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25th November, 2024

Best Combi Boilers in 2024 (UK Buying Guide)

Best Combi Boilers in 2024 (UK Buying Guide)

Key takeaways

  • Discover the best combi boilers available on the market in 2024
  • Cost and brand reputation are significant factors in the boiler purchasing process.
  • Compare the efficiency of each boiler and estimate how much money you can save.
  • Try a new boiler quote, finance available including 0% APR.

Finding the best combi boiler for your circumstances can prove difficult. Lets discuss the best 5 boilers on the market in 2024.

Navigating the vast landscape of combi boilers can be daunting, but as 2024 unfolds, we're set to make sense of the options available to homeowners. With a variety of models vying for the title of 'best combi boiler', it's important to consider factors such as suitability for different property types, cost implications, and brand reliability.

The investment in a new boiler is not only a significant financial decision but also a move towards energy efficiency and comfort in your home.

Choosing the right combi boiler involves weighing up the functionality and features that align with your domestic needs.

Whether it's the compact nature of the Alpha boilers or the advanced technology of the Viessmann, every homeowner deserves a system that delivers consistent heating and hot water.

The market in 2024 provides a host of options, each with their unique selling points, and navigating through this spectrum is key to finding a boiler that fits seamlessly into your lifestyle.

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Best Combi Boiler Essential Insights

We've conducted thorough comparisons of various combi boilers — ideal for those ready to upgrade their home heating systems in 2024. Here's what we've uncovered:

  • Top Boiler Brands: Brands like Worcester Bosch, Viessmann, and Alpha stand out for their balance of quality and value.

  • Price Range: Expect a range of pricing options to suit diverse budgets, with premium models offering additional features.

  • Efficiency: High-efficiency ratings are standard across leading models, translating into potential savings on energy bills.

  • Warranty: Longer warranties often accompany higher-priced units, offering peace of mind regarding future repairs.

  • Features and Performance: Look for boilers with user-friendly controls, robust build quality, and strong performance metrics.

  • Installation and Maintenance: Ease of installation and the clarity of maintenance guidelines can vary, so consider these factors critically.

By understanding these elements, you're equipped to choose a combi boiler that not only meets your needs but also provides reliable and cost-effective heating for your residence.

What is a Combi Boiler?

A combi boiler, short for "combination boiler," is a type of boiler that serves as both a high-efficiency water heater and a central heating boiler integrated into one compact unit. This means it heats water directly from the mains when you turn on a tap, eliminating the need for a separate hot water storage cylinder or a cold water tank in the attic.

Combi boilers are known for their convenience and efficiency, making them an excellent choice for small to medium-sized homes where space is at a premium.

How Do Combi Boilers Work?

Combi boilers function by taking water directly from the mains supply and heating it on demand when a hot water tap is turned on or when the central heating needs to be activated. Inside the boiler, a gas burner is ignited, heating the water instantly through a heat exchanger.

Because there is no need for a hot water storage tank, the system is much simpler and quicker, providing hot water at mains pressure. As soon as you turn off the tap, the boiler shuts down, which can be a significant energy saver, reducing heating costs and minimising waste.

Why Are Combi Boilers Popular?

Combi boilers have become increasingly popular for several reasons:

  1. Space-Saving: Their compact size means they don’t require a separate hot water tank or cold water tank, freeing up valuable space in homes, particularly those with limited storage options.

  2. Cost-Effective: Combi boilers can be less expensive to install than conventional systems because the system is simpler and requires fewer components. There is no need for a tank in the loft or a hot water cylinder, reducing installation labor and material costs.

  3. Energy Efficiency: Combi boilers are highly efficient as they only heat water on demand, which minimises heat loss from stored hot water. This efficiency can significantly reduce home energy bills. The best combi boilers on the market often feature advanced condensing technology, which recovers more heat from exhaust gases than traditional boilers.

  4. Convenience and Control: Offering hot water on demand at mains pressure ensures you can enjoy powerful showers and quick filling of baths without the need for an additional pump. Modern combi boilers often come with sophisticated thermostatic controls, allowing homeowners to adjust their heating and hot water settings with precision, enhancing comfort and further improving energy efficiency.

