Evolve C is all that and more. From its 10-year warranty to its energy effectiveness, this option has it all. In addition, the Evolve C’s many features and benefits make it an advanced and capable model.

  • Why it’s good: The Evolve C Combi is Vokera’s top energy-efficient model that suits various home sizes, from small to large.
  • Cost: This model costs between £841 and £1,026, depending on the output.
  • Features:
    • The Evolve C has an impressive 92% and an ErP A rating.
    • This model is available in 24 kW, 28 kW, 32 kW, 36 kW, and 42 kW.
    • The dimensions are 420 mm (w) x 275 mm (d) x 740 mm (h).
    • A fully backlit LCD screen for easy reading.
    • Capable of handling a hydrogen-fossil fuel blend.
  • Pros:
    • It can handle the UK freezing temperatures thanks to the built-in frost protection.
    • The controls are straightforward, and the boiler offers an easy installation.
    • Comes with a reliable 10-year warranty.
  • Cons:
    • It doesn’t have a high build quality and has an aluminium heat exchanger, which is less efficient than steel.

2. Vokera Easi-Heat i 25C

The Easi-Heat i 25C is a lightweight, compact combi boiler that allows for easy and flexible installation. This combination boiler only suits smaller homes with low heating needs, ideally with one bathroom and a maximum of 10 radiators.

  • Why it’s good: A Vokera boiler, like the Easi-Heat i 25C, is usually priced around £300–£550, which is cheaper than competitors like Worcester Bosch.
  • Cost: This model costs around £521 for the boiler only.
  • Features:
    • An 89.1% seasonal efficiency rating.
    • Comes in 25 kW, 29 kW and 32 kW outputs.
    • This conveniently sized combi boiler is only 400 mm (w) x 275 mm (d) x 700 mm (h) and weighs 28.5 kg.
    • Has a built-in digital clock that displays error codes for easy troubleshooting.
    • An anti-cycling feature that prevents energy wastage.
  • Pros:
    • The Easi-Heat i 25C is a budget-friendly option for those who don’t want to pay a premium price but still want an energy-efficient boiler.
    • It comes with built-in frost protection to survive harsh temperatures.
    • All Vokera models are compatible with OpenTherm – a Vokera-brand smart thermostat that can help increase the boiler’s efficiency.
  • Cons:
    • It isn’t the most reliable combi boiler because the standard warranty only covers you for 5 years. However, the boiler can last up to 15 years.

Best Potterson Combi Boilers

Potterson is a reputable British brand that has been in the industry for over 150 years. Whatever your hot water and heating needs, Potterson has a reliable, budget option. They are known to cater for almost all sized homes and their boilers can last up to 15 years without repair issues.

1. Potterton Gold Combi

The Potterson Gold Combi is available in both gas and LPG models. This boiler is affordable and can suit small to medium homes. Overall, the Gold is a dependable boiler at an affordable price, made with high-quality parts.

  • Why it’s good: The Gold is Potterson’s flagship model, which competes as one of the best combi boilers on the UK market.
  • Cost: Starts at around £780 for the boiler only.
  • Features:
    • ErP A-rated and 89% efficient.
    • You can choose between outputs of 24 kW, 28 kW, and 33 kW.
    • The measurements are 450 mm (w) x 345 mm (d) x 780 mm (h).
    • A smart control system that automatically adjusts the heat output to help lower fuel consumption.
    • Flexible flue options of up to 20 meters.
  • Pros:
    • The Gold is made with high-quality components and goes through extensive quality testing.
    • It is easy to install and is low maintenance.
    • The compact size allows the boiler to fit into kitchen cupboards.
    • Good value for money thanks to its quality and affordability.
  • Cons:
    • Even though the Gold is a quality boiler, it only has a 2-year parts and labour warranty.

2. Potterton Titanium 28 Combi

This Potterson combi boiler is highly efficient and fully capable of meeting your heating and hot water needs. The Energy Saving Trust has also given it its stamp of approval. The Titanium 28 comes in various outputs to suit a wide range of heating demands.

