Types of Boilers: Which type of boiler is best?

types of boilers

Different types of boilers available for UK homes

Choosing the right type of boiler for your home is paramount to a warm and cosy home all year round.

types of boilers

When choosing the type of boilers for your home, it’s important to understand all of the boiler options available to you before making a final decision and purchase.

With so many types of boiler systems, you need to understand what each one can bring to the table in terms of its pros and cons and that’s how you’ll find the best type of boiler that’s able to serve your home and your family adequately for many years to come.

Different types of boilers offer different benefits, and these should be taken into account when weighing up your options and deciding which types of central heating boilers suit your home best. Many people think combi boilers are the best, but it is totally home dependent, Read our quick guide now.

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What type of boiler do I have?

You may be unsure about what type of boiler you have or how it works, but here is a quick guide for you to be able to tell quickly which type of boiler you have in your home.

Combi boilerA one-unit boiler living in your kitchen cupboard.
System boilerA boiler living in a kitchen cupboard and a hot water cylinder in your airing cupboard.
Conventional boilerA boiler in a kitchen cupboard, hot water tank in the airing cupboard and a cold water tank in the loft.
Biomass boilerA one-unit system living outside.
Oil boilerDepends on whether it is a system, combi or regular boiler.
Condensing boilerDepends on whether it is a system, combi or regular boiler.

All the main different boilers that are available

There are many different types of boilers in each section. Each section has then a subsection of boilers under that bracket. Boilers can be of a different type due to the fuel they use, or how they heat, store or send water to your central heating system and hot water tap.

Natural gas boilers are the most common boiler in the UK, with the combi boiler being the most popular gas boiler due to its compact size and ease of installation and use. All gas boilers in the Uk are hydrogen blend ready to 20%

Types of gas boilers in the UK

1. Combi Boilers types of boilers

Combi boilers are the most common boiler types in the UK. They don’t have any extra parts as they are a 1 unit system.

Combi’s are generally the most cost-effective and efficient boilers around. They control both the hot water and the central heating, hence the “combi” name.

These boiler types are especially popular for anyone conscious about their environmental impact and looking to reduce their carbon footprint.

One of the reasons they’re so popular is because they don’t take up much storage space in the home. Often they live in a standard kitchen cupboard or can be wall-hung and are incredibly easy to install.

The downside of these central heating boiler types is they are not great with pressure. You can’t run water from more than one tap or shower at the same time.

Pros and Cons of a combi boiler:


  • Unlimited heating and hot water on demand for homes with up to 4 bedrooms.
  • Only heats the water you need at a specific time, making it cost-effective and eco- friendly.
  • No cylinder needed so will fit in a kitchen cupboard.
  • It’s easy to find what size boiler you need for your home.
  • Low new boiler cost


  • Water pressure can reduce if you run more than 1 tap at a time.
  • No backup source of hot water if the boiler breaks down.
  • Very rarely will be compatible with solar panels unless it is an electric combi boiler

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2. System Boilers types of boilers

System boilers are a closed system, usually containing two parts – a boiler and cylinder. The boiler part heats up your water which is then stored in the cylinder.

System boilers are better options for some households because they allow you to run multiple taps or showers at the same time. They’re ideal if you have multiple bathrooms with a high demand for hot water.

System boilers tend to be quite economical to run, and they are relatively compact too. This boiler type would mean the boiler would live in a kitchen cupboard and then the hot water cylinder would live in the airing cupboard.

They offer a constant supply of hot water on demand, and you won’t need to worry about low boiler pressure problems. Immersion heaters can also be placed inside the hot water tanks or have them built-in. Some hot water cylinders like the Megaflo system have them already built into the design to ensure they always have hot water and lots of it.

Pros and Cons of a system boiler:


  • Faster and more simple to install than a regular one because all components are built into one unit.
  • Saves space because no cold-water tank is needed.
  • Faster and more effective hot water to multiple taps at once.
  • Can be used with an immersion heater


  • If the cylinder is not insulated well, it may lose heat.
  • Storage will be needed for the cylinder.
  • Hot water ready on demand will depend on the size of your cylinder.

3. Conventional Boilers types of boilers

Conventional boilers are the oldest type of boilers on this list, and that’s why they’re also known as traditional or regular boilers.

They use both a hot water cylinder in the airing cupboard and a cold water storage tank in the loft. This means they can take up quite a lot of space in the home.

If you have that space available, you shouldn’t necessarily rule out this option because it does offer some benefits that other types of boilers can’t offer as well.

Conventional boilers are very good at supplying water to different parts of the home at the same time, which is something that combi boilers really struggle with.

Conventional boilers are also by far the best option for homes that already have problems with low water pressure.

They are also compatible with a wide range of energy-efficient options such as solar thermal systems.

However, water has to be heated, so it’s not available on demand.

