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What Type of Boiler Should I Choose?
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Types of Condensing Boilers

The law in England & Wales changed in April 2005, which means only a condensing boiler can be fitted as a replacement boiler or complete new installation. There are three types of condensing boilers. They are combi-boilers, regular boilers and system boilers. The main difference between these is the use, or elimination of, various parts within a typical system such as the hot water cylinder or the expansion tank.

Which Type of Condensing Boiler?
I live in a bungalow or a flat and have no loft space


I want to convert my loft and use it for a room or I have very limited loft space


I live house with several people. We need a lot of hot water but don’t want to wait for a hot tank to heat up Combi
I have a larger home with 2 or more bathrooms Regular or System
I live in an area which often has low mains water pressure Regular or System
I have a conventional central heating system and need to replace the boiler Combi, Regular or System


A combi boiler eliminates the need to store hot water and so there is no hot water cylinder in the airing cupboard. It is both a high efficiency water heater and central heating boiler. The boiler runs ‘on demand’ and provides hot water to the heating system in the house or flat. A combi-boiler requires high pressure from the mains.

System Boilers

System boilers are often referred to as sealed system boilers because the system is filled to approximately 1 bar pressure and sealed. They are connected to a hot water storage cylinder, usually installed in an airing cupboard. This type of boiler does not need an expansion tank in the roof. They are particularly good for homes with more than one bathroom because the combination of boiler and hot water cylinder can deliver hot water quickly to several outlets simultaneously.

Regular Boilers

If you are replacing an older model of boiler, it is likely that it is a regular boiler. A typical conventional condensing boiler system incorporates a boiler and extended controls, a feed and expansion cistern, and a copper hot water cylinder (usually in the airing cupboard) which is often fed by a cold water storage cistern located in the loft. They tend to take more space up in your home, but will usually have a less complicated design.

What We Recommend

We advise a condensing boiler that will either be a system or combi-boiler dependent upon your particular needs and the the circumstances and size of your home. Go to our Boiler Replacement and Central Heating pages for more information.

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