What type of boiler do I have?


How can I identify what type of boiler I have?

When identifying a boiler you must consider a few things. Whether you have a tank and cylinder are two defining characteristics to get you started. The rest will be covered step-by-step below.

3 Types of Boiler Explained: Combi, System & Regular boilers

Combi Boilers – This is the most widely used boiler in UK. Combi boilers provide the heat for the hot water and central heating in your home. This type of heating only provides heat and hot water when needed and runs straight from the mains water (No water tanks needed here).

System Boilers - With a system boiler you will not have a large cold water storage tank taking up valuable space in your attic. This type of boiler stores hot water in a storage cylinder, normally within an airing cupboard.

Regular Boilers - Regular boilers have a hot water cylinder usually in an airing cupboard, while the cold water tank located in the attic. They are ideal for homes that need lots of hot water on demand. Regular boilers are sometimes called traditional or conventional boilers.

What type of fuel does your boiler use?

There are several types of fuel available that can be used. In most cases it will be either:

  • Natural Gas - Supplied directly from the Gas main.
  • LPG - You would usually have a LPG storage tank in your garden.
  • Oil

What is a Standard boiler?

Identifying features: You should see two pipes coming out of the top and one coming out of the bottom. It will also have a hot water cylinder and a cold water storage tank, this will usually be located in the loft.

What homes are they most suited to?

You’ll most commonly find standard boilers in large properties.

Expansion vessel

An Expansion tank is used to relieve pressure within your pipe work. If the tank fails to do this it will release pressure through its valve.

Header tank

  • Feeds water into the central heating system when the water is low.
  • Provides a place for hot water to go if your system has overheated.


The pump pushes hot water around your heating system. The pump prevents the water from just sitting in the pipes. You’ll be able to find this inside your boiler or in your airing cupboard.

What is a Combi Boiler?

Identifying features: You should see some Copper pipes beneath your boiler, there will usually be five of these. You’ll also have no external pump or large clunky hot water cylinder.

What homes are they most suited to: You would generally choose this boiler if you live in a flat or a small-medium house with only one bathroom.

Benefits: Instant and unlimited hot water and heating. No large tanks required, which creates more space within your home.

Drawbacks: If you need to use more than one output e.g. run taps and run a shower at the same time, you may struggle with water flow.

What is a System boiler?

Identifying features: The easiest way to identify a system boiler is to check if you have a hot water storage cylinder in an airing cupboard, followed by making sure you don't have a cold water tank in the attic. If you boiler has a hot water cylinder but no cold water tank, it will be a system boiler.

What types of homes are they most suited to: Bigger homes and large properties that require hot water from multiple outlets at once e.g. taps, running your bath or shower at the same time.

Benefits: There is no huge tank in your loft, just the water cylinder which is usually tucked away in the airing cupboard.

Drawbacks: Unlike a combi, a system boiler won’t give you instant hot water on demand. What it does hold is limited by the size of the cylinder. When this runs out you will need to wait for more hot water to be heated.

Other boiler types: How do you identify them?

Do I have a back boiler?

The back boiler is an boiler that gained popularity in the 60's and 70's. They are located in the fireplace and use the chimney to flue their gases out of the property.

You can usually tell if you have a back boiler by looking at your gas fire. If you take off the plate at the bottom of the heater, there will be a model number under there that you can check. You should be able to see the pilot light as well.

Which type of boiler do I need?

You need to find a boiler that is not too small that it won't be able to heat your home properly or produce enough hot water. A boiler that is too big will use more fuel, making your energy bills more expensive.

By using the above information you can now identify your current boiler correctly and be assured you can now make the right choice. To find a boiler tailored to the size of your home try going through our online process: