heating & energy

Best Boiler

https://www.housetastic.co.uk/authors/profile-images/kim.jpg
Kim
21st April, 2022 | 20 minute read

Are you on the search for the best boiler on the market? If so, we're here to help!

We have created this guide with everything you need to know about boilers, including the different types, how a boiler works, and what to consider before buying a new boiler.

woman turning up boiler

We have also created a list of the best boilers on the market to help you in your search for a new boiler. We have researched the best boiler brands to provide you with the best of the best.

What Is a Boiler?

A boiler is a unit that makes up the most important part of a central heating system. This unit is what produces the heat needed for the central heating system to work.

It is essentially a small furnace powered by gas, LPG, or oil. Most boilers in the UK are fuelled by natural gas that automatically feeds into it from the national gas grid.

There are several different types of boilers, and each one operates a little differently. We will go into detail about the different types of boilers later in this article.

How Does a Boiler Work?

In most typical gas central heating boilers, there are pipes that enter the boiler from underneath.

One of these pipes feeds gas into the boiler from the mains gas supply, while one pipe lets water enter the boiler so that it can be heated up from there, and another pipe allows hot water to exit the boiler so that it can be pumped around the central heating system.

inside of a boiler

During operation, a valve that is connected to the boiler opens up and allows gas to enter a sealed combustion chamber, an electric ignition system, or a permanent pilot and then it ignites to burn the fuel.

Hot jets attached to a heat exchanger inside the boiler transfer the heat to the water which flows over the exchanger. An electric pump then pushes the heated water through your system to your radiators and taps.

Types of Boiler

There are several different types of boilers, and the right one for you can depend on your particular home and heating system.

To help you figure out which boiler might be best for you, we have created this list of the different types of boilers and the advantages and disadvantages of each type.

Condensing Boilers

All combi, system, or conventional boilers that are installed in the UK must be condensing by law. This is a type of property that all boiler units must now possess. Condensing boilers have larger heat exchangers and use the latent heat as fuel.

Ordinarily, this heat would escape into the atmosphere. So with this in mind, new condensing boilers are much better for the environment than many traditional systems.

Combi Boilers

Combi boilers are usually the most cost-effective type of boiler to have in the home. These boilers control both hot water and central heating. They are very energy efficient, and that is why they are a very popular choice for many homeowners in the UK.

combi boiler

Combi boilers heat water from the mains whenever a hot tap is turned on, meaning you have an unlimited supply of hot water whenever you need it. There is no bulky cylinder or water tank needed for this type of boiler.

System Boilers

If you live in a large home or one with multiple bathrooms, then a system boiler may be the best option for you. These boilers do require a cylinder for hot water but don't need a water tank.

The pump and expansion vessel are both built into the system, so no tank is needed. This makes them easier to maintain, and homeowners can worry less about frost damage or leaks.

Conventional Boilers

Conventional boilers are also known as traditional boilers, open vent boilers, or heat only boilers. These boilers need both a cylinder and a water storage tank. While these aren't great space-savers, they can supply large volumes of hot water to multiple bathrooms, so they're great for larger homes.

conventional boiler

These boilers tend to be best for homes where a traditional system is already in place so that any pipework changes are minimal. These boilers can also be used with solar heating systems to reduce your energy bills and make them much better for the environment.

Best Boiler

Now that you know the difference between the most popular boiler styles in the UK, it's time to take a look at the very best boilers available on the market.

Here, we have rounded up the best of the best to help you make the right choice when it comes to purchasing a new boiler.

Best Oil Boiler

Worcester Bosch Greenstar Heatslave II

 Worcester Bosch Greenstar Heatslave II

This particular boiler is a condensing combi boiler that can be installed externally. This means that it won't take up any room at all around the home. Since it is a combi boiler, it can provide hot water and central heating on demand and has an impressive flow rate of 15 litres per minute.