  • Why it’s good: Titanium boilers are highly reliable and meet almost all heating needs.
  • Cost: Ranges between £1,635 and £2,135.
  • Features:
    • A brilliant 91.1% energy rating.
    • You can get outputs of 24 kW, 28 kW, 33 kW and 40 kW.
    • The Potterson Titanium 28 measures 450 mm (w) x 345 mm (d) x 780 mm (h) and is wall-mounted.
  • Pros:
    • A warranty of up to 7 years.
    • The Titanium 28 is endorsed by the Energy Saving Trust.
    • Comes with extensive flue options that can support up to 20 metres.
    • It is a straightforward boiler that allows for easy installation.
  • Cons:
    • This is slightly more expensive than other boiler brands, like Baxi, with similar features.

Best Other Combi Boilers In The UK

Glow-worm and Alpha have some competing combi boilers that deserve a spot on this list. Glow-worm boilers are of high quality with high customer satisfaction ratings to back them.

Alpha boilers are easy on the wallet and the company backs their boilers with up to a 10-year warranty, which says a lot about their reliability. They’re also known to offer brilliant customer service.

1. Glow-worm Energy7 30C

This excellent medium-budget boiler has a lot to offer. The Energy7 30C has an attractive design that’s simple to understand, and it’s available in various energy outputs. It is also small enough to hide away in a cupboard and suits a three-bedroom house with one bathroom and low hot water needs.

  • Why it’s good: The Energy7 30C is a dependable and quiet combi boiler.
  • Cost: This model costs upwards of £950.
  • Features:
    • The efficiency rating is a decent 89.2%
    • It is a compact cupboard-friendly size that measures 390 mm (w) x 280 mm (d) x 700 mm (h).
    • You can get the Energy7 30C in 25 kW, 30 kW, and 30 kW.
    • Top and rear flue options for easy installation.
  • Pros:
    • It has a modulating Grundfos pump that adapts to your heating needs to save on efficiency.
    • A Quiet Mark rating.
    • You can get up to a 10-year warranty, which is fair for the price.
    • It has a decent flow rate of 14.2 litres per minute.
  • Cons:
    • You need to use a Glow-worm Club Energy Installer to receive a 10-year warranty, otherwise it shortens to 7 years.

2. Alpha E-Tec NX

The E-Tec NX is a budget option for small-to-medium apartments and homes. Even though the cost might say otherwise, it is made with quality components. Alpha boilers have a good reputation, and this combi boiler is one of their best options.

  • Why it’s good: The quality components and low price offer great value for money.
  • Cost: The E-Tec NX boiler price starts from around £675.
  • Features:
    • An impressive seasonal efficiency of 93%
    • The model is available in outputs of 28 kW and 38 kW.
    • The dimensions are 440 mm (w) x 255 mm (d) x 712 mm (h).
    • Zinc-plated expansion vessel that helps prevent corrosion.
    • A high flow rate of 14.1 litres per minute.
  • Pros:
    • This model has a stainless steel heat exchanger, indicating that the boiler has high-quality components.
    • Easy to install and keep out of sight thanks to its compact dimensions.
    • It has a Grundfos pump, which efficiently adapts to your heating needs.
    • An easy-access front panel that makes servicing and repairs quick and easy.
    • The boiler comes with a decent 10-year warranty.
  • Cons:
    • It only has two outputs available, meaning this option is only viable for small-to-medium homes.

How We Chose The Best Combi Boilers

Value for money

The boilers mentioned balance quality and price. Combi boilers usually average between £500 and £3,000 and installation adds another £500 – £1,000, leaving the entire bill possibly at £4,000. Since a new boiler is a rather large expense, we considered value for money as a key aspect.

Customer and professional reviews

We scanned multiple evaluations for each boiler to find only the best money can buy. However, it’s easy to review something from one perspective. That’s why we took what customers had to say into account too.

Brand reputation

Some of these brands have been in the boiler industry for over 100 years, like Viessmann and Baxi. Others have also passed the 50-year mark. We picked the brands on this list because they’re experienced, reputable, and reliable.

How To Pick The Best Combi Boiler

Choosing the best combi boilers for your home ensures you receive efficient heating and hot water supply. There are various factors to consider, from house size to energy efficiency. Let’s take a look at the key considerations when choosing the best combination boiler.