Considering a Combi Boiler?

As the time we spend in our homes increases, the appeal of a cosy environment with steaming beverages and reliable heating grows significantly. Consequently, we might find ourselves contemplating an enhancement to our central heating system. A combi boiler, recognised for its efficiency and space-saving benefits, might just be the solution we're pondering.

  • Quick Decisions: Secure a price estimate in merely 60 seconds, with the possibility of next-day fitting.

  • Financial Flexibility: Options for 0% APR financing can make this investment more manageable.

We have curated a selection of the most commendable combi boilers of 2024, built to cater to diverse domestic needs. It's worth noting that the difference between a perfect match and a near miss in the boiler world can come down to minute details.

When looking to upgrade, consider these pointers:

  • System Suitability: Assess boilers with features that align with your home's demands.

  • Installation Options: We cater to a vast range of boilers, including top performers from this year's selection.

Whether your focus is on reducing energy bills or ensuring a warm and inviting living space, we're here to guide you towards making an informed boiler choice.

Best Combi Boilers

Understanding Combi Boilers

We consider a combi boiler a high-efficiency multipurpose solution for both central heating and hot water in a single compact unit. With these systems, you do away with the need for separate water tanks, allowing for a significant space-saving in your property. Combi boilers are straightforward to install and are recognised for their reliability, making them a popular choice in homes across the UK.

Leading Combi Boilers on the Market:

  • Worcester Bosch 4000 - renowned for its effectiveness.

  • Viessmann Vitodens 050-W - appreciated for its advanced technology.

  • Worcester Bosch 8000 - a premium choice with superior performance.

  • Ideal Logic Plus - stands out for its value and efficiency.

  • Viessmann Vitodens 100-W - balances functionality with innovation.

Whether opting for a gas combi boiler, an electric combi boiler, or even an oil boiler, we advocate assessing your household’s requirements to find the best match.

Best Combi Boilers: Ideal for Various Homes

Combi boilers cater to hot water demand and central heating simultaneously, directly linking to the water mains for immediate hot water. We find them particularly adept in smaller homes due to their compact nature—no need for separate tanks or cylinders. The gas combi boiler has become a staple in UK households, providing a heating system with water pressure-dependent power output.

  • Instantaneous hot water on demand

  • Suitable for properties with natural gas

  • Fuel type flexibility, including gas or electric models

  • Optimal for both space-saving and energy efficiency

Though robust, even these systems have a lifespan. Post a decade of service, it's prudent for us to consider an upgrade.

Reasons to Invest in a New Heating System

Enhanced Operational Effectiveness

Modern boilers embody energy-saving prowess. If you're contending with a combi boiler that's surpassed the fifteen-year mark, it's likely operating at a suboptimal level. Contrast that with the latest A-rated condensing boilers which can surpass old models by a staggering 30% in terms of energy expenditure. Not only does this reflect positively on your heating bills, but it's a stride towards lessening your home's environmental impact.

  • Up to 30% more energy efficiency compared to 10-year-old boilers

  • Condensing boilers are designed for maximum heat recovery

  • Potential savings on energy bills

  • Contributes to reduced carbon emissions

Augmented System Dependability

We seek uninterrupted comfort in our homes, and a trustworthy boiler is central to this. The advance in years comes with a dip in boiler reliability. Frequent repairs can be both bothersome and expensive. By choosing a new boiler, you substantially reduce the risk of malfunctions.

  • Lower likelihood of unexpected breakdowns

  • Boiler warranties offer peace of mind with coverage for the warranty period

  • Use of premium components like stainless steel heat exchangers enhances durability

Quieter Operating Conditions

The advent of contemporary boiler technology has ushered in a new era of serenity. Unlike their predecessors, modern boilers hum along in the background, allowing for a tranquil home environment. If your current unit is a cacophony of unsettling sounds, an upgrade promises a whisper-quiet operation.

