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What Is A Combi Boiler And How To Choose The Right One For Your Home

What is a Combi boiler?

This is a Combination between a high-efficiency water heater and a central heating boiler, both forming as a single compact element. It is, therefore, in some way, an advanced type of boiler incorporating all the strengths of the other two types of boilers, the Regular and System boilers.

How does a Combi Boiler work?

The Combi boiler operates by drawing water from the mains, unlike the other boilers. Therefore, as soon as the hot water tap is opened, the system will be ignited, and the boiler will heat the water instantly and deliver it to the taps at the main’s pressure.

The boiler’s heat exchanger works by transferring the heat from the burnt gas inside towards the cold water and then delivers the heated water to the taps. This often has a delay period of seconds, however, to perfect this technology, the modern Combi boilers often have an inbuilt pre-heat system which acts as a reservoir keeping water at a certain temperature to ensure that at any given time, the system always has some elements of hot water. This ensures even more efficient hot water delivery.

How to choose the right Combi boiler

There are several factors to consider always when selecting the perfect Combi boiler. These factors often need to align with your needs as the buyer.

Therefore, some of the factors to consider include:

1. Determining the size of the Combi boiler needed

Combi boiler sizes are often proportional to the output of hot water. Therefore, when choosing a Combi boiler, one needs to assess and account for the likely amount of hot water that would be utilized in the respective homestead.
Average houses often require medium-sized Combi boilers of about 20 to 35 kW to produce enough hot water. However, as the sizes of the houses increase, so does the bathrooms and the need for more hot water output, and this would hence require a much bigger Combi boiler.

2. Determining the performance rate of the Combi boiler

Similar to the size, larger houses often require much faster Combi boilers for efficiency, whereas small houses may require averagely performing Combi boilers.

3. The price of the boilers and installation

The buyers always need to have enough money before purchasing the Combi boiler system. This is because money shortages might result in the installation of a substandard or unfitting Combi boiler to the hot water output requirements, which could result in catastrophic consequences and wastage of resources.

4. The difference between a Combi boiler and a condensing Combi boiler

A condensing Combi boiler is an advanced form of a Combi boiler. This is because the Combi boiler often loses the waste flue gases and the accompanying heat to the environment. In contrast, upon the installation of a Flue Gas Heat Recovery System to the Combi boiler, it becomes a condensing boiler, and it will now be able to capture the heat from the waste flue gases, recycle it and use it to heat new entering cold water. Thus, the condensing boiler will be able to heat water using little energy compared to that used by plain Combi boilers.


a new central heating installation


Are gas Combi boilers more efficient?

There are several types of Combi boilers installed all over, for instance, there are electric Combi boilers, Liquified Petroleum Gas Combi boilers, Oil Combi boilers, and gas Combi boilers. Nevertheless, the most installed Combi boilers in the UK are the gas Combi boilers.

This is because they are cheap to install since many households already have a gas line, they present a cheap operation cost, and they are thus more efficient compared to the others. The other types of Combi boilers often require complicated installation procedures and are often costly to maintain.

Nevertheless, for a household with no gas lines, the oil Combi boilers are always the best next option. All in all, the gas Combi boilers are always the best and most efficient of all the types of Combi boilers.


Get In Touch

We hope you have enjoyed reading our post, if you have any issues on your boiler or central heating system, you can get in touch by calling us on 07771 956641, we’re always happy to answer your questions.

Here at Harman Heating, we have been providing boiler and central heating services for customers in and around Northampton for many years. So, please call us with confidence. Our boiler and heating services including Boiler Service, Boiler Repairs, New Boiler Installation, Full Central Heating Installation, radiators Installation as well as Plumbing services. We look forward to receiving your call.