This boiler is available with several output ratings, including 18kW, 25kW and 32kW. This makes it much easier for you to find the right boiler for your home. It is energy-efficient and compact, so overall a great choice for modern homes.

Things we liked
  • It can be installed externally
  • Provides instant hot water
  • Various power outputs
  • Energy efficient
  • Compact design
  • 5-year warranty
Things we didn't like
  • Quite expensive
  • Requires oil fuel

Grant VortexBlue

 Grant VortexBlue

The Grant VortexBlue boiler is a combi boiler that runs on oil. Since it is a combi boiler, it can provide hot water and central heating on demand without the need for any external cylinders.

It can be purchased in a range of outputs, including 21kW, 26kW, and 36kW, so you can easily find a suitably powerful boiler for your particular home. As standard, this boiler comes with a 2-year warranty for peace of mind.

Things we liked
  • Provides instant hot water
  • It can be purchased in a range of outputs
  • 2-year warranty
  • Energy efficient
  • Compact design
Things we didn't like
  • Quite expensive
  • Requires oil fuel

Best Gas Boiler

Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

 Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

This amazing boiler has a 35kW output that is powerful enough to fulfil all of your heating needs. It is a compact design that won't take up too much room in your home, and since it's a combi boiler, it can provide instant hot water and central heating.

It is an AA rated product that comes at a reasonable price and provides you with everything you need from a gas boiler. As a bonus, this machine also comes with a three-year warranty.

Things we liked
  • Powerful boiler
  • Reasonable price
  • 3-year warranty
  • Compact design
  • Instant hot water
Things we didn't like
  • N/A

Vaillant ecoTEC plus Combi

 Vaillant ecoTEC plus Combi

This particular boiler is Vaillant's most popular model and is widely recommended by professionals. It comes in various outputs, including 25kW, 32kW, 35kW and 38kW.

This means that you can easily find the right kind of powerful boiler to suit the needs and size of your home.

It is a very stylish model with a backlit display, coloured case, and a stainless steel heat exchanger. It runs very quietly and also has the benefit of coming with a five-year warranty as standard.

Things we liked
  • Recommended by professionals
  • Various outputs
  • Stylish design
  • Runs very quietly
  • Provides instant hot water
  • 5-year guarantee
Things we didn't like
  • N/A

Worcester Bosch Greenstar i Combi

 Worcester Bosch Greenstar i Combi

This particular model is the most popular of all Worcester Bosch boilers. It has been awarded the Which? Best Buy Award for seven years in a row and regularly tops the polls in both reliability and performance.

It features simple controls with a clear information display and comes in a compact design easily installed in kitchen cupboards. It is very efficient and powerful, however, it is most suited to small and medium homes.

Things we liked
  • Popular model
  • Which? Best Buy Award for seven years running
  • Simple controls
  • Compact design
  • Powerful
  • Energy efficient
Things we didn't like
  • Not the best model for larger homes

Best Electric Boiler

Comet Combi Boiler by Electric Heating Company

 Comet Combi Boiler by Electric Heating Company

The Comet Combi boiler features a 140-litre Duplex stainless steel hot water cylinder to provide plenty of hot water for your home. Despite the large cylinder, it is very compact and is pre-plumbed and pre-wired, making it very easy to install.

It features a built-in programmer that allows you to set the schedule and temperature for your heating and also features a wireless thermostat.

It comes in a variety of outputs, including 9kW, 12kW and 14.4kW. You have the option of setting the heating only or the hot water only, or you can combine both. The boiler includes a 2-year warranty, and the cylinder has a 10-year warranty.

Things we liked
  • Large capacity
  • Compact size
  • Easy to install
  • Various outputs
  • Various controls
  • Long warranties
Things we didn't like
  • It may be expensive to run

Electromax by Heatrae Sadia

 Electromax by Heatrae Sadia

The Electromax boiler can provide hot water and heating to your home at the same time as it combines a hot water storage cylinder with an electric flow boiler and a circulating pump. All this system needs to run is a cold water supply and electricity supply.

