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Best Combi Boilers 2020 in the UK
Are you currently searching for the best combi boiler around?
Whether you’re planning ahead, or your current boiler has totally broken down, you’ve come to the right place. Our helpful will break down some of the best boilers available from top manufacturers in the UK. You’re in safe hands – we’ve considered everything from design, material quality, user accessibility and efficiency to make sure you know exactly what the benefits are!
In particular, we’ll focus on the following brands to give you all the information you need:
- Viessmann
- Worcester Bosch
- Vaillant
- Ideal
- Baxi
As well as this, we’ll also be including information on other boiler manufacturers including ATAG, Glow Worm, Alpha and Potterton, so watch this space!
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What’s the best combi boiler in 2020?
Here you’ll find reliable, fact-based reviews of the best combi boilers that 2020 has to offer.
It’s important to consider that the best combi boiler for you, depends on factors like your property type and user profile. This is why we’ve looked at several boilers for each manufacturer; to ensure you have options that are perfect for you and your property!
Let’s get cracking!
Best Viessmann Combi Boilers
There’s a lot of reasons why Viessmann are considered the top dogs of the domestic boiler industry. They know exactly what their customers need, and deliver excellent results.
Viessmann’s entire boiler range includes their very own patented Inox-Radial stainless steel heat exchanger, which in today’s age, means you can save a lot of money on your annual energy bills.
On top of this, the German manufacturer had gained extensive commercial heating experience before entering the domestic market, and consequently have many high-tech manufacturing facilities. This allows them to continually develop their boiler designs to make sure you get the best boilers possible.
Viessmann Boiler Breakdown
| Boiler Name | Output Range (KW) | Efficiency | Available Warranty |
|---|---|---|---|
| Viessmann Vitodens 200-w | 5.2-35 | Up to 98% (Hs) [Gross cv] | 3 years standard/10 years through Boilerhut |
| Viessmann Vitodens 100-w | 4.7-35 | Up to 98% (Hs) [Gross cv] | 3 years standard/10 years through Boilerhut |
| Viessmann Vitodens 050-w | 5.9-35 | Up to 97% (Hs) [Gross cv] | 10 years (Through Boilerhut) |
| Viessmann Vitodens 111-w | 4.7-35 | Up to 98% (Hs) [Gross cv] | 10 years (Through Boilerhut) |
Viessmann Vitodens 200-W
The Viessmann Vitodens 200-W is one of the best combi boilers in 2020 for many reasons. It’s made a habit of hitting the number 1 spot in many central heating reviews around Europe and the rest of the world, and with good reason. The 200-w is one of the best boilers in the UK’s domestic boiler market and manages to blow the competition out of the water in almost every aspect.
Viessmann Vitodens 200-W Key Features:
- 98% Energy Efficiency – almost all of the fuel used is converted into heat.
- 5-inch colour touchscreen. Easy to operate Vitotronic control unit.
- Can be controlled via a smartphone app and internet (with optional Vitoconnect 100 WLAN adaptor)
- Environmentally responsible MatriX cylinder burner
- High Quality Inox-Radial Stainless Steel Heat Exchanger
- Lambda Pro Control Plus Combustion Controller Ensures Consistently High Energy Efficiency
- Helps keep the maintenance costs down to reduce environmental impact
- Automatically adjusts to different gas types (Natural Gas, LPG, Biogas)
- Quietest boiler in the UK at only 34 decibels
- Compact dimensions, only 450 mm wide
- Pressure Release Valve and Condensate combined (Easy Installation)
- Energy Efficiency Class: A
- Optional remote fault notifications for Viessmann Trained Installers
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Viessmann Vitodens 050-W
In this Viessmann Vitodens 050-W Review, we look at one of the best and most affordable combi boilers you can buy in the UK. Don’t be fooled by its small price tag. This boiler can do everything its more expensive counterparts can do, and more.
Even at one of the more attractive price points in the UK, Viessmann offer their patented Inox-Radial Stainless Steel Heat Exchangers in this boiler. That alone is a major plus point in favour of the 050-W, because of how robust and highly efficient that heat exchanger is.
Watch our review of the 050-w below:
Viessmann Vitodens 050-W Key Features:
- Ultra Compact – Just 707mm in height
- DHW output ratings of 5.9 to 35 kW
- High quality stainless steel Inox-Radial heat exchanger
- Stainless Steel Cylinder Burner
- Integral instantaneous water heater
- Low CO2 emissions for reduced environmental impact
- Digital user interface with LCD display for easy operation
- Optional room thermostats, plug in time clock and wireless receiver
- Up to 10 year extended warranty available
- Class A rated for energy efficiency
To find out more about the Vitodens 050-W, click here to read our detailed review.
