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What Is A Combi Boiler?

A combi or combination boiler is essentially a high-efficiency water heater and central heating boiler in a single compact unit. It heats your home and provides hot water without the need for a separate water tank.

Combi boilers can directly heat water from the mains on turning on a tap. It instantly heats the water rather than being heated and then stored in a cylinder or a cold-water storage tank in the roof space.

The heating and hot water are delivered at mains pressure, which means you can get a powerful shower without the need for a separate pump.

Since they combine two household functions into one appliance, they are more compact than other central heating systems.

How do combi boilers work?

To provide instant hot water, combi boilers are on constant standby and attached to the mains water supply. Turning the tap on, the boiler is activated into action, and it heats the water in a heat exchanger, for on-demand hot water instantly.

The heating process of a combi boiler is same as a conventional boiler. But the expansion tank is contained in the boiler itself, so water is heated in the boiler before being supplied to the radiators.

The Benefits of a Combi Boiler

Over the past few years, combi boilers have become more and more popular boiler in the UK, with more than 70% of homes choosing to install a combi boiler, over system boilers or regular hot water.

Several significant features make combi boilers the most popular boiler type across the United Kingdom. In general, combination boilers are:


Combi boilers heat the water in small quantities, thus cutting downs the energy and fuel bills. They have a lesser carbon footprint when compared to a conventional boiler. Since they are far less complicated than traditional heating systems, its installations tend to be cheaper. Also, you can find the replacement parts easily in case any problem occurs.

More Efficient

Combi boilers are highly efficient as compared to old, conventional boiler models. Combi boilers are up to 90% more efficient. Thus, heating your home is more affordable when compared to conventional boilers. And replacing your boiler with a newer combi boiler could help you to save up to £300 annually on your heating bills.


You don’t have to wait for the water to be heated. Since there’s no water tank to heat up and store hot water, combi boilers can deliver the unlimited on-demand supply of hot water. Thus, combi-boilers are very convenient if many people are waiting to use the same bathroom one after the other. Unlike a conventional boiler, there is no risk of water running out since hot water is provided as per demand.


Central heating systems together with a combi boiler usually have less slush accumulation, since the water is piped directly from the mains and not stored in a tank where it can build up debris and rust.


The cold water that comes out from a combi boiler system is always healthy and safer to drink as it is supplied directly from the mains.

More Compact

Since you don’t need a separate water tank, combi boiler systems are a space saving boiler that needs much lesser space than the conventional heating systems, making it perfect for homes with limited space.

Less Risk to Suffer from Pressure Issues

Combi boiler systems generally don’t suffer from low pressure or air locks, as the hot water is taken directly from the water mains.

Easier to Service

The growing popularity of combi or combination boilers means that a majority of boiler engineers are skilled about its repairing and servicing. This makes it easier and quicker to find out expert engineers in your area.

Different Types of Combi Boiler

Combi boilers are also available in gas, oil, LPG or electric in a wide range of sizes.

Gas Combi Boilers: In the UK, natural gas boilers are the most commonly installed boiler. If you have a gas network connection to your home, it can help you to keep running costs down.

Oil Combi Boilers: For homes in the UK not having gas network connection, another popular choice is the Oil combi boiler. These boiler systems require a tanker of oil to be stocked outside your home which has to be refilled by a provider as and when it finishes.

LPG Combi Boilers: LPG refers to Liquefied Petroleum Gas, and it is a mixture of gaseous hydrocarbons, made from oil refining (34%) and from natural gas and oil extraction (66%). These setups are quite similar to the oil boilers, which means the boiler has to be equipped with fuel from a tank in your house and top up when running low.

Electric Combi Boilers: This type of boiler is somewhat different to the other boilers because it doesn’t need fuel to heat water; rather the water goes through an electric element similar to a hot water cylinder with an immersion heater. Electric combi boilers are a popular choice for homes which are not connected to the gas grid, and oil is either unworkable or too costly. It is usually not recommended for bigger homes because the amount of hot water they can produce and electricity is comparatively expensive.

Popular Combi Boiler Brands Available at My Bubble Bath

At My Bubble Bath, we stock a wide range of combi boilers from some of the market-leading brands, and we have the expertise and experience essential to help you make the best choice when choosing boiler for your home.

The brand you pick could have an effect on factors including your installation price, so it’s always best to consider makers when making your decision. Brands we offer include:

Vaillant- Vaillant is one of the industry’s leading brands and has been building heating solutions for several years. Vaillant has been providing heating solutions for households for more than 140 years. Regarded by many as an industry leader, this brand is usually recognized as a forerunner of the combi boiler.

They manufacture best-quality boilers with reliability and energy-efficiency in mind. The brand continues to create boilers that could both efficiently and effectively fulfil homeowner needs.

Ideal- With a strong set of internal values, Ideal is determined by a commitment to customer satisfaction. This company continually strives to supply boilers that are both diverse as well as energy-efficient.

With over a century’s worth of expertise and experience, Ideal has made their robust, ever-lasting mark in the domestic heating industry by delivering top-quality and energy-efficient heating solutions to a diversity of homes and central heating requirements.

Their boilers that are easy to install, use and maintain, and they make every effort to meet customer requirements across the globe.

My Bubble Bath offers a wide range of combi boilers from market-leading brands, available in different budgets, sizes and specifications to meet every home owner’s need for heating solutions!

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