What is a Combi Boiler?

A combi boiler is short for ‘combination boiler’, referring to the fact that it controls both your central heating and your hot water. It controls everything from one compact box, usually in the kitchen or bathroom of your home. This means that you don’t have to find room for a separate hot water cylinder in your property as with a conventional or system boiler. This is a huge benefit if you have limited or no loft space at all, for example.

The combi boiler simply heats the water as and when you want it, straight from the mains supply. This economical way of providing hot water, rather than heating up a whole tank that you might not use, is one of the reasons that it is currently the most popular boiler option. It also means that there is no limit to the amount of hot water you receive. Using a conventional system, once the hot water is gone you have to wait for the whole tank to heat up again.

As combi boilers are a more streamlined approach to providing hot water and heating for your home, installation usually takes much less time than with other types of boiler. This means you can be enjoying the benefits of warm rooms and hot water from your new boiler sooner.

What Size Combi Boiler Do I Need?

Combi boilers tend to range from an output of around 18kW to 40kW and sometimes even higher. Generally speaking, bigger houses with little insulation, a large number of radiators and more bathrooms would require a combi boiler with a higher output and small, well-insulated properties with one bathroom and just a few radiators would find a model with a lower output suitable.

It is also important to also check the flow rate for hot water. This is given as a litres per minute figure, and you will need a larger LPM if you intend to have two showers running at once, for example. If you have more than one bathroom, it is certainly a good idea to consider a combi boiler with a higher flow rate.

There are some circumstances when you might consider a conventional or system boiler, rather than a combi boiler. Houses with three or more bathrooms or where a lot of different people are using hot water at the same time might find issues with pressure if they used a combi boiler. Similarly, if your water pressure in general is low, a combi boiler might not be the best option for you.

If you have any questions about combi boilers, don’t hesitate to call us on 0330 055 2210.

How Does a Combi Boiler Work?

A combi boiler keeps the water in your radiators hot, allowing them to heat your house. The water flows through the boiler where it heats up, and then through your central heating system. From there it returns back to the boiler where it re-heats it to the optimum temperature again, ready to flow back through your radiators. The boiler works with your thermostat to provide warmth at a constant temperature of your choosing, re-firing every so often to make sure the water remains hot when your heating is on during this recycling process.

When you need hot water, the boiler sets to work heating the flow from the mains, which is why it takes a few seconds for your tap to run warm. Conventional boilers provide instant hot water, once they have been initially heated up, but only carry a limited amount of hot water at any one time. The hot water from a combi boiler is unlimited, and you only heat what you use, which can be much more efficient than other methods.

Because the hot water flows at the same pressure as the mains supply, it means you can enjoy powerful showers which might not be possible using some other methods.

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