House size and heating output

The size of your home determines your heating output needs. For example, 24-27 kW combi boilers are generally best for smaller properties or apartments with one bathroom. Larger 3-4 bedroom homes with two bathrooms have a higher hot water demand and will require a 28-34 kW combi boiler. Even larger homes will likely require one that is 35-42 kW.

However, you should consider getting a conventional boiler instead of a combi boiler if you have a bigger house. A combi boiler taps directly into the main water supply which means that it cannot efficiently divide its heat output to large homes that use a large amount of hot water.


Cost is one of the most vital factors when buying a combi boiler. While you may be tempted to buy a low-cost option, you should consider the long-term cost, too. Energy efficiency and warranties are factors that save costs in the long run. A high-quality, energy-efficient combi boiler may be pricier upfront; however, you’ll enjoy lower energy and maintenance bills.

On the other hand, it doesn’t always help to break the bank. While some brands have a premium price, there are substitutes that are just as efficient. You also won’t want to buy a high-output boiler when your property doesn’t need it.

Energy efficiency

Combi boilers are often a top choice for their energy efficiency. Energy efficiency allows you to in reduce your CO2 emissions and heating costs. Your boiler will come with an Energy-related Product (ErP) and Seasonal Efficiency of Domestic Boilers in the UK (SEDBUK) rating, which can help you decide which boiler is best.

Almost all modern combi boilers have an ErP rating of A. This means there isn’t much to compare when seeking energy efficiency. When deciding on the best combi boiler, rather use the SEDBUK rating system. It is more helpful because it assigns a percentage (typically between 70% and 92%) that shows how much energy is used and wasted. If the rating says 92%, it loses 8% of its heat during operation.

Some brands use cutting-edge technology to increase heat output while decreasing energy consumption. This is another thing to look for that saves money and helps the environment.

Installation and maintenance

Need some advice on combi boiler installation? It’s best to choose an option compatible with your existing heating system. Speaking to qualified heating engineers will make this task easier, like Eco Happy.

Additionally, buy a boiler from a reputable manufacturer that is reliable and offers good customer support. Regular maintenance is essential to keep your boiler running smoothly for years to come. Therefore, you should also consider warranty coverage and the availability of spare parts when things go wrong.

Customer support and after-sales service

Investing in a combi boiler brand known for exceptional customer service will give you peace of mind and save you from headaches down the line. Read testimonials and reviews so you know what to expect. You can look at aspects like technical assistance, warranty coverage, and responsive customer service.


Which is the best combi boiler to buy?

Determining the “best” combi boiler depends on your specific heating needs, budget, and preferences. However, there is a general consensus on which boiler manufacturers offer the best combi boilers. These manufacturers include Worcester Bosch, Vitodens, Vaillant, and Viessmann.

What boilers do plumbers recommend?

Plumbers often suggest Worcester Bosch, Viessmann, and Baxi as being the top-quality boilers in the UK. These well-established brands are long-lasting and trustworthy. However, opinions and recommendations may differ depending on your needs.

Which boiler brand is the most reliable?

Viessmann easily ranks as one of the most reliable boiler brands on the market. The Viessmann Vitodens 050-W and 100-W are the boilers contributing to the brand’s dependability. What’s more, Viessmann offers a 7-year parts and labour warranty if anything goes wrong. You can expect their boiler to last between 15 and 20 years.

Does the Boiler Upgrade Scheme offer help with combi boilers?

The Boiler Upgrade Scheme grant only applies to heating systems that replace fossil fuel heating systems. The options include air and ground source heat pumps or biomass boilers. If you install a biomass combi boiler, you’ll be eligible for up to £5,000.


Many reputable brands in the UK market provide excellent combi boilers. The top picks and customer favourites include Viessmann, Worcester Bosch, Ideal, and Vokera. They’re the best thanks to their high efficiency and quality. The best budget pick would be Baxi.

Eco Happy aims to give you reliable service and insightful information. Feel free to contact us to help you find the best combi boiler for your needs. We’re also happy to give you a quote to compare your options!

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