  • Reduction in operational noise levels

  • Frost protection features to ensure silent running during colder months

  • Features designed for quiet operation

To reiterate, the benefits are multifold. An investment now not only relieves your pocket in the long run through abated energy expenses but also secures the cosiness of your living space with dependable and serene heating solutions.

Selecting Your Ideal Combi Boiler

We understand the challenge in choosing an efficient combi boiler that meets your needs, given the vast array available, each with their own merits. Prices vary too, a factor certainly not to be ignored.

  • Our Top Picks: We've considered performance and customer feedback to guide you.

    • Affordable: For budgets tight, yet quality required.

    • Efficiency Leader: Maximum heat, minimal waste.

Trust us to steer you through this landscape to a wise decision for warmth and hot water this year.

Selecting the Top Combi Boiler

Assessing Boiler Energy Efficiency

When examining combi boilers, we pay keen attention to the energy efficiency ratings. Boilers with an 'A' rating represent the pinnacle of energy conservation, which can significantly reduce heating bills in the long run.

Understanding Boiler Output

The output, measured in kilowatts (kW), is critical as it correlates with the boiler's capacity to heat your home. For most small to medium homes, a combi boiler with an output between 25kW and 30kW is often adequate, but your gas engineer will guide you to the perfect fit.

Sizing Up Your Combi Boiler

It's not just the heating capacity that matters, but also the compactness of the combi boiler. Confirming the physical dimensions is vital to ensure a smooth installation and adequate space management within your household.

Boiler Feature

Why It Matters

Energy Efficiency

'A' rating ensures top savings on bills

Output Rating (kW)

Matches boiler power to home's heating need

Boiler Physical Size

Must fit the designated installation space

We recommend always consulting a certified gas engineer who can assess your home’s flow rate and size requirements accurately. They can help you find a boiler that meets both the hot water and heating needs without unnecessary overspending on a too-powerful unit.

Cost Analysis for Combi Boiler Implementation

Variation in Pricing by Providers

We must acknowledge that the expense of acquiring a combi boiler isn't consistent across the board; it fluctuates markedly. It's not merely the model or make that swings the price tag but also where you reside and its due availability. Installing a boiler up North may prove lighter on the wallet compared to the steeper prices of the capital.

Reflect on the sort of dwelling you have—be it a terraced house or a semi-detached. The space you occupy influences not just the combi boiler suitable for you but also the installation costs. A professional will need to evaluate your living space, tallying bedrooms and water facilities, to conclude the requisite boiler size and installation complexity.

To distil it further, when budgeting for a new combi boiler, we're not simply allocating funds for the hardware.

Our homes are unique, and the variety of boilers and their installation ought to be tailored. It's pivotal for us to seek thorough quotes, merging both the device's price and the labour, to forestall surprises on the invoice.

Leading Combi Boiler Manufacturers

In the dynamic landscape of heating solutions, numerous brands stand out. We've observed consistent performance and customer satisfaction with these select names:

  • Viessmann, a top-notch industry leader.

  • Worcester Bosch, renowned for reliability.

  • Vaillant excels with innovative technology.

  • Ideal, trusted for home comfort.

  • Alpha Heating balances quality with affordability.

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Best Combi Boiler by Alpha Innovation Company

#5 Alpha Combi Boilers

In fifth place comes Alpha. This well-established brand has been one of the UK’s leading heating companies for over 50 years, giving them plenty of experience that combines traditional business values with a highly innovative approach to its operation.

Alpha ranks among the best combi boiler because they have amazing A-Class efficiency-rated budget combi boilers that accommodate the needs of every property type and household size.

As part of the Immergas group, which operates in 30 countries and has manufactured over 7 million boilers, Alpha benefits from some of the most advanced production facilities in the world.

This means you are guaranteed a high-quality combi boiler, despite the low prices. They offer a range of combi boiler sizes from the compact E-Tec to the larger E-Tec Plus, which deliver on every aspect.

Alpha Boilers are not quite the best combi boiler on the market but are an amazing budget option if cash is a little tight and you still want a solid boiler built to last.

