How do I decide which type of condensing boiler best suits my needs?

There are 3 different types of high-efficiency condensing boiler:

• Combi
• Regular (a regular boiler is often also referred to as a “traditional” or “conventional” boiler.)
• System

Each type delivers all the benefits of high-efficiency technology, but which one you choose will depend on several factors, including your property, your lifestyle and the professional advice from us as we are CORGI (gas) and OFTEC (oil) registered installers.

What is a combi boiler?

An example of a central heating and hot water system layout using a combi boiler:

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The high efficiency condensing combi or combination boiler is an ingenious space-saving idea, and an increasingly popular choice in UK homes. In fact, combis now account for well over half of all the new domestic boilers installed in Britain every year.

The major difference between a combi and any other type of boiler is that a combi eliminates the need to store hot water - so no hot water cylinder in the airing cupboard. It is both a high-efficiency water heater and central heating boiler, combined (hence the name) within one compact unit which usually sits in the kitchen or utility room, or sometimes in the airing cupboard. The space savings result from the fact there is no hot water storage cylinder, cold water storage cistern or other familiar components of a regular (conventional) heating system.

The further benefits of this are a significant saving on hot water costs, and the fact that hot water is delivered through your taps or shower at mains pressure. So you can enjoy powerful showering* without the need for a pump. Another combi benefit is that it can generally save you money on installation time and costs, since no tank in the roof space means less pipe work and a shorter installation time.

*a thermostatically-controlled shower safeguards against sudden changes in water temperature.

What is a regular boiler?

An example of a central heating and hot water system layout using a regular boiler

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If you are replacing an older model of boiler, the chances are that you will have a regular (conventional) boiler. A typical conventional system incorporates a boiler and extended controls, a feed and expansion cistern, and a hot water cylinder (usually in the airing cupboard) which is often fed by a cold water storage cistern located in the loft.

*a thermostatically-controlled shower safeguards against sudden changes in water temperature.

What is a system boiler?

An example of a central heating and hot water system layout using a system boiler with a pressure hot water cylinder

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An example of a central heating and hot water system layout using a system boiler with an unvented hot water cylinder

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Unlike a combi, both a system boiler and a regular (conventional) boiler work on the principle of stored hot water - but a system boiler differs from a regular boiler in some important respects.

Firstly, many of the major individual components of the heating and hot water system are built in, which means that installation is quicker, neater, easier and more efficient.

Secondly, the hot water is pumped from the boiler through the system to the radiators and hot water cylinder, resulting in a fast response and more economical running costs. The system boiler removes the need for a feed and expansion cistern.