Inside this boiler is a 180-litre duplex stainless steel unvented cylinder that allows it to power a mains pressure shower and can also fill up a bath fast.

This boiler is designed for sealed systems and is small enough to fit in a standard airing cupboard. It comes in two output sizes – 6kW or 9kW. This system benefits from a two-year warranty on the boiler and a ten-year warranty on the cylinder.

Things we liked
  • Powerful water supply
  • Large capacity
  • Compact design
  • Various outputs
  • Long warranties
Things we didn't like
  • It may be expensive to run

Best Condensing Boiler

Worcester Bosch Greenstar i Combi

 Worcester Bosch Greenstar i Combi

This particular model is the most popular of all Worcester Bosch boilers. It has been awarded the Which? Best Buy Award for seven years in a row and regularly tops the polls in both reliability and performance.

It features very simple controls with a clear information display and comes in a compact design that can easily be installed in kitchen cupboards. It is very efficient and powerful, however, it is mostly suited to small and medium homes.

Things we liked
  • Popular model
  • Which? Best Buy Award for seven years running
  • Simple controls
  • Compact design
  • Powerful
  • Energy efficient
Things we didn't like
  • Not the best model for larger homes

Vitodens 050-W Condenser Boiler

 Vitodens 050-W Condenser Boiler

This compact, low-cost condensing boiler is the perfect option for modern homes. It is very highly efficient to help you save on your energy bills and has low CO2 emissions for a reduced environmental impact. The machine can easily be operated and features an LCD screen for even further ease of use.

It even comes with smart features and can be linked to an app on your phone, so you can control your boiler from wherever you are. It is rated class A for energy efficiency and benefits from an extended warranty of up to 10 years.

Things we liked
  • Compact design
  • Highly efficient
  • Low CO2 emissions
  • Easy to operate
  • Smart features
  • Extended 10-year warranty
Things we didn't like
  • Not as powerful as some other boiler models

Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

 Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

This amazing boiler has a 35kW output that is powerful enough to fulfil all of your heating needs. It is a compact design that won't take up too much room in your home, and since it's a combi boiler, it can provide instant hot water and central heating.

It is an AA rated product that comes at a reasonable price and provides you with everything you need from a gas boiler. As a bonus, this machine also comes with a three-year warranty.

Things we liked
  • Powerful boiler
  • Reasonable price
  • 3-year warranty
  • Compact design
  • Instant hot water
Things we didn't like
  • N/A

Best System Boiler

Veissman Vitodens 100-W Boiler

 Veissman Vitodens 100-W Boiler

This particular boiler is a wall-mounted gas condensing system boiler that is a great choice for those looking for a high-quality boiler at a good price.

It comes in a range of sizes, including 26kW, 30kW, and 35kW. This boiler is the perfect choice for people with a large home who require hot water to come out of multiple taps at once.

It is efficient and reliable and comes with an LCD touchscreen for ease of use. It also comes with the benefit of a 5-year standard warranty.

Things we liked
  • Reasonable price
  • Range of outputs
  • Great for large homes
  • Efficient
  • LCD touchscreen controls
  • 5-year warranty
Things we didn't like
  • N/A

Worcester Bosch Greenstar i System

 Worcester Bosch Greenstar i System

The Worcester Bosch Greenstar i system is a highly efficient A-rated boiler. This boiler does require a hot water cylinder, however, it doesn't need a feed and expansion cistern. This makes it a quick and easy boiler to install, and it is also very efficient and economical to run.

With this model, heat from the exhaust gases is recycled to save energy and reduce your carbon footprint. This system also comes with the benefit of a 5-year standard warranty.

Things we liked
  • Highly efficient
  • Quick to install
  • Economical
  • Recycled gases to reduce carbon footprint and reduce bills
Things we didn't like
  • Requires cylinder

Vailliant ecoTEC plus Combi

 Vailliant ecoTEC plus Combi

This particular boiler is a very popular model and is widely recommended by professionals. It comes in various outputs, including 25kW, 32kW, 35kW and 38kW. This means that you can easily find the right kind of powerful boiler to suit the needs and size of your home.

