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No matter what type of fuel your boiler runs on, there are different types of boiler available. 

A combination (combi) boiler is the most common type of boiler the UK. But it's not the best option for everyone. 

Heat-only and system boilers are better suited for a variety of situations, and the wrong type could lead to significantly higher bills or long delays for hot water.

Read on to learn more about the various types of boiler and to find out the pros and cons of each, plus how a condensing boiler could save you hundreds on your heating bills. 

Half of homeowners, on average, consider changing brand when getting a new boiler installed (Which? boiler survey 2021). Read our best gas and oil boiler brands guide to discover the ones to go for.

Every home is different, and so the right type for your household may be different to your neighbour's. Read on to discover more pros and cons for the various types of boiler. 

Combination boilers connect directly to the mains cold water supply, providing hot water on demand. They are a great choice for many homes, especially for smaller houses and flats that only have one bathroom, as they have a lower hot water and heating demand than larger properties.

Decided a combi boiler is for you? Find out what the best combi boilers brands are, or go straight to our  expert reviews of combi boilers

Also known as 'conventional' or 'regular' boilers, heat-only boilers provide heat directly to your radiators and connect to a water tank to provide hot water. You will also normally have an on/off switch - so you can heat water in the storage tank when you know you're going to need it, and leave it switched off when not in use. 

An 'open-vented' heat-only system - the most common heat-only boiler system - requires a cold water feed and expansion tanks in the loft.

Heat-only boilers typically have components housed externally from the boiler, such as a circulation pump.

Good for larger households - if you have multiple bathrooms with people frequently needing to use hot water at the same time, a heat-only boiler will meet this demand.

Have you decided that a heat-only boiler is the type for you? Take a look at our best heat-only boiler reviews .

Sometimes known as 'closed vent' or 'sealed system' boilers, system boilers require a hot water cylinder. However, unlike conventional boilers, they don't require a cold water tank, and components that are external in a conventional boiler, such as pumps and valves, are built into the body of a system boiler.

A system boiler is the perfect choice if you think you'll need a heat-only boiler but don't want lots of external components.

Have you decided a system boiler is for you? Head straight to our best system boiler reviews . 

A less common system,  storage combi boilers work like a combination boiler, but have an internal hot water cylinder built into the boiler.

They are a good solution if you have a higher hot water demand but don't have the space for the separate hot water cylinder that a system or heat-only boiler requires. 

Pros of storage combi boilers

Cons of storage combi boilers

 Decided that having a storage combi boiler is right for you? Read our best storage combi boiler reviews .

Condensing boilers are more efficient and 'greener' than older non-condensing boilers. They make the fuel you burn go further, meaning you'll produce fewer carbon emissions while reducing your heating bills. 

Replacing an old, less efficient, non-condensing boiler with a new, high-efficiency, condensing boiler could save you between £45 and £300 a year on your heating bill (Energy Saving Trust, 2021).

All types of boiler can be condensing boilers. Since 2007, except in exceptional circumstances, building regulations have stated that all new boilers installed in a domestic home should be high-efficiency condensing boilers.

So the chances are you already have one if you've had a new boiler installed since 2007.

With a non-condensing heat-only boiler, some heat is wasted in the form of hot gases released from the flue. 

A condensing boiler captures some of the heat from these gases and uses it to heat water returning from your central heating system. It therefore requires less heat from the burner and is more efficient.

All new modern boilers are condensing boilers. So if you're thinking of replacing an old boiler with a new one, you will be buying a new condensing boiler and gaining all of the efficiency savings that come with it.

Getting a Gas Safe qualified heating engineer to install a new boiler will ensure it operates efficiently. Find a Which? Trusted Trader or use our Trusted Traders search tool below to find a local trader in your area

Stoves can be connected to a regular boiler, such as a gas boiler, or a biomass boiler. Biomass boilers, like stoves, burn wood to generate heat. They can be used along with a stove, or on their own, and are particularly good for homes not connected to mains gas.

You can also get a 'wet' stove, where an integral biomass boiler is built into the firebox. This should make the most of the heat. In some cases, you can get these retrofitted to the stove using a 'clip'.

There are also pellet boiler stoves, another form of stove and boiler in one, and flue boilers, which fit onto the flue connection between the stove and the chimney.

We wouldn't recommend adding a 'back boiler' to an old open fire as these are a lot less efficient and more polluting than modern stoves.

You can use a thermal tank to link up a range of other heating systems too, such as solar panels   and a gas boiler with a wood-burning stove. 

A thermal tank (also known as a buffer tank or accumulator) will help regulate the fluctuating use of the different energy sources - eg sun for solar panels in the summer and logs for a wood-burning stove in the winter.

If you’re thinking about replacing your boiler, use our research to buy one you can rely on. See our boiler reviews . You can also use our wood-burning stove reviews   to find out which companies have boiler stove options.

We will all be making the transition to low carbon heating over the next few decades. A gas boiler may be the best option for you currently, but these produce carbon emissions and will eventually be phased out. If you want to consider a lower carbon heating option now, read our expert guides on: