Category - Boilers
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Will Scholfield, Engineer

20 Mar : Updated 18 Apr ● 4 min read

Do you need a water tank with a combi boiler?

If you’re looking to make the switch from your old boiler to a new combi boiler, you’ll likely want to know a bit more about combi boilers before you make the upgrade. 

How do they work? Do you need a water tank with a combi boiler? How do combi boilers store water?

What is a combi boiler?

A combi boiler or ‘combination boiler’ is a popular solution to central heating and hot water supplies in UK homes. 

Historically, a central heating and hot water system would have been powered by two or more heating sources. However, the combi boiler runs the central heating and hot water supply from one source - the boiler - thanks to its compact size, increased fuel efficiency and ability to supply hot water and heating on demand, as opposed to waiting for water to heat up.

In our intuitive guide, we’ve gone into more detail about ‘What is a combi boiler?’.

What is a water cylinder?

A water cylinder is just that - a cylinder that holds water. 

Commonly found in homes where a standard or system boiler is in use, the water cylinder comes in a variety of sizes, depending on household demand. Some water cylinders are kept in cupboards, like an airing cupboard, typically on the highest floor in the building or the loft if the system is gravity fed, or near the main bathroom or water connection.

The water cylinder’s primary function is to store water heated by the boiler until the water is required.

However, regardless of size, a water cylinder can only provide a system with hot water as long as it has been pre-heated and stored. So, your supply is finite until the system’s boiler can heat more water and refill the cylinder. 

Not an ideal situation when you want to enjoy a nice warm bath, following a family member using up all of the hot water before you!

We’ve discussed system boilers in a bit more depth in this article - find out ‘What is a System Boiler?’ with help from this handy guide. 

How does a combi boiler store water?

The combi boiler is designed to be compact but efficient at supplying a home with its heating and hot water demand. Therefore, combi boilers don’t require water tanks.

A combi boiler draws water directly from the water mains into the boiler, where it is heated as and when required at that point in time. This means that you receive an uninterrupted and infinite supply of hot water.

Can you store the water your combi boiler heats?

You can’t store the heated water with just a normal combi boiler. However, you could invest in a storage combi boiler.

Storage combi boilers merge the technologies of system and combi boilers. You won’t require a large water tank in the loft space or airing cupboard either, as storage combi boilers have a small storage tank built into them. 

These boilers were once quite large. However, as technology has improved, you can now purchase wall-hung storage combi boilers.

Ready to upgrade your boiler?

Ready to upgrade your boiler?

Get a free, fixed price, no obligation quote for a new boiler from BOXT today.

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Upgrade to a combi boiler with BOXT

Combi boilers won’t require you to give up some of your airing cupboard or loft space for a water tank (or multiple!). Instead, you’ll have a wall-hung combi boiler that provides you with heating and hot water on demand.

If you’re looking to invest in a new boiler, a combi boiler might be the perfect choice for you. Simply head to our website for a fixed price on your new combi boiler, or take a look at BOXT Life - our new all-in-one boiler subscription. From just £35 per month, you’ll receive a brand new boiler and installation, smart thermostat, unlimited repairs, replacement and servicing and much more with the added benefit of no deposit needed or interest charged!