Great budget boiler

Alpha Boilers is a budget option but manages to balance price with some reliable design decisions to give you a cheap but fairly consistent boiler line.

The Italian design, surprisingly useful parts, and labour warranties mean that each combi boiler will usually work fine in the long term.

A great set of sales and support staff also gives you an easy way to contact them if something goes wrong, and specific boilers have warranties of up to ten years, depending on the model you choose.

Alpha E-Tec Dimensions

Italian quality

While Alpha Boilers may be relatively cheap, they are not poor-quality, so they can become a great mid-range choice when you do not want to go too high or low.

Other than that, there is not much else to say about Alpha Boilers because they are a comfortable middle-of-the-road option that can fit into most homes and businesses without issue.

You are also covered for much longer than the price would suggest, so wear, and tear are not as much of a setback. If purchased through iHeat, you also get a massive 10-year warranty on all Alpha boilers.

Alpha Boiler Range

Alpha Model

Kilowatt (kW) Outputs

#

E-Tec

28

33

-

Get a quote

E-Tec Plus

28

33

38

Get a quote

Evoke

28

33

-

Get a quote

InTec

28

33

-

Get a quote

Alpha E-Tec Boiler

The E-Tec is ideal for small and medium-sized homes. The entire E-Tec range features brand-new stainless steel heat exchangers, making them highly robust, and they also have zinc-plated expansion vessels to prevent corrosion.

Taking these extra steps to maximise the longevity of your boiler life is what makes this range stand out. The E-Tec also has a high-efficiency pump which helps to deliver an impressive 14.1 litres of hot water per minute, and the single electrode drive charge is very easy to access, meaning your Alpha combi boiler will be easy to control and manage after installation.

Get your free fixed quote here.

Just some of the features of the E-Tec include:

  • 10 Year Warranty

  • Two available kW outputs

  • Combined condensate and pressure relief valve connection

  • Single Electrode

  • Easy-access dry-change NTCs on front of pipes

Alpha E-Tec Plus

The E-Tec Plus is similar to the E-Tec. Still, it is much larger and has a few extra benefits, such as a 10-year warranty, copper pipe tails with isolation valves, an integrated filling loop, a control panel, and a bottom cover.

This combi boiler is suitable for larger homes and offers a third higher output option than the E-Tec at 38kW

Alpha Evoke

The best combi boilers from Alpha are the smallest. Its compact size and layout are an ideal solution for small to medium-sized homes and has a stainless steel heat exchanger and many other amazing features such as:

  • 7 Year Warranty

  • Backlit LCD with push button controls and detailed operational information

  • High efficiency Grundfos pump and hydroblock assembly

  • Single electrode

  • Easy access for servicing

  • IPX4D protection

  • Low electrical consumption

  • Easy-access NTCs on front of pipes

  • One-piece cartridge diverter valve

  • Clip-on DHW temperature sensor

  • Dry-change NTCs

  • Combined condensate and pressure relief valve connection

  • Frost protection and daily pump kick

  • 14.1 litres of water per minute

Alpha InTec

The InTec combination boiler is different from the others due to its built-in GasSaver.

This combi boiler is perfect for anyone concerned about their environmental impact. The InTec reduces gas usage by 35% compared to other gas combi boilers and has a low electrical consumption.

Some of the useful features of the InTec are:

  • Same connections as a boiler with no additional exposed pipework

  • Isothermic stainless steel heat exchanger

  • High efficiency Grundfos pump and Hydroblock assembly

  • Backlit LCD with push button controls

  • Two available outputs

  • Easy-access NTCs on front of pipes

  • One-piece cartridge diverter valve

  • Clip-on DHW temperature sensor to prevent corrosion

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Some of The Best Boilers by Ideal

#4 Ideal Combi Boilers

In fourth place comes Ideal. This boiler brand is the best at small and affordable boilers, such as the Logic range and flashier pricier models, such as the Vogue range, catering for all their customers and their budgets.

