Pros and Cons of Different Boiler Types

Whether you’re a homeowner looking for a replacement boiler or you’re simply interested in finding one that’s more efficient, figuring out which boiler type is right for you can take a lot of effort.

The majority of people don’t tend to think about boilers until they have to, so the amount of information out there can get a little overwhelming or confusing when you do find yourself diving down the boiler rabbit hole.

If you’re interested in a more in-depth look at boiler types and how they work, check out Boiler Types Explained: The Ultimate Guide. For now, let’s make finding the boiler for you a bit simpler.

We’re going to take a look at the pros and cons of combi boilers, conventional boilers and system boilers, the three most common boiler types used in UK households. This should help you decide which option fits your needs best.

First, we need to understand what it is you actually need. It’s important that you keep these four questions in mind when you’re considering which boiler is right for you:

-          How many people live in your house?

-          How many bathrooms do you have?

-          How much free space do you have?

-          How much hot water do you need?

As important as central heating is (especially in the winter), when you’re considering boiler types bear in mind that it’s hot water that will play the key part in your decision-making.

Now, let’s get to the advantages and disadvantages of different boiler types!

Pros and Cons of Combi Boilers

What is a combi boiler?

combi or combination boiler is an all-in-one boiler unit that’s currently the most common boiler type in the UK.

Pros and Cons of Combi Boilers


They provide instant hot water. Combi boilers heat the water you need when you need it, so you don’t have to worry about running out of water and then having to wait a while for more water to be heated.

They require less space. The great thing about combi boilers is that your hot water and central heating are managed in a single, all-in-one unit. Almost all the system components are housed within the boiler itself, so there’s no need for large water tanks in the loft or a hot water cylinder in your airing cupboard. That means they’re great for smaller houses or homes where space is at a premium.

They’re energy efficient. A combi boiler’s efficiency comes from the way that water is heated. When you turn on a tap, water flows directly from the mains, is quickly heated by heat exchangers in the boiler and then passes into your tap. That means combi boilers only heat the water you need, exactly when it’s needed and there’s no energy wasted on heating large hot water cylinders.


Hot water pressure can be restricted. Combi boilers heat water on demand so if you have a larger house and multiple people need hot water at the same time (maybe you’re running a bath while your partner’s doing the dishes) then you’ll run into some trouble. Combi boilers are ideal for smaller houses as hot water pressure is reduced when there’s a higher demand for hot water.

They depend on your area’s mains water pressure. If water pressure in your local area is very low, then a combi boiler may not be suitable for you. It’s worth having an engineer take a look at the water pressure in your area before making a decision on which boiler you should choose.

Boiler breakdown means no heating or hot water. If the worst should happen and your combi boiler breaks down, you will be left with no central heating and no hot water. This is because both systems are managed in one unit and there’s no backup heater, such as an immersion heater.

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Pros and Cons of Conventional Boilers

What is a conventional boiler?

conventional boiler is the most traditional boiler system in the UK, though it’s fallen in popularity in favour of the combi boiler recently. This system is made up of a boiler unit, a hot water cylinder, a cold water tank, and a feed and expansion tank (the tanks will need to be up in the loft).

Pros and Cons of Conventional Boilers


If your boiler breaks down then you’ll still have hot water. Conventional boilers store and heat water in a hot water cylinder. If the worst should happen and your boiler breaks down, then your immersion heater will allow you to heat water using electricity instead of your boiler, so you’ll still have access to hot water.

They suit low-pressure areas. Conventional boilers are ideal for areas where the local water pressure is low because the water comes from the water tanks in your loft and moves down into your system to the floors below, creating pressure that’s gravity-fed. This also means that conventional boilers are more compatible with older heating systems that can’t handle mains water pressure.

They can be cost-effective. If you have an older heating system or an existing conventional boiler that needs to be replaced, then it can be more cost-effective to replace them with another conventional boiler. This type of boiler is also quite easy to maintain.


They can’t provide hot water on demand. Once your hot water cylinder has run out of water, you’ll have to wait for it to fill up again. You might even find that you have no hot water for a little while after you’ve run a bath.

They’re less efficient than combi boilers. In a combi boiler, water is heated on demand so it only heats what’s necessary, but in a conventional boiler water is heated in advance and then stored in your hot water cylinder. The water that’s been stored will then gradually lose heat over time, making a conventional boiler system less efficient.

They take up a lot of space. Conventional boiler systems have water tanks and a water cylinder that need to fit somewhere into your house, so if you have a house with limited room or no loft space, then this system won’t suit you.


Pros and Cons of System Boilers

What is a system boiler?

system boiler is quite like a conventional boiler however it takes cold water directly from the mains instead of using water tanks. A system boiler consists of a boiler unit and a hot water cylinder that’s usually hidden away in an airing cupboard.

Pros and Cons of System Boilers


They provide mains pressure hot water to your taps.  System boilers take water from the mains and heat it in a hot water cylinder, so they’re able to provide a supply of hot water to several taps at once at mains pressure. This means that system boilers are ideal for larger families and homes with more than one bathroom.

They’re more compact than conventional boilers. System boilers don’t require bulky water tanks in the loft, so they’re ideal if you were thinking of doing a loft conversion. You also don’t have to worry about loft pipes freezing with a system boiler.

They’re compatible with solar energy sources. While the way that water is heated may not be as efficient as it is in combi boilers, the way system boilers are powered can be superefficient. The hot water cylinder can be compatible with solar water energy should you want to lower your carbon footprint (as well as energy costs).


They’re not as efficient as combi boilers. Like conventional boilers, system boilers heat water and store it in a hot water cylinder where they will slowly lose heat.

Hot water can run out. Once the hot water has run out, you’ll have to wait for the hot water cylinder to heat more water before you can use it again. If you’re not great at remembering to turn the hot water on in advance, or forget to set a timer, then you might be in for a few cold showers with this boiler system.

They take up living space. While system boilers don’t require bulky tanks in your loft, you do still need to find space for your hot water cylinder. These usually fit into an airing cupboard, but they’re probably not ideal for homeowners who are short on space.

 As you can tell, there are advantages and disadvantages to each boiler type. If you’re a homeowner trying to figure out which boiler to get, it isn’t about choosing the best boiler but choosing the right boiler to suit your needs. So, go back to the questions asked at the beginning and think about which boiler is right for you.

And when you’ve made your decision, it’d be very easy to push thoughts of your boiler to the back of your mind again, but don’t forget about it just yet.

Boiler breakdowns can happen for any number of reasons and you don’t want to be left paying an arm and a leg because you didn’t have any boiler cover. YourRepair’s boiler and home care plans can give homeowners and landlords the peace of mind that your boiler is in safe hands.

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