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Viessmann Vitodens 100-W
The Viessmann Vitodens 100-w is another example that stands among the best combi boilers currently available in 2020.
As a premium boiler, it’s positioned perfectly as a bridge between affordable combi boilers and the absolute, top-of-the-range premium.
If you thought any other boiler you’ve come across was a little pricey, the 100-w serves as an excellent alternative. It’s about £500 cheaper than the Vitodens 200-w, and boasts an energy efficiency of around 94% with programmable, smart controls and weather compensation.
Viessmann Vitodens 100-W Key Features:
- High Quality Stainless Steel Inox-Radial Heat Exchanger
- Environmentally responsible MatriX cylinder burner
- Backlit LCD Touch Screen for Easy Operation
- Class A rated for Energy Efficiency
- Pressure Release Valve and Condensate combined for easy installation
- Compact Design and low Weight
- Quiet operation with low fan speed
- Available in outputs from 4.7 to 35 kW
- Low CO2 emissions for reduced environmental impact
- Optional room thermostats available – Click here to read our Nest vs Hive article
- Up to 10 year extended warranty available
- LPG Conversion Kit Available
To find out more about the Vitodens 100-W, click here to read our detailed review.
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Viessmann Vitodens 111-W
Boasting a cylinder loading system and 46 litre integrated stainless steel storage tank, the Vitodens 111-W serves as a fantastic example of a boiler providing heat and hot water for customers who have a higher demand.
What is a Storage Combi Boiler?
Unlike a combi, system or regular/open vent boiler, storage combi boilers have a hot water cylinder housed within the unit itself. The benefit here, is that you save space by eliminating the necessity for a separate hot water cylinder or cold water storage tank. Everything is kept compact and easy to manage over the boiler’s lifespan, making the Vitodens 111-W an excellent boiler to recommend.
Key Features of the Viessmann Vitodens 111-W:
- Modulation ratio of up to 1:6
- Wall-mounted – allowing greater flexibility for boiler position
- User-friendly control via backlit LCD touchscreen
- Output availability ranges between 4.7 to 35 kw
- DHW (Domestic supply is equivalent to 150L unvented cylinder – due to the advanced CLS (Cylinder Loading System)
- Integration with smart thermostats such as Nest and Tado
- Sturdy casing
- Dimensions: 600 x 900 x 480mm
- 64kg Weight
- Energy Efficiency Class A
- Can be positioned in a number of rooms such as utility room or bathroom
- 46 litre capacity stainless steel integrated storage tank
Click here to read our review of the Viessmann Vitodens 111-W.
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Best Worcester Bosch Combi Boilers
Worcester Bosch boilers have become well-established as an example of excellent, award-winning design in the current boiler industry. With over 1 million homes using a Worcester Bosch boiler, their exposure is second to none compared to some other companies.
However, times can change, and so can the market. What was once the popular choice 10 years ago, may not be the same today. As a customer and a homeowner, you want to be able to get the best money-saving boiler option available.
Let’s take a look at how well Worcester Bosch achieves this goal…
Worcester Bosch Boiler Breakdown
| Boiler Name | Output Range | Efficiency | Available Warranty |
|---|---|---|---|
| Greenstar CDi Classic | 7.7 - 30 | Up to 90.2% | 5 years |
| Greenstar i | 24 | Up to 89.8% | 5 years |
| Greenstart 8000 Style | 3.1 - 35 | Up to 94% | Up to 12 years |
Worcester Bosch Greenstar CDi Classic
As mentioned, Worcester Bosch has been the market leader in the UK for many years now, and with good reason. They rank high in consumer satisfaction reports, and remain one of the best boiler manufacturers for 2020.
Unfortunately, while many competitors have made the wise choice to switch to stainless steel for their heat exchangers (an extremely important component), Worcester Bosch have kept their original option, Aluminium. While this is great for thermal conductivity to begin with, it’s much more prone to corrosion, and has a drastic negative effect on your property’s central heating and your wallet.