It is a very stylish model with a backlit display, coloured case, and a stainless steel heat exchanger. It runs very quietly and also has the benefit of coming with a five-year warranty as standard.

Things we liked
  • Recommended by professionals
  • Various outputs
  • Stylish design
  • Runs very quietly
  • Provides instant hot water
  • 5-year guarantee
Things we didn't like
  • Higher price than most other system boilers

Best Internal Boiler

Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

 Viessmann Vitodens 200-W 32/35kW Natural Gas Combination Boiler

This amazing boiler has a 35kW output that is powerful enough to fulfil all of your heating needs. It is an AA-rated boiler machine that comes at a reasonable price and provides you with everything you need from a gas boiler.

As a bonus, this machine also comes with a three-year warranty for peace of mind. It is a compact design that won't take up too much room in your home, and since it's a combi boiler, it can provide instant hot water and central heating.

Things we liked
  • Powerful boiler
  • Reasonable price
  • 3-year warranty
  • Compact design
  • Instant hot water
Things we didn't like
  • N/A

Worcester Bosch Greenstar i Combi

 Worcester Bosch Greenstar i Combi

The Worcester Bosch Greenstar i Combi boiler is the most popular of all Worcester Bosch boilers. It has been awarded the Which? Best Buy Award for seven years in a row and regularly tops the polls in both reliability and performance.

It features simple controls with a clear information display and comes in a compact design that can easily be installed in kitchen cupboards. It is very efficient and powerful, however, it is most suited to small and medium homes.

Things we liked
  • Popular model
  • Which? Best Buy Award for seven years running
  • Simple controls
  • Compact design
  • Powerful
  • Energy efficient
Things we didn't like
  • Not the best model for larger homes

Best External Boiler

Firebird Enviromax Blue Supreme Slimline Heatpac 26kW External Regular Oil Boiler

 Firebird Enviromax Blue Supreme Slimline Heatpac 26kW External Regular Oil Boiler

The Firebird Enviromax Blue Supreme is a great condensing oil boiler that is ideal for installation outside in a dedicated boiler house, in a garage or an outbuilding.

It is A-rated on efficiency and is built from premium-grade steel. It is available in two outputs – 20kW and 26kW so you can easily find a suitable one for your home.

It features the latest blue flame technology and benefits from coming with a five-year warranty for your peace of mind.

Things we liked
  • Perfect for external installation
  • A-rated energy efficiency
  • Latest blue flame technology
  • 5-year warranty
Things we didn't like
  • Quite expensive
  • It may be difficult to install

Grant VortexBlue

 Grant VortexBlue

The Grant VortexBlue boiler is another powerful boiler that can also be installed externally. This combi boiler runs on oil. Since it is a combi boiler, it can provide hot water and central heating on demand without the need for any external cylinders.

It can be purchased in various outputs, including 21kW, 26kW, and 36kW, so you can easily find a suitably powerful boiler for your particular home. As standard, this boiler comes with a 2-year warranty for peace of mind.

Things we liked
  • Provides instant hot water
  • It can be purchased in a range of outputs
  • 2-year warranty
  • Energy efficient
  • Compact design
  • It can be installed externally
Things we didn't like
  • Quite expensive
  • It may be difficult to install

Worcester Bosch Greenstar Heatslave II

 Worcester Bosch Greenstar Heatslave II

This particular boiler is a condensing combi boiler that can be installed externally. This means that it won't take up any room at all around the home. Since it is a combi boiler, it can provide hot water and central heating on demand and has an impressive flow rate of 15 litres per minute.

This boiler is offered with various output ratings, including 18kW, 25kW and 32kW. This makes it much easier for you to find the right boiler for your home. It is energy-efficient and compact, so overall a great choice for modern homes.