Pros and cons of a conventional boiler:


  • Hot water can run from more than one tap at a time.
  • Heat only boilers can work even if boiler pressure is low.
  • Compatible with solar panels.
  • If you already have this system, a few pipework changes could be possible for a new installation.
  • An electrical immersion heater can be installed in the cylinder, so if your boiler breaks down; you still have hot water back up plan.


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4. Oil Boilers types of boiler

Oil boilers are best suited to homes that don’t have any connection to the mains gas supply. The oil is heated up which in turn heats up the water for your home.

They’re typically suited to homes that don’t have any connection to the mains gas supply.

They tend to be used in quite isolated and rural areas, and as a result, they tend to be more expensive to run.

The main thing that makes this type of boiler different is the fact that they use oil to run rather than gas.

Oil boiler types

Oil boilers can also be combi boilers, system boilers, or conventional boilers, just like gas. This means that they work exactly the same as each of these models, but the only difference is that they burn oil instead of gas.

Pros and Cons of an oil boiler:


  • Stops any heat escaping so always has a better throughout and increases efficiency.
  • Can be fitted internal or external
  • Most efficient if gas isn’t available.
  • Commissioning at the installation increases the overall life and requires less maintenance.


  • Oil prices fluctuate.
  • Oil boiler requires a tank underground.
  • You need to buy and store oil that is required for heating.
  • If war breaks out, the oil will be cut off.

5. Biomass Boilers types of boiler

Biomass boilers, also known as wood boilers, run using logs or wood pellets.

These biomass boilers generate heat in a cheap and affordable way. If you care about saving money, a biomass boiler may be the place to look.

They tend to be very energy efficient as well; they’re among the most sustainable options out there at the moment and an alternative to gas boilers.

Pellets tend to help these boilers run better, but logs are cheaper to buy.

Biomass boilers pros and cons:


  • Wood pellet fuel supply is unlikely to see a price hike.
  • They are carbon neutral, ideal for reducing carbon tax.
  • Perfect off-grid solution.
  • Renewable heat incentive payments are likely to cover the costs of your investment so that you will get it all back in the long run.


  • More expensive than gas boilers to fit.
  • Space for fuel storage is needed outside of your home.
  • Access for the fuel delivery lorry is needed.
  • Annual servicing is required.

6. Gas Condensing Boilers types of boiler

The first thing you need to know about condensing boilers is that they’re not a category of new boiler like the others on the list.

Different types of boilers in the UK such as combi boilers, system boilers, and regular boilers can all be condensing boilers.

Simply, condensing boilers are green and designed for energy efficiency. They trap wasted, latent heat that tries to escape through the flue and uses this to heat your home. With other types of boiler such as non-condensing boilers, this latent heat is lost. 

All new gas boilers in the UK are condensing gas boilers by law. Since the introduction of this technology which makes them over 90% energy efficient, it was brought into legislation that all new gas boilers manufactured and sold in the UK had to be condensing.

Check out the best gas combi boilers right now which all have this condensing technology built-in. for maximum efficiency

Condensing boilers pros and cons


  • Condensing boilers are the best types of boilers for the environment. 
  • Condensing boilers allow you to heat your home in a way that’s much more efficient, and that means you’ll save money on your heating bills and save energy as well.
  • All types of gas boilers and oil boilers have to be condensing when new and replacements.


  • Condensing boilers can be more expensive.
  • Can be costly to maintain.

Which are the best types of boilers?

Choosing the best boiler type that’s right for you can be tricky, but knowing about all of the options above is the important first step.

From there, you should think about the size of your home, if you need a lot of hot water on demand, heat-only boiler, your energy setup if it will run off oil, electric or gas boiler, and how much available space you have.

There is a lot of rated boilers on the market with a range of different boilers to suit different peoples needs.

types of boiler

Best boiler types for central heating

The best boiler types for central heating are gas boilers. The size of your central heating system will decide how powerful your boiler is, whereas, your hot water demand will also make a difference, if you have multiple bathrooms and showers, then system or conventional types are best.

The type of boiler you have will also affect your central heating cost per hour, so choosing the right one for you whilst also keeping the financial aspect in mind is important.

The top brands for all these boiler types are Viessmann, Worcester Bosch, Baxi, Vokera, Glow Worm and Ideal.

Can I change from one boiler type to another?

Yes, changing the boiler type is called converting a boiler. Converting a boiler can benefit your home if your heating or hot water demands have changed, or you have a really old conventional boiler and a new combi boiler could easily do the same job in a much more energy-efficient way

A lot of companies offer a new boiler including home and boiler cover which keeps your warranty validated, and is included in the cost of the boiler.

Talk to an expert if you would like further guidance on a domestic boiler, or to get a great boiler deal take our quick online fixed price calculator now. We have some great cheap boilers ready to go for every home. 

At Boiler Central we also offer various boiler finance options


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