Key Features of the Worcester Bosch Greenstar CDi Classic:
- Highest hot water flow rate of the Greenstar combi wall mounted range
- Simple boiler control knobs with clear temperature display
- Low energy pump reduces electrical usage
- Frost protection is included, reducing frost risk if installed in a garage or a loft
- Larger two bathroom properties can be supplied by higher output options
- Wide choice of controls enables greater comfort and economy
- Instantaneous hot water, always available
- Inbuilt keyless filling link making it easy to refill your system
- Large Condensesure style siphon built into the boiler – eliminates frost risk*
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Worcester Bosch Greenstar i
The Greenstar i is Worcester Bosch’s more affordable option. Its design allows for simple controls and function, and gets the job done. Having said that, there are perhaps better boiler installation options to go for for the same price, if not cheaper.
Key Features of the Worcester Bosch Greenstar i:
- Simple boiler controls with clear information display
- Condensate discharge resilient to freezing up to -15’C* **
- Wide choice of controls enables greater comfort and economy
- Low energy pump reduces electrical usage
- Hot water instantly heated from cold mains
- Achieves an A+ ErP package efficiency rating for heating when installed with a Wave smart internet connected control
Worcester Bosch Greenstar 8000 Style
This powerful boiler from Worcester Bosch features a brand new design catering much more to the modern market. It’s capable of delivering up to 50kw, which makes it one of the most powerful wall hung boilers available.
Key Features of the Worcester Bosch Greenstar 8000 Style:
- LPG model available
- EasyControl Compatible
- 780 x 440 x 365
- Central heating output 30-35kw
- Hot water flow rate 40°C 10.7-14.3 l/min
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Best Vaillant Combi Boilers
Along with Worcester Bosch, Vaillant have proven themselves to be strong competitors in the UK market for many years now. As a result, they’ve used this experience to become a top manufacturer, creating front-running products in the industry.
One of Vaillant’s strengths is their development and focus on systems that utilise sustainable energy sources. With high efficiency ratings and low emissions, they’re proved themselves to be a great choice.
Vaillant Boilers Breakdown
| Boiler Name | Output Range (KW) | Efficiency | Available Warranty |
|---|---|---|---|
| ecoTEC Plus Combi | 25 - 38 | Up to 89.3% (SEDBUK) | 5 years (standard) |
| ecoTEC Exclusive Green iQ | 35 - 43 | Up to 89.7% (SEDBUK) | 5 years (standard) |
| ecoTEC Plus Combination Store | 38 | Up to 89.3% (SEDBUK) | 5 years (standard) |
Vaillant ecoTEC Plus Combi
Alongside Viessmann, German manufacturer Vaillant has been operating in domestic boilers for many years. While many of the boilers in their range still use an Aluminium heat exchanger (which definitely has its fair share of negatives), the ecoTEC Plus Combi uses stainless steel. Because of this, many put Vaillant above Worcester Bosch – they simply know what makes a good boiler.
Key Features of the Vaillant ecoTEC Plus Combi:
- Stainless Steel Heat Exchanger
- High performance, control and efficiency
- Precision heating to reduce your fuel bills
- A wide range of heating control options, from a simple boiler timer right up to the vSMART™ smartphone app
- Delivers hot water within 5 seconds (and no need for a storage tank or cylinder.)*
- 5-year guarantee as standard, with 7 to 10 years available when you book a Vaillant Advance installer
- Four combination models covering 25, 32, 35 or 38kW heating outputs
- A flow rate of up to 15.9 litres per min for fast hot water*
- ErP A rated for both hot water and heating efficiency
- Dimensions in mm (825 model): H 720 x W 440 x D 338
- Works with LPG where required
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ecoTEC exclusive with Green iQ Combi Boiler
This boiler is one of Vaillant’s most eco-friendly, with 85% of its parts being recycled once it’s reached the end of its life. It’s also compatible with vSMART control, so you can take control from your phone or tablet.
Key Features:
- Two combination models covering 35 or 43kW output
- A flow rate of 17.8 litres per min for fast instant hot water
- ErP A rated for both hot water and heating efficiency
- Dimensions in mm (43kW): W 720 x H 440 x D 474
- Works with LPG where required
ecoTEC plus combination store
This boiler is one of Vaillant’s most eco-friendly, with 85% of its parts being recycled once it’s reached the end of its life. It’s also compatible with vSMART control, so you can take control from your phone or tablet.
