Combi boiler vs system boiler, which suits your home the best?

Updated on 3rd October, 2022 by Martin Astley

Looking to buy a new boiler for your home, but finding it difficult in deciding which boiler to choose? Then lucky for you this article will answer your all questions. We understand that choosing a boiler is a crucial decision because if you don’t give it detailed attention then you might be living with a boiler at your home that might not be happy with.

So, the first thing that you need to understand is the technical and operational differences between System vs Combi boilers. If you talk about the visual appearance both Combi and System boiler looks similar but have some huge differences in functionality. Let’s discuss this in detail.

What is a combi boiler and why to choose it?

We must comprehend both types of boilers independently to compare the running costs of system and combi boilers. The name “combination boiler” refers to a device that can heat and produce hot water simultaneously. It is a single, incredibly effective machine that provides hot water for both the heating and the canals.

The combi pulls water from the mains and heats it as needed each time a faucet or the heating is turned on. Consequently, a storage cylinder is not necessary. Combi boilers are very cost-effective since they automatically pre-heat the water and then reserve it.

To deliver hot water on demand and central heating water from a single device, they are often mounted to the walls and take cold water straight from the mains water supply, justifying its name. They are the perfect option for houses with limited space because of how little space they take up and their ability to run without a tank.

They are extremely well-liked because of how simple they are to install and maintain. Along with that, they are highly efficient and compatible if you require hot water in multiple bathrooms at the same time it will cater to your needs.

Pros of Combi boilers

Extremely Efficient

Combi boilers achieve at least 90% efficiency, making them incredibly effective. This not only means you can save your heating costs but that it will also generate less carbon than older boilers.

Compact Design 

Combi boilers do not require a tank because all of their internal components are contained within a single wall-mounted unit, unlike other types of boilers. They are therefore perfect for flats, bungalows, and other smaller properties because they don’t take up as much space. Their compact design allows them to be concealed easily.

Hot water supply on demand

The best thing about combi boilers is that they take water supply directly from the mains and heat it immediately providing you the ultimate convenience.

Denser water supply

The water supply you get from combi boilers is consistent and the density is also better than many other boilers.

Easy to install

Unlike many other boilers, it is simpler and less complex to install due to its compact design and size.

Cons of Combi boilers

Water flow disruption 

Well as mentioned above the combi boiler fulfills high hot water on demand, but sometimes multiple uses of hot water i.e., 2 showers at the same time might cause disruption in the water flow.

Slow-speed water flow

As the water is heated on demand you might need to wait for a few minutes if using the hot water at a high frequency.

High dependency on mains water pressure

As Combi boilers are highly dependent on mains and if a problem arises in mains that might affect the performance of the boiler.

Compatibility issues with the older heating systems.

Sometimes the high-density water pressure might affect your heating system if they are old resulting in damaged pipelines.

What are System Boilers and why to choose it?

System boilers differ from combi boilers through that they operate with a separate hot water storage cylinder. After being heated in the central boiler, the water is kept warm in the storage cylinder. Therefore, system boilers can quickly heat water for a lot of taps and showers.

The best system boilers use a heat exchanger to first warm the cold water from the main supply before transferring the heat from the gas to the water. The hot water is then moved to a storage tank where it is kept heated. Because the heating system is integrated into the system, this type of boiler gets its name.

Pros of System Boilers

Supplying hot water on demand

A system boiler can handle the high demand for hot water from multiple outputs at once since the water is already heated and ready for use.

Acquires less space

Because the system boiler draws water directly from the water supply, it requires less space than a conventional boiler because it does not require a cold-water tank.

Great density and flow speed

A system boiler can very much provide you with hot water as soon as you turn on the faucet. This is due to the system’s use of a pump, which enables the incredibly quick delivery of hot water that has already been heated.

Solar compatibility

Connecting the hot water storage tank to a solar panel system is quite simple, allowing you to re-heat the water using the sun’s free thermal energy. By adding solar to your system boiler heating setup, you may be able to lower your heating costs and carbon emissions.

Cons of System boilers

Delivers restricted volume of hot water

If you have a sudden need for a lot of hot water, you can use it all up and then have to wait for it to heat up further. You’ll need to set a timer exactly when you really need the water because the system needs to warm up in advance. You can find yourself without a source of hot water if your plans change.

Complex service and maintenance

System boilers have more components than combi boilers, so any problems that develop typically take longer to diagnose and fix, increasing costs and downtime.

Constant heat loss issues

When the water is heated and stored it might be at the risk of losing its heat, so make sure that your storage cylinder is well protected.

Conclusion:

To end the debate of Combi boiler vs System boiler you need to analyze and determine the hot water demands of your homes. Making things precise and simpler, if you have smaller homes for suppose consisting of 1 or 2 bathrooms then the Combi boiler is the ideal choice.

If you have a bigger home with two or more bathrooms and require hot water used multiple times, then the System boiler is ideal for you. Hope that through this article we have solved your problem in choosing the right boiler for you. Now you are well aware to make an accurate decision.

FAQS

Are system boilers better than Combi? 

It all depends on what you require, if you have smaller homes with 1 or 2 bathrooms then the combi boiler is the ideal choice for you. If you have a bigger home with two or more bathrooms then a system boiler is the ideal choice.

What is the difference between a system boiler and a combi boiler? 

A combi boiler instantly delivers hot water and heating. Since a system boiler lacks a hot water heat exchanger, it must work with a cylinder to provide hot water.

Is a system boiler more expensive to run than a combi boiler? 

It is expected that a combi boiler will be more efficient and so provide some savings if we compare system boiler vs combi boiler running cost.

Should I replace a system boiler with a combi boiler? 

Your home will gain a lot by switching to a combi boiler, as well as the environment. They supply hot water on demand and do not require storage tanks or cylinders. They are also compact and easy to install.

Is a combi boiler a Pressurised system?

The difference between a pressurized system and vs combi boiler is that the combi boiler should be installed as a pressurized system. But if you have the system boiler getting installed then you don’t need to install it as a pressurized system.