Ideal Boilers has seen rapid growth over the last ten years, and offers a very simple warranty system that gives combi boilers either 2, 7, or 10-year warranties depending on which model you are buying.

Built to last

In terms of quality, they sit around the same level as Worcester Bosch but with a slightly lower price, which can make them more budget-friendly if you are trying to save every penny you can.

Of course, this price depends on the installer, so the cost of getting a combi boiler form Ideal Boilers can vary by location.

When compared side by side, they are a good alternative to Worcester Bosch, and many of their ranges are similar enough to stand in for WB combi boilers if you need them.

Looking for a mid-range boiler, then Ideal may be the Ideal choice 😉

Solid price

A mid-range price and a compact design ensure that these combi boilers can be used in various locations and situations, often knocking around 10% off the price compared to more expensive brands.

However, this comes at the cost of not necessarily having the same features, so that you may lose out on some unique benefits here and there.

Ideal Logic Plus Dimensions

Even still, Ideal combi boilers could offer you the best combi boiler depending on what you are looking for and how large your budget is.

They may be cheaper than other choices, but that does not make them worse or less reliable.

Ideal Boiler Range

Ideal Model

Kilowatt (kW) Outputs

Logic

24

30

35

Get a quote

Vogue Gen2

26

32

40

Get a quote

Vogue Max

26

32

40

Get a quote

Logic

Although the Logic combi boilers aren't as flashy as the rest of Ideal’s range, they’re reliable, compact and easy to use, earning The Queens Award in 2013 as well as The Good Housekeeping Award in 2013 and 2017.

Ideal offers a standard 2-year warranty that can be extended to 5 years, though with only a 3% chance of The Logic's best combi boiler breaking down, it looks like you won’t even need it.

Here are some of the features of the Logic boiler:

  • Large digital display

  • Easy to reach pressure gauge on front panel

  • Compact

  • Scratch resistant

Vogue Gen2

This is Ideal’s best combi boiler for its features and attractive design whilst remaining compact. It has a backlit 3.5” LCD full-colour display and has multi-function buttons for ease of use, built using premium components.

Endorsed by the Energy Saving Trust, you can be sure that this combi boiler is better for the environment. This boiler comes with a standard 8-year warranty.

Vogue Max

Ideal’s newest premium combi boiler has the same fantastic features and attractive appearance of the Vogue Gen2 with the addition of a high-quality Ideal System Filter, which boosts the warranty from 8 to 10 years.

Some of the other features include:

  • Easy to read pressure gauge

  • Premium components

  • Full-text support for fault modes

  • Stylish composite design with damped opening control cover and large rotary control dials

  • Service timer with telephone number/service display

A range of Combi Boilers by Vaillant

#3 Vaillant Combi Boilers

In third place is Vaillant, another Which? Best Buy Award winner. Vaillant is a premium contender and offers a 5-star boiler range for both small and large properties, though they do have premium prices which aren’t too friendly to your bank account.

However, they come with a convenient app to control your heating anytime, anywhere and have a 5-year warranty which can be upgraded to 7 or 10 years.

Valliant is rarely mentioned as often as other top brands. Still, they operate similarly to Worcester Bosch, combining great quality with various useful warranties and customer service options.

Warranties

Warranties generally sit between 2-5 years, depending on the model, with a price range similar to other beloved brands.

One of the main benefits of Valliant is the variety on offer: the ecoTEC combi boiler line has become a favourite for people who want lower energy consumption without losing performance, and the warranty can be upped to ten years with a Valliant Advance Installer.

The improved efficiency can help you save money, just like with Worcester Bosch combi boilers.

Customer Service

Finally, great customer service is always useful, and Valliant is keen to offer it. If something goes wrong and you need help fixing a problem or identifying a failure, then it is not hard to contact them, meaning that you will always have a way to contact the company and won't have to hunt down an obscure email address or phone number.

Vaillant Combi Boiler Range

Ideal Model

Kilowatt (kW) Outputs

ecoTEC exclusive

-

-

35

43

Get a quote

ecoTEC plus

25

32

35

38

Get a quote

ecoTEC plus store

-

-

--

38

Get a quote

ecoTEC pro

24

28

30

-

Get a quote

ecoFIT pure

-

25

30

35

Get a quote

Vaillant ecoTEC exclusive

This combi boiler is great for larger homes with higher outputs. It has the potential to generate an impressive 17.8 litres of hot water per minute and is eco-friendly and 85% recyclable. Like all Vaillant products, the ecoTEC exclusive has been approved by Quiet Mark, meaning it is one of the quietest products on the market.

Vaillant ecoTEC plus

This is the all-rounder of Vaillant’s combi boilers with the broadest range of kW outputs. It has precision heating to reduce fuel bills, delivers hot water within 5 seconds and has a 5-year standard warranty.

Vaillant ecoTEC plus store

This boiler is a powerful solution for larger homes with its high-performance control, efficiency and an integrated hot water storage device at the back of the boiler. Providing up to 20 litres of hot water per minute and hot water within 5 seconds, this combi boiler appeals to large families with a high demand for hot water and comes with a 5-year warranty.

Vaillant ecoFIT pure

The ecoFIT pure is another of Valliant’s highly efficient, smart control and high-performance combi boilers but much more compact to fit in a kitchen cupboard in a smaller home. This boiler comes with a less impressive 2-year warranty, but there is the option to increase this to 7 or 10 years for an extra cost.

#2 Viessmann Combi Boilers

In second place comes Viessmann. Viessmann surpasses most other combi boiler brands in the market with their advanced German engineering and efficient heating systems that are a great value for money.

Built to last

One of their key selling points is the longer lifespan, which makes their combi boilers last much longer than many competing products. Because of this, they will often appear near the top of any best combi boiler list.

Efficiency

Efficiency can mean a lot when it comes to heating, which often makes Viessman a good choice for keeping costs low in the long-run.

Even in designs with a lower maximum heat output, the improved efficiency can save plenty of money and better use the power you are already consuming.

Warranty

All of their models come with ten-year warranties when bought through iHeat, and there are simple finance options available for their more expensive offerings

Even better, most are designed to be silent or near-silent, making all the difference in a crowded home where the boiler can’t easily be tucked away.

Price

In general, Viessmann is a great choice for a smaller building, especially if you do not have as much room to store it.

The higher efficiency removes a lot of the hassle from setting the combi boiler up and means more power is packed into a single body.

You can fit a lot of them into existing cupboards or small alcoves, and the long-lasting design prevents them from breaking down easily.

Viessmann Boiler Range

Viessmann Model

Kilowatt (kW) Outputs

Vitodens 050-W

-

29

35

Get a quote

Vitodens 100-W

26

30

35

Get a quote

Vitodens 200-W

-

-

35

Get a quote

Vitodens 111-W

26

-

35

Get a quote

CDi Highflow

-

-

44

55

Get a quote

Viessmann Vitodens 050-W

The Vitodens 050-W 29kW, in particular, is the most reliable and has the highest quality with its stainless steel heat exchanger (which makes it extra robust), exceptionally quiet operation and an impressive water flow rate of 12 litres/min.

With compact dimensions and low weight, the Vitodens 050-W will integrate into any home without compromising quality. Winner of 2019 Which? Best Buy award, this combi boiler is Class-A rated for its energy efficiency and is easy to control with an LCD.

Viessmann Vitodens 050-W Dimensions

Here are just some of the amazing features this combi boiler has to offer:

  • 10 Year Warranty when purchased through iHeat

  • Integral instantaneous water heater

  • High efficiency of up to 97%

  • Low CO2 emissions for reduced environmental impact

  • Digital user interface

Viessmann Vitodens 100-W

This combi boiler has all the great features of the 050-W as well as extra features such as the extra 26kW output option and the user-friendly backlit LCD Touchscreen for easy operation. This boiler was endorsed by Which? and up to 94% of the fuel used is converted into heat, making it more environmentally friendly and Boiler Plus ready.