Key Features:
- Two combination models covering 35 or 43kW output
- A flow rate of 17.8 litres per min for fast instant hot water
- ErP A rated for both hot water and heating efficiency
- Dimensions in mm (43kW): W 720 x H 440 x D 474
- Works with LPG where required
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Best Ideal Combi Boilers
Ideal Boilers first began way back in 1906. As they entered the 1920s, they began to take boilers from basements, and move them into the familiar kitchen area that many of us are used to today. As a result of this extensive experience, they have proved themselves as prioneers in high-efficiency technologies.
With a focus on customer usability, Ideal are continually developing their products while retaining their key principles – quality, innovation and value.
Today, they manufacturer maintains a reasonable share in the UK market, scoring highly on many Ideal boiler reviews for those of us who want something affordable and reliable.
Ideal Boiler Breakdown
| BOILER NAME | OUTPUT RANGE (KW) | EFFICIENCY | WARRANTY |
|---|---|---|---|
| Ideal Vogue Combi | 26, 32 and 40 | 91.1% | 7 years standard |
| Ideal Logic+ Combi | 24, 30 and 35 | 94% | 2 years standard |
| Vogue Max Combi | 26, 32 and 40 | 93% | 10 Years |
Ideal Vogue Combi
The Vogue is Ideal’s premium offering, with particular focus on improve the design of the boiler itself. There are three different outputs available for this range (26, 32 and 40). The first and last of which have an efficiency rating of 91.1%, while the 32KW has an efficiency rating of 91%. While there are others on this page with better efficiency, this could still potentially save you money.
Key features of the Ideal Vogue Combi:
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Ideal Logic+ Combi Boiler
The Logic+ Combi from Ideal is a solid choice for those of us looking to replace our current boiler with something more efficient. With a compact size, it can also fit neatly into a typical kitchen cupboard.
Known for its quiet operation, it does a good job of working silently in the background. With a decent warranty length (7 years), it’s a certainly a good choice – but you’ll have to work hard finding an installer with a close relationship with the manufacturer in order to get anything better.
Key features of the Ideal Logic+ Combi Boiler:
- Made in the UK
- Queen’s Award in 2013 for Enterprise and Good Housekeeping
- Fits neatly into most cupboards
- Good Housekeeping 2013 and 2017
- Built-in frost protection
- Energy Saving Trust endorsed
- 7 year warranty* & 10 year warranty on heat exchanger
Vogue Max Combi
The Vogue Max Combi boiler is Ideal’s more recent entry in the premium market. By combining the benefits of the Vogue Gen2 along with a system filter, Ideal do their best to give you everything you need. If you’re willing to throw a lot more money towards your heating, this might be worth a look, but prepared for a high price tag.
Key Features of the Vogue Max Combi Boiler:
- Pressure gauge is easy to read
- Compatible with Ideal controls
- Fault modes accompanied by full text support
- Accessible user interface with a 3.5in colour LCD display
- Stylish design with simple cover over controls and large dials
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Best Baxi Combi Boilers
Baxi have been operational for over 150 years. The Baxi Bermuda back boiler was hugely successful and was discontinued recently. Baxi are a solid company with a rich history and a century and a half of experience. They employ about 6,400 people throughout Europe. Baxi are, without a doubt, a well known brand name in the UK, and are now expanding to other parts of Europe.
Baxi is one of the biggest combi boiler manufacturers in the UK. Its range of EcoBlue, Duo-tec, Megaflow and Platinum combi boilers come in sizes to suit almost any size and type of home, and they range in price between £650 and £1,200. But are Baxi boilers reliable? And what do expert heating engineers make of them? Head over to our Baxi combi boiler reviews to find out if it’s worth investing in a Baxi or if other boiler brands are a better bet.
Baxi Combi Boiler Breakdown
| BOILER NAME | OUTPUT RANGE (KW) | EFFICIENCY | WARRANTY |
|---|---|---|---|
| Baxi 200 Combi | 24 and 28 | 89% | 5 years standard |
| Baxi 400 Combi | 24 and 28 | 89% | 5 years standard |
| Baxi Duo-tec Combi | 4, 28, 33 and 40 | 88.6% | 7 Years standard |
Baxi 200 Combi
Baxi have been known as a popular brand in domestic boilers, largely because of the consistency of their boiler range. While not being revolutionary, Baxi boilers offer homeowners a decent choice for a boiler replacement. Much like their competitors, they’ve designed their boilers to fit nicely into most kitchen cupboards.