Things we liked
  • It can be installed externally
  • Provides instant hot water
  • Various power outputs
  • Energy efficient
  • Compact design
  • 5-year warranty
Things we didn't like
  • Quite expensive
  • Requires oil fuel

Best Reliable Boiler

Viessman Vitodens 100-W Boiler

 Viessman Vitodens 100-W Boiler

The Viessmann Vitodens 100-W boiler is a wall-mounted gas condensing system boiler that is a great choice for those looking for a high-quality boiler at a good price. It comes in a range of sizes, including 26kW, 30kW, and 35kW.

This boiler is the perfect choice for people with a large home who require hot water to come out of multiple taps at once. It is efficient and reliable and comes with an LCD touchscreen for ease of use. It also comes with the benefit of a 5-year standard warranty.

Things we liked
  • Reasonable price
  • Range of outputs
  • Great for large homes
  • Efficient
  • Reliable
  • LCD touchscreen controls
  • 5-year warranty
Things we didn't like
  • N/A

Best Efficient Boiler

Worcester Bosch Greenstar 24i Gas System Boiler

 Worcester Bosch Greenstar 24i Gas System Boiler

The Worcester Bosch Greenstar 24i system is a highly efficient A-rated boiler. This boiler does require a hot water cylinder, however, it doesn't need a feed and expansion cistern. This makes it a quick and easy boiler to install, and it is also very efficient and economical to run.

With this model, heat from the exhaust gases is recycled to save energy and reduce your carbon footprint. The efficiency rating of this model is 94%. This system also comes with the benefit of a 5-year standard warranty.

Things we liked
  • Highly efficient
  • Quick to install
  • Economical
  • Recycled gases to reduce carbon footprint and reduce bills
  • 94% energy efficiency rating
Things we didn't like
  • N/A

Best Boiler for a Small Flat

Worcester Bosch Greenstar 25i Gas Combi Boiler

 Worcester Bosch Greenstar 25i Gas Combi Boiler

The Worcester Bosch 25i combi boiler is a great choice for smaller homes. It is an energy-efficient and reliable boiler with A-rated energy efficiency. This boiler is manufactured to provide homes with effective heating without using excess fuel.

This boiler can help you to save money on your energy bills and reduce your carbon footprint. It is very compact, so it can easily fit into most cupboard spaces. It also features very easy controls and has the benefit of coming with a warranty of up to ten years.

Things we liked
  • Energy efficient
  • Lower your carbon footprint
  • Compact design
  • Easy to control
  • Up to 10-year warranty
Things we didn't like
  • Not great for larger homes

Ideal Logic+ 24kW Combination Boiler

 Ideal Logic+ 24kW Combination Boiler

This compact boiler is small enough to fit into an average kitchen cupboard. It comes with the benefit of being compatible with a range of fluing options and a wide variety of additional controls.

The installation is fast and easy thanks to the concealed connections, built-in automatic bypass and the integral filling loop. This particular model also comes with the benefit of a seven-year parts and labour warranty.

Things we liked
  • Low price
  • Compact size
  • Variety of additional controls
  • Range of fluing options
  • Easy to install
  • Seven-year parts and labour warranty
Things we didn't like
  • N/A

Best Boiler for a Large Home

Greenstar 8000 Boiler

 Greenstar 8000 Boiler

The Greenstar 8000 boiler is a top of the range boiler that is capable of heating large homes easily. It features innovative technology and smart controls.

You can even pair the boiler up with Bosch EasyControl so that you can easily control your boiler through your phone. It is a very quiet boiler that looks very stylish.

The LCD screen makes it very easy to use, and the sleek design would look great in any modern home. If you're looking for a top of the range boiler that really does it all, then this is the one for you.

Things we liked
  • Stylish design
  • Quiet operation
  • Smart controls
  • LCD screen
  • Easy to use
Things we didn't like
  • Expensive

Ideal Vogue C40 Gen2 Combination Boiler

 Ideal Vogue C40 Gen2 Combination Boiler

The Ideal Vogue C40 Gen2 combination boiler is a great choice for larger homes. It features a 3.5-inch full-colour display for easy controls and looks very stylish in modern homes.

