which boiler is best 2019

Which Boiler is Best in 2019

Technology evolves at light speed, and when we ask the question Which Boiler is Best in [insert year], we get vastly different answers every year.  Because modern condensing boilers can be so similar, every little detail counts.  Which is where internal components and their quality come to the fore.  Before we delve deeper into the best boiler brands in the UK, quality of internal components and which boiler is best in 2019, let’s first explain what are the types of boilers available.

Types of Boilers – Which Boiler is Best for You?

Combi Boilers

which boiler is best 2019, combi boiler

Short for Combination Boiler, these don’t need extra storage tanks, and provide heating and hot water directly from the boiler.  If you haven’t got a large house with many bathrooms, then a combi boiler may be the best option for you.  Combi boilers are also generally cheaper and easier to install, which saves you money and time upfront.

If you are new to the world of combi boilers, we’ve published easy-to-understand guides on our blog which may help:

What is a Combi Boiler?

How a Combi Boiler Works

Which boiler is best when it comes to combi boilers?  This post may help: Best Combi Boilers in the UK

Conventional Boilers

which boiler is best 2019, conventional boilers

These are also called standard boilers.  The technically accurate term is “Open Vent Boilers”.  Conventional or standard boilers require a cold water tank in the loft, and a hot water cylinder elsewhere in the house.

Which boiler is best if your house has more than 2 bathrooms, and hot water may be called simultaneously?  A conventional boiler may suit you best.

Sealed System Boilers

which boiler is best, system boilers

The heating and hot water components are built into the boiler.  It needs a pressurized unvented cylinder for storing hot water.  Unlike a conventional boiler, you don’t need a cold water tank in your loft or attic.

Which Boiler is Best for Your House?

No single type of a boiler is best in all situations.  Combi boilers are best for smaller properties, and standard/conventional and system boilers suit larger homes.

When you’re in the market for a new boiler, the most important decision is obviously choosing the right boiler size for your house.  Which, again, depends on the size of your house and the number of bathrooms, which will determine your heating and hot water requirements.  What’s great with modern condensing boilers is that even if you buy a larger capacity boiler, they will modulate energy usage between 5kW and 30kW depending on the load.

However if you’re moving from a flat to a detached house, your old boiler will not work in your larger new home.

Let’s take a look at the types of boilers suitable for your property type:

Flat/1-2 Bedroom House – 1 Bathroom

which boiler is best for a flat

If your property size is small, say a house with 1-2 bedrooms, or a 1 bedroom flat, with no more than 1 bathroom, which boiler is best?

You don’t need a high capacity boiler.

Whilst you may have a system boiler, and do not want to change, we would still recommend conversion to a combi.  For two reasons.  Save space, and save energy.  How does a combi boiler save energy?  Because it only heats the water on-demand or when needed.  A system or regular boiler store water in an unvented cylinder and have to reheat it multiple times to keep the water hot.

Below are the best boilers in this category:

BrandModelOutput (kW)PRICEFuel
ViessmannVitodens 100-W Combi26£1,042.20 inc. VATGas/LPG
Worcester BoschGreenstar 25i Combi24£911.98 inc VATGas/LPG
VaillantecoTEC pro Combi24£976.32 inc VATGas/LPG
Grant UKVortex Eco External System 21-2626£2,465.31 inc VATOil
ViessmannVitodens 050-W29£825.60 inc VATGas/LPG

Please note: The prices above are from an online plumbing wholesaler for the boiler only, and do not cover installation costs or other extras.

Boilers listed above are mains gas boilers, and can be used for LPG with a conversion kit.  Then there are high end, premium, technologically advanced boilers like the Viessmann Vitodens 200-W which can adjust to any fuel type, mains gas or LPG, automatically.  This boiler ticks all the boxes when it comes to answering the “Which boiler is best?” question.

Because combi boilers provide heating and hot water “on-demand” and don’t require additional water tanks, they are not suitable for larger properties with more bathrooms.  Where there may be a chance of 2 or more people calling for hot water at the same time.

Semi-Detached, Mid or End Terraced House – 3 Bedrooms – 2 Bathrooms

which boiler is best for a semi detached house

Which Boiler is Best?

A 3-4 bedroom house will usually have one bathroom, an en suite and maybe a toilet.  A higher capacity (28KW  to 35KW) powerful combi boiler should work well for a property of this size.

A new, energy efficient conventional or regular boiler (18kW-24kW), with a water tank, is also an option.  It is best to talk to a heating expert for the best advice for your situation.

Fortunately it’s 2019, and there are storage combi boilers available for larger properties.  What is a storage combi boiler?  It’s a combi boiler with an in-built hot water storage tank.  Depending on your mains water pressure, a Viessmann 111-W Storage Combi Boiler can give you up to 20 litres per minute easily.

These are our recommendations of the best boilers for an average 3 bedroom house in 2019.

ViessmannVitodens 111-W Storage Combi Boiler26£1,516 inc. VATGas/LPG
ViessmannVitodens 100-W Combi Boiler35£1,200 inc. VATGas/LPG
Worcester BoschGreenstar Highflow 440CDi Floor Standing Combi Boiler29£2,109 inc. VATGas/LPG
VaillantecoTEC plus 938 Storage Combi Boiler38.7£1,571 inc. VATGas/LPG
ViessmannVitodens 200-W Combi with Weather Compensation (98% Efficiency)30£1,515 inc. VATGas/LPG
ViessmannVitodens 050-W Combi Boiler35£870 inc. VATGas/LPG
GrantVortex Eco External System 26-3526£2,169.17 inc VATHeating Oil

Please note: The prices above are from an online plumbing wholesaler for boiler only, and do not cover the installation costs or any extras.

Again, all boiler models shown above can be used for Gas or LPG (with a conversion kit).  The only two exceptions are Grant (Oil Boiler), and Viessmann Vitodens 200-W which don’t require an LPG conversion kit, because it adapts to different fuel types automatically.

Detached House/Bungalow – 4+ Bedrooms – Multiple bathrooms

which boiler is best for a large house

Which Boiler is Best?

Obviously, as your house size goes up, so will your heating and hot water demands.  Which means a more powerful boiler is required to heat and provide hot water to your larger property.

Which boiler is best for a larger house?  We do not recommend a small capacity combi boiler for a property this size.  No heating expert will, because small capacity combi boilers simply won’t be able to cope with multiple showers, taps and appliances at the same time.

However as we’ve mentioned earlier, there are some high capacity storage combi boilers that may be suitable.

Our recommendations for the best boilers for a larger detached house, bungalow with more than 4 bedrooms and more than 3 bathrooms are:

ViessmannVitodens 111-W Storage Combi Boiler35£1,743 inc. VATGas/LPG
ViessmannVitodens 100-W Open Vent35£1,319 inc. VATGas/LPG
Worcester BoschGreenstar FS 30CDi Regular30£1,532.27 inc. VATGas/LPG
VaillantEcoTEC Plus 438 Open Vent38£1,582 inc. VATGas/LPG
GrantVortexBlue Internal Sealed System 2636£2,370 inc. VATOil
ViessmannVitodens 222-F Floor Standing Storage Combi Boiler35£2,850 inc. VATGas/LPG
ViessmannVitodens 242-F Floor Standing Storage Combi Boiler (Solar Integration)26£4,748 inc VATGas/LPG

Please note: The prices above are from an online plumbing wholesaler for boiler only, and do not cover the installation costs or any extras.

What are Floor Standing Storage Combi Boilers?

You may have noticed we recommended two large Viessmann floor standing storage combi boiler models in the table above.  These are space saving innovations from Viessmann so you don’t require an additional unvented cylinder.

Furthermore, these boilers have what’s called CLS (Cylinder Loading System) technology.  When we’re talking about which boiler is best, these boilers are definitely top of the pile.

Most unvented cylinders that work with a regular or system boiler use a heating coil to heat up the cylinder.  The CLS technology replaces the coil with a plate heat exchanger.  A DHW (domestic hot water) pump circulates the cold water from the bottom of the cylinder, through the plate heat exchanger and puts the hot water back to the top of the cylinder.

All of this happens much faster than your conventional cylinders because of the CLS technology.  Which is why a 100 litre cylinder with CLS gives the same performance as a 200 litre unvented external cylinder.  So when you ask which boiler is best for a larger property without installing an extra tank, this is the answer.

The cross-section diagram below explains things in more detail:

which boiler is best, floor standing storage combi boilers

Best UK Boiler Brands in 2019

Now that we’ve looked at which boiler is best for your property type, let’s take a look at best boiler brands in the UK.  The list below is in no way in order of preference.  All the boiler brands listed below are established manufacturers in the UK with great reputation.