Baxi 200 Combi Key Features:
- Available in outputs 24 and 28kW
- Only available from independent merchants
- Simple hanging bracket
- Choice of flue lengths
- Compatible with uSense smart control
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Baxi 400 Combi
Much like the 200 series, the Baxi 400 Combi boiler is an example of a typical modern condensing gas boiler that can fit in your kitchen cupboard. With ‘A’ rating for efficiency and smart room thermostat capabilities, you can stay in control of the temperature.
Baxi 400 Combi Key Features:
- Available in outputs 24 and 28kW
- Stand-off frame optional
- Choice of flue lengths
- Compatible with uSense smart control
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Baxi Duo-tec Combi
Baxi’s Duo-Tec is a condensing gas combi boiler that’s more suitable for medium to larger homes. With features such as the built-in frost thermostat and uSense smart control – the Duo-Tec can achieve an efficiency rating of up to 88.6%. While not as high as some competitors, they still show an commendale focus on effiency and lowering those energy bills.
Baxi Duo-tec Combi Key Features:
- Available in outputs 24, 28, 33 and 40kW
- Flow rate up to 16.4 l/min
- Full wall mounting jig
- Various flue lengths available
- Compatible with uSense smart control
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How to choose your next boiler
As we’ve shifted into another year, there have now been more combi boiler options than ever before. While this is scary and overwhelming to some, it means that ultimately, you’re in control.
Because of this however, it’s easy for customers to immediately go for the cheapest boiler option such as Ferroli, Biasi and Alpha. This doesn’t necessarily mean these are bad boilers, but they may not serve the money-saving purposes that you’ll need – especially considering how the Coronavirus has affected us.
Ideally, you want your next boiler to be able to get through 15-20 winters without any issues, so make sure you choose a reliable manufacturer like Viessmann or Worcester Bosch to get it done.
Along with the manufacturer, it’s also a good idea to choose a premium, high-quality installer with a good working relationship – one knows what they’re doing. You’ll save yourself the hassle further down the line, and it’ll be worth it in the end.
If you stick with your old boiler, over the next few years you could end up losing a lot in frequent repairs, or the low efficiency will cost you money on energy bills. That’s where a new combi boiler comes in. Even if you’ve already had an idea which combi boiler is best in 2020, there’s nothing wrong with getting a better idea before making a final purchase.
Which combi boiler is best?
We’re all aware of how fast technology can evolve. That’s why if we’re asking ‘Which Boiler is best in 2020?’, there are a few things to consider that may not be obvious. Because modern condensing boilers can be similar in many cases, it’s important to understand the differences and details.
For more information on which boiler is best, click here.
What’s the best combi boiler for a flat or 1-2 bedroom property?
If you have a reasonably small property with around 1 or 2 bathrooms or a flat with one bathroom, you won’t need a high capacity boiler to meet your demands. With a combi boiler you can enjoy all the saved space thanks to the lack of a cold water storage tank or hot water cylinder.
Winner: Viessmann Vitodens 100-W
On top of becoming a recipient of Which? Best Buy for several years running, the Vitodens 100-W is proof that Viessmann know exactly what they’re doing in 2020.
Think you know which boiler you want? Get a quote by entering your postcode below!
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What’s the best combi boiler for a 3 bedroom property?
A typical 3 bedroom house will have 1 bathroom, with an additional ensuite and toilet if necessary. A slightly higher capacity boiler between 29-35kw will be sufficient for a property of this size.
You also have the option of a storage combi boiler. These combi boiler alternatives have a built-in hot water storage tank. This means that depending on your mains water pressure, a product like the Viessmann 111-W Storage Combi Boiler can give you up to 20 litres per minute easily.
Winner: Viessmann Vitodens 111-W Storage Combi Boiler
As mentioned above, the Vitodens 111-W serves as an excellent choice for providing you with the hot water you need.
What’s the best combi boiler for a property with more than 4 bedrooms?
If you’re the owner of a larger home with more bedrooms, the demand for hot water will naturally go up along with it. We can’t recommend a small capacity combi boiler to be installed in this kind of scenario, as it won’t be able to cope with the multiple showers, taps and appliances being used at the same time.
However, as we’ve mentioned above, there are some high capacity storage combi boilers that can also be suitable.
Winner: Viessmann Vitodens 111-W Storage Combi Boiler
What’s the cost of a new combi boiler?
The fact is, getting a straight answer for this question immediately can be tricky. Although the typical price for a new combi boiler could be anywhere between £1,500 to £3,500, the best way to move forward is to speak with a heating professional like Boilerhut to determine your current situation and identify the ideal boiler.