Viessmann Vitodens 100-W Dimensions

Viessmann Vitodens 200-W

If you’re looking for a combi boiler for a larger home, this boiler is for you. It has greater efficiency and lower emissions, with up to 98% of the fuel used converted into heat. Despite having to operate on a larger scale, this boiler remains compact and quiet thanks to its low-speed fan.

Viessmann have made this combi boiler incredibly easy to operate by incorporating a 7” colour touchscreen with an integrated WiFi interface for internet connection. It also has a new environmentally responsible MatriX-Plus burner which automatically adapts to the properties of different gas types to keep costs down and reduce the environmental impact of the boiler.

With its 10-Year Warranty, you can be sure you’ll have a long-lasting and reliable combi boiler.

Viessmann Vitodens 111-W

Viessmann describes its Vitodens 111-W as rapid, reliable and compact- and that it is, it's one of the best combi boilers that Viessmann offer. This combi boiler is perfect for large families with high hot water demand. With this high-performance wall mounted storage boiler, you can be sure there will be no more arguments in the morning about ‘who is using all the hot water?!’.

With the capacity to fill a bath in just 8 minutes, this combi boiler will never fail to provide the means for a relaxing soak. Here are some of the features that are bound to impress even those with minimal boiler interest:

  • 10 Year Warranty

  • Cylinder loading system (CLS) and integrated stainless steel storage tank

  • User-friendly control via backlit LCD touchscreen

  • High hot water capability of >18 litres per minute

  • Large range of outputs available

  • Optional wireless remote available

#1 Worcester Bosch (Our Best Boiler Brand Choice)

In first place come the Worcester Bosch boilers, the pioneers of combi boilers. In 2019, they secured a Which? Best Buy award for the 14th time.

Worcester Bosch is a huge household name in the boiler game for a reason.. reliability! 🏆

If you ask most people what the best combi boiler is, the Worcester Bosch group will always come up. Worcester Bosch covers many boiler types and features, which means they suit many situations.

However, they are also consistent in quality, so there is no risk of a certain model being extremely poor or unreliable.

Warranty

One of the biggest draws is their warranty offers. Depending on the exact boiler model you choose and the features included in the design, you can have a warranty of anywhere between five and ten years.

This means that with Worcester Bosch, you are covered in case something goes wrong, even if the fault only becomes obvious nine years after installation.

Even better, installing more Worcester Bosch products can extend this warranty: adding their filter system to one of their combi boilers can add another year to your overall warranty time, which means that you get even more protection if you gradually upgrade your new combi boiler during the existing warranty period.

Worcester Bosch Greenstar CDi Compact Dimensions

Price

Higher quality often comes with higher prices, and Worcester Bosch used to be a major example. Over time, though, some of their models have become much more affordable, and there are monthly payment options for people who can’t afford an up-front cost.

Getting Worcester Bosch combi boilers in 2024 can also be cheaper through third-party installers.

Worcester Bosch Boiler Range

Worcester Bosch Model

Kilowatt (kW) Outputs

Greenstar 8000 Style

30

35

40

45

Get a quote

Greenstar i (discontinued)

-

-

25

30

Get a quote

Greenstar 4000

25

30

-

-

Get a quote

Greenstar 2000

25

30

-

-

Get a quote

Greenstar Si Compact

-

-

25

30

Get a quote

CDi Classic

29

34

38

42

Get a quote

CDi Compact

-

28

32

36

Get a quote

CDi Highflow

-

-

44

55

Get a quote

Worcester Greenstar i (Now the Worcester Bosch Greenstar 4000)

The Greenstar i is Worcester Bosch’s most popular boiler that is ideal for small to medium-sized homes and has simple and easy-to-use controls; Worcester's new Greenstar 4000 range has since replaced this boiler. Here are some features of the Greenstar i:

  • Condensate discharge resilient to freezing up to -15?