Boiler manufacturers like Viessmann, Worcester Bosch and Vaillant are trusted names not just within the UK and Europe, but all around the world.  They are known as premium, top of the line boiler brands.

Whereas brands like Ideal, Baxi and Glow Worm etc. fall in the affordable or cheap boiler category.

So, do we have a definite answer for which boiler is best among the ones listed above?  Not really.

We believe we have given you enough relevant facts and information in this post, so you can make an educated, informed decision.  At the end of the day, the decision to buy a boiler should be driven by facts, figures, unbiased reviews over personal preference.

A lot of people make emotional decisions based on national pride, old reputation or word of mouth opinions not backed up by facts.

Having said all of that, there are always subtle differences below the surface which make some boiler brands stand out from the crowd.  Our job is to illustrate those differences and make the buying decision easier for you, so that it’s clear which boiler is best.

Why Boilerhut Chose to Work with Viessmann

You may have noticed we’ve recommended Viessmann plenty of times in this post.  There are many reasons for that.  Even if we didn’t have a close working relationship with Viessmann, we will still recommend them when you ask which boiler is best, simply because we prefer to go by facts.

Furthermore, we like to help our customers with the best information possible, so that there are fewer complaints over the long term.  When you ask which boiler is best in 2019, we believe Viessmann are the best boiler brand in the world for a couple of reasons:

1. Patented Inox-Radial Stainless Steel Heat Exchanger (Manufactured In-House)

which boiler is best 2019, stainless steel heat exchanger

This is what separates Viessmann from other boiler brands in the UK.  It’s patented and manufactured in-house, which helps Viessmann keep the costs down.

Inox Stainless Steel with 10.5% chromium content and 1.2% carbon by mass is vastly superior to aluminium for a heat exchanger.  The chromium content makes it highly resistant to corrosion in a wide range of pH levels.

Whereas for aluminum, if the proper fluids are not used to produce and maintain a narrow pH range, it will corrode much faster.  Without the use of proper fluids, you can damage an aluminium heat exchanger.  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 commonly available propylene glycol.

Stainless steel’s resistance to corrosion and staining, and low maintenance, make it an ideal material for a heat exchanger inside a boiler that has to go through furnace-like thermal stresses on a daily basis.

Which boiler is best?  The one with a stainless steel heat exchanger in it.

Check this comparison between a stainless steel and aluminium heat exchanger’s lifespan below:

which boiler is best, stainless steel vs aluminium


As you can see, an aluminium heat exchanger starts off slightly better than stainless steel because of higher thermal conductivity.  But over the life of the boiler due to daily thermal stresses, and being more prone to corrosion, the drop in output and energy efficiency is massive!

This means a Viessmann boiler will be durable and reliable for much, much longer compared to boilers with an aluminium heat exchanger.  And will save your money on energy bills long after other boilers have broken down or need frequent repairs.

No other brand can use the patented Inox-Radial design.  Nor do they have the facility or the know-how to manufacture it in-house to keep the costs down.  Which is why when you go with any other brand, you’re getting a below par boiler for the same price.

See this comparison between two of the best boiler brands in the UK: Worcester Bosch vs Viessmann

2. World Leading Commercial Heating Experience

Not very well known in the UK residential boiler market, Viessmann have a long and rich history in the commercial heating space.

Many of the world’s largest stadiums, corporate buildings, and factories depend on Viessmann for their central heating.  This includes the Principality Stadium and Wales Millenium Centre in Cardiff, Wales, UK.

Interesting anecdote time; the Vaillant manufacturing facility in Germany is kept warm by a Viessmann commercial boiler, because Vaillant couldn’t build one or find one big enough!

3. Most Impressive Boiler Range in the World

Solution for Every Need.

No other boiler brand in the UK can boast of sky high 98% efficiency on residential boilers like the Vitodens 200-W or the Fuel Cell Heating Appliance, the Vitovalor 300-P (generates power and heat simultaneously).  And as we discussed earlier, floor standing, space saving storage combi boilers like the Vitodens 222-F and the Vitodens 242-F.

which boiler is best 2019, viessmann boiler range

4. Focus on Energy Efficiency and Excellence

Viessmann’s focus remains on making highest efficiency, technologically brilliant boilers.  That’s helped them win the Which? Best Buy Boiler UK status for the second year running in 2018.

Which boiler is best 2019, viessmann which best buy 2018

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