Want to know how much a new combi boiler costs to install? Click here to find out.
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Are there other options if I don’t have an LPG/Gas boiler?
There are some of us in the UK (around 15%) that aren’t connected to the mains gas network. They have to seek alternative means of energy to supply the heating in their home. For these people, their other options include:
- Heating Oil
- LPG
- Electric
- Heat Pumps (Ground Source)
- Biomass Boiler
- Solar Panels
Fortunately, all the best combi boilers from 2020 we’ve listed above work with both mains natural gas and LPG. With just a simple conversion kit – which you can find at all plumbing merchants – this issue can be solved quickly. More specifically, the Viessmann Vitodens 200-W model doesn’t need an LPG conversion kit, because it adjusts to different fuel types automatically.
Electric boilers may be fairly cheap to install but extremely expensive over the long term. Other options like heat pumps, biomass boilers and solar panels are energy efficient in the long term, but very expensive to install initially.
With all this considered, lets take a quick look at oil boilers along with their current availability to help you decide which boiler is best.
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Combi Boiler Alternatives
Even after all the boilers you see listed above, there are still more options available. On top of the usual best combi boilers 2020, and because of rising space saving and energy saving demands, we also have storage combi boilers available now. For the most part, storage combi boilers are similar to standard combi boilers, but the main difference is that storage combi boilers come with an integrated hot water tank.
As an example, a storage combi boiler installation such as the Viessmann Vitodens 111-W can supply hot water at a rate of up to 18 litres/min for larger properties with 2 bathrooms without any issues.
For further information on the best combi boilers 2020 with a tank, read one of our previous blog posts by clicking below:
What is a Combi Boiler?
What does ‘Combi Boiler’ mean?
Combi is short for “Combination”.
A detailed guide on best combi boilers is available on our website if you want to learn more.
Don’t panic if you’re worried about fuel at this point, a ‘combi boiler’ is just one ‘type’ of boiler currently available, and doesn’t relate to the fuel itself. For example, you may have a gas boiler but it could still be a combi, a sealed system boiler or a regular (open vent) boiler.
In brief, a combi boiler combines heating and hot water into one single unit. This is one of their main benefits – using high-quality internal components and excellent design, all the best combi boilers are able to produce heat for your home using a lot less energy. Unlike an installation for conventional/regular or sealed system boilers, they don’t require a separate hot water storage cylinder to store or heat/reheat water. It simply heats water on-demand as and when you require it.
All modern boilers manufactured in the last 12-15 years (whether a combination boiler, regular or system) are condensing boilers.
While the best combi boilers 2020 will save you space and energy, they’re limited in the fact that when it comes to a larger property with multiple bathrooms, they may struggle to deliver on hot water demand from multiple taps.
How do Combi Boilers work?
Central Heating
As you can see in the cross-section diagram of a combi boiler above, it has two heat exchangers; a primary heat exchanger and a secondary plate heat exchanger.
Inside all the best combi boilers 2020, the primary heat exchanger heats incoming mains water that then goes through the pipes into your radiators, heating them up. That hot water travels through the radiators and returns to the boiler.
Because that water has gone through the radiators, it collects sludge and grime and becomes dirty and undrinkable. How does a combi boiler deliver clean, hot drinking water?
DHW (Domestic Hot Water)
The dirty water returning from the radiators is used as a heat source to heat up clean drinking water inside sealed pipes via the secondary plate heat exchanger. What facilitates this for best combi boilers 2020, is a small but important component called a diverter valve.
So, every time you open a tap in your house and call for hot water, the combi boiler pauses the central heating and opens the diverter valve to bring you hot drinking water.
This is why you hear the boiler clicking every time you open a tap and call for hot water.
Want to know more about your combi diverter valve is? Click here to read about what they are and what they do.
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Why is the quality of a boiler’s components important?
A lot of people in the UK look at boilers only in terms of brand names instead of doing deeper research to find out if there are better options available.
Market leaders also usually have the biggest budget to sway reviewers or independent consumer research magazines.
It is surprising that while Which? Magazine ranks best combi boilers 2020 taking everything else into consideration, they don’t talk much about internal components, especially heat exchangers.
We’ve had customers who wouldn’t buy anything else than Worcester Bosch because:
- That was their previous boiler.
- Their plumber buddy recommended it.
- Their friend/family member recommended it.