  • Wide choice of controls

  • Low energy pump reduces electrical usage

  • Hot water instantly heated from cold mains

  • Achieves A-Rated efficiency

  • Fills a kitchen sink in 45 seconds

Worcester Greenstar Si Compact

This combi boiler has the same features as the Greenstar i but is much more compact to fit in a kitchen cupboard. It also has extra features such as frost protection and can fill a kitchen sink in 45 seconds.

Worcester CDi Classic

The Worcester CDI This is one of the more expensive combi boilers available but does guarantee reliability, fuel efficiency and a user-friendly interface. This combi boiler is suitable for many property types and sizes and is available in four heating outputs. Its modulating pump and intelligent controls also allow a 30% electrical energy reduction. It also comes with a 5-year warranty for peace of mind.

Worcester CDi Compact

This boiler is like the classic except much smaller to enable it to fit in a kitchen cupboard, making it ideal for smaller homes. It comes with frost protection, a user-friendly display and simple boiler controls to ensure you can manage your comfort and costs.

Worcester CDi Highflow

This combi boiler is an incredibly useful floor-standing combi boiler for large homes with many bathrooms. It provides high hot water flow rates of over 90 litres of draw-off. It has a wide choice of simple-to-use controls and a temperature display; however, with having such a large unit, a large space such as underneath a kitchen counter is required.

Honorable mentions

iHeat

At iHeat all of our subcontracted engineers are Gas Safe registered and can service your boiler swiftly and safely. Prices of an expert boiler service with iHeat start from £99.These figures might fluctuate regionally and can also depend on the specific type of boiler you own, such as a combi, gas, or oil boiler. 

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Combi Boiler Prices UK

Combi boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

New boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap

£1,845

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System to combi conversion

£2,499

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New boiler install

£2,899

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Back boiler to a combi

£3,299

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System to system

£1,945

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Frequently Asked Questions

What is the best combi boiler brand?

Choosing the best combi boiler brand depends on quality, reliability, and efficiency. Brands like Worcester Bosch, Vaillant, and Viessmann consistently top the charts for their exceptional performance and innovative technology. For example, the Worcester Bosch Greenstar 4000 and Viessmann Vitodens 100-W are praised for their energy efficiency and durability, making them a popular choice among homeowners.

Which combi boiler lasts the longest?

Longevity in combi boilers is often determined by the build quality and regular servicing. Top brands like Viessmann and Worcester Bosch are renowned for their robust models, which can last over 15 years with proper maintenance. Extended warranties offered by these brands, sometimes up to 12 years, reflect their confidence in the lifespan of their products.

How much does it cost to fit a combi boiler?

The cost of installing a combi boiler varies based on the model and complexity of the job. Typically, installation costs range from £2,500 to £4,000, including the boiler unit and labour. Replacing an existing combi boiler in the same location tends to be cheaper, while relocating or upgrading your system can increase costs.

Why are combi boilers being phased out?

Combi boilers are not being phased out entirely, but there is a push toward greener energy solutions. The UK government is encouraging the adoption of renewable heating systems like heat pumps to meet carbon reduction targets. While gas boilers remain widely used, transitioning to hydrogen-ready boilers or renewable systems is becoming more common to align with sustainability goals.

Can I replace my existing gas boiler after 2025?

Yes, replacing an existing gas boiler will still be allowed after 2025. The government’s focus is on reducing the installation of new gas boilers in newly built homes. For existing properties, you can still install gas boilers, but considering energy-efficient alternatives like heat pumps might help you future-proof your home and reduce your carbon footprint.

What is better than a combi boiler?

While combi boilers are excellent for many households, larger homes with high hot water demands may benefit from a system boiler with a separate cylinder. Renewable options like air source heat pumps are also gaining popularity for their energy efficiency and environmental benefits, though they may require higher initial investment and adaptations to your property.

Do I need new pipes for a combi boiler?

Whether new pipework is needed depends on your current system and the boiler’s requirements. If you’re replacing an older type of boiler, such as a conventional system, you might need to upgrade your pipes to handle the higher water pressure of a combi boiler. A professional heating engineer can assess your setup and make the necessary adjustments for optimal performance.

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Article by
Stephen Day

Co-founder

Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.