This single piece unit is very easy to install and is compact enough not to take up too much space in your home.

It is rated A on energy efficiency and runs very quietly, so it'll never be disruptive. This model also comes with the benefit of an eight-year manufacturer's warranty.

Things we liked
  • Great for large homes
  • Coloured LCD
  • Compact design
  • Rated A on energy efficiency
  • Quiet running
  • Eight-year manufacturer's warranty
Things we didn't like
  • N/A

What to Consider Before Buying a Boiler

There are several things that you will need to consider before purchasing a new boiler. Below is a list of the things that you should think about before making your purchase:

Cost

Boilers can range in price quite drastically. With this in mind, it's a good idea to think about how much you're willing to spend on a new boiler before you decide which boiler is right for you.

You will also need to consider the fact that there will be additional costs involved with the installation of your new boiler, so you will need to factor the labour costs into your budget before placing a purchase too.

Type of Boiler

As you can see from above, there are many different types of boilers. Most of the time, it's a good idea to opt for the same kind of boiler that you have already, as this will cause the least amount of disruption and will be the most cost-effective option when it comes to the installation.

However, if you are looking at buying a different type of boiler, it may be smart to contact a local plumber or boiler specialist to discuss what may be involved with the work and whether you can get a particular type of boiler in your home.

Size of Boiler

Boilers come in a range of sizes, and this is something to keep in mind when searching for the right boiler for you. If your home is small, it would be a good idea for you to look out for a compact boiler.

Some boilers are small enough to be installed inside a kitchen cupboard. This allows you to take up as little space as possible in your home.

FAQs 

Who qualifies for a boiler grant?

To qualify for a boiler grant, you need to meet certain benefits criteria. Your home must also be on a mains gas supply, the boiler your replacing needs to be at least five years old, and you must be the homeowner. There is no funding for rented properties or council-owned properties.

If you are on pension credit or child tax credits, you automatically qualify for a grant. There are some other circumstances where you may be able to qualify for a grant, such as if you receive multiple types of benefits.

If you are unsure whether you could get a grant, it is best to speak to your local council for some advice.

How do you increase boiler pressure?

There are two main problems that could cause a pressure drop – if there is a leak or due to radiator bleeding. Take a look around your home for damp patches around pipes, radiators or the boiler itself.

If you find a leak, you should call a plumber to get this fixed. If you have bled your radiators recently, this can cause a drop in pressure. Check your manual first to ensure you're safe to fix the pressure yourself.

If you're happy to proceed, take the following steps to increase your boiler pressure:

  • Switch off your boiler and allow it to cool.
  • Double-check that both ends of the filling loop are attached.
  • Open both valves and allow cold mains water to enter the system.
  • Wait for the pressure gauge to read 1.5 bar.
  • Close both valves.
  • Switch the boiler back on.
  • Undo both ends of the filling loop and remove.

Should I turn my boiler off if my oil tank is being filled up?

Yes, it is recommended that you turn your boiler off. You should also leave it off for a short period after it has been filled – around 30 minutes is fine.

How often should I replace my boiler?

Boilers tend to last for around 10-15 years, however, many boilers can last longer if it is properly maintained. You should replace your boiler when it starts needing to be repaired often.

How often should I get my boiler serviced?

Your boiler should be serviced once a year to prolong its lifespan.

Sources

  1. https://www.boilerguide.co.uk/articles/what-is-a-boiler-and-how-does-it-work
  2. https://boilerhut.co.uk/boiler-guides/most-efficient-boilers
  3. https://www.britishgas.co.uk/home-services/boilers-and-heating/guides/boiler-pressure.html
  4. https://www.boilergrants.org.uk/eco-qualification-criteria.html
  5. https://www.worcester-bosch.co.uk/support/troubleshooting/faqs