Then we’ve also had customers calling us to replace a 6 year old Worcester Bosch boiler simply because of low efficiency or a damaged/blocked heat exchanger with debris and sludge.
Then we have strategically clever customers like you researching best combi boilers 2020 and reading this post to make an informed, educated decision.
Stainless Steel vs Aluminium Heat Exchangers
Many established brand names in the UK still use aluminium heat exchangers sourced by a third party based in France for their combi boilers. This helps them keep the manufacturing costs down and keep selling their product riding on national reputation, brand name and word of mouth advertising.
What’s the best material for my boiler’s heat exchanger?
Stainless steel is extremely resistant to corrosion in a wide range of pH levels. Whereas for aluminum, if the special manufacturer-recommended heat transfer fluids and inhibitors are not used to produce and maintain a narrow pH range, it will corrode much faster and get damaged.
And if you do damage the heat exchanger, your warranty will be voided, because the manufacturer will cite improper use of fluids.
In direct comparison, stainless steel heat exchangers do not require special fluids, are compatible with plain clean water and propylene glycol (commonly available). Ideal for best combi boilers 2020.
Please take a look at the diagram below which compares stainless steel with aluminium heat exchangers:
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As you can see, aluminium starts off great, but drops off massively after the first 1000 operating hours. The environment inside a boiler is like a furnace and puts extreme thermal stresses on the internal components on a daily basis, and 24/7 during the winter months.
Which is why you want the most durable metal inside your boiler. While aluminium is lighter in weight and has higher thermal conductivity, in terms of durability and corrosion resistance, it can’t hold a candle to stainless steel.
Why have we ranked Viessmann boilers higher than other brands?
Now that you’ve seen what some of the best gas combi boilers have to offer, as we’ve proven above, there’s no doubt stainless steel is a better metal for a boiler’s heat exchanger. Especially if you’re looking at this as a longer term investment towards the energy efficiency of your home.
Viessmann’s entire boiler range has their patented inox-radial stainless steel heat exchanger inside them, which earns them big points in the race for best combi boilers 2020.
And because Viessmann have extensive commercial heating experience before they jumped into the domestic boiler market, they already have high tech manufacturing facilities. Their heat exchanger is manufactured in-house at Viessmann’s factory, which helps them save on the sourcing costs and compete against the more established brands in the UK.
Inox Stainless Steel is an alloy with a minimum of 10.5% chromium content by mass and a maximum of 1.2% carbon by mass. Higher chromium content makes stainless steel resistance to corrosion and staining, and low maintenance, making it THE most ideal material for a heat exchanger for best combi boilers 2020. It remains durable and doesn’t lose efficiency for the life of a boiler. Whereas aluminium corrodes and drops down in efficiency within just a few years.
Why is Durability Important for Energy Efficiency?
Two boilers start off at the same efficiency, let’s say 92%. One has aluminium, and the second has stainless steel heat exchanger. Aluminium corrodes after a few years and drops down in efficiency to 85%. Stainless steel meanwhile hasn’t corroded, retains its efficiency and remains at 92%.
Energy efficiency of 92% for a new boiler installation means you’re converting 92% of the fuel into heat, and only losing 8%. In monetary terms that means for every £100 you spend on energy, you’re losing only £8. And for a boiler at 85% efficiency, you’re losing £15 on every £100 you spend on energy. That extra £7 lost adds up over time.
In the diagram below you can see a stainless steel heat exchanger on the left, and a corroded aluminium one on the right. The internet is littered with complaints about aluminium heat exchangers getting damaged due to debris and sludge.
Best combi boilers 2020 listed in this post are about the same price for boiler installation. So, it’s an absolute no-brainer to choose one with a stainless steel heat exchanger. We simply cannot see any advantage of going with aluminium. It doesn’t matter if the boiler carries brand reputation or any other fancy bells and whistles.
How do I get a combi boiler installed?
If you’re read through this information and decided that a combination boiler is right for you, you can start moving forward.
Whether you’ve specifically chosen which combi boiler to have installed, or you’re still deciding which of the boilers for sale you’d like, speaking to a industry expert can help you find that valuable support and reassurance you need.
At Boilerhut, we can give you the information you need as well as answer any questions you may have to ensure you have a combi boiler that’s perfect for you and your property.
To do so, you can either contact us directly by calling us on 029 2009 9898, or get a free, no-obligation quote from Boilerhut by entering your postcode in the box below, then click the green button.
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