When the winter hits and the cold begins to bite, we’re surely all grateful that we live in an age when central heating is the norm. Centred around and driven by a boiler, central heating systems are arguably the most important and beneficial parts of any home.
What’s surprising, therefore, is just how little most of us actually know about the boilers that do form the heart of those systems. Could you, for instance, explain what type of boiler your home has and how it works? Never fear if the answer is no, as below you will find a comprehensive guide to the three main types of boiler available, explaining how they work and what the main pros and cons are of each.
As their name reveals, conventional boilers are those which have been around the longest and were the only choice when central heating first came into existence. These boilers heat cold water from a storage tank – usually in a property’s loft – via cast iron heat exchangers and then store that water in a hot water cylinder.
Due to the need for both a hot water cylinder and a cold water storage tank, therefore, one of the main disadvantages of having a conventional boiler is that the entire system takes up a lot of space. What’s more, the many different elements of the system also make it more complicated – and therefore often more expensive – to install. Conventional boilers, too, tend to be less energy efficient than more modern varieties.
There are some situations and circumstances, however, in which conventional boilers are still the best choice. Properties with an older heating system, for example, will need a conventional boiler as that system wouldn’t be able to cope with the higher water pressure provided by a combination boiler. Properties with more than one bathroom, too, could be best served by a conventional boiler as they can effectively deliver hot water to several different areas of the home concurrently.
A more modern introduction, combination (or combi) boilers supply water directly from the mains and heat it instantly. That means that a heating system run by a combination boiler has no need for either a hot water cylinder or a cold water storage tank.
These types of boiler, therefore, are generally favoured in properties where space is at more of a premium. Installation is generally simpler, too, and as a result can also be significantly cheaper than in the case of a conventional boiler. Coming directly from the mains, hot water is also delivered at impressive pressure which means that a satisfying shower can be enjoyed without the need for an additional pump.
Combination boilers, however, are not suitable for older heating systems due to that very pressure. Possessing no hot water cylinder, either, there is no facility for the use of an immersion heater to provide hot water if and when the boiler itself fails. In general, too, combination boilers cannot supply more than one bath or shower with hot water at any one time.
Less common than either conventional or combination boilers, system boilers do feature a cylinder for storing hot water but have most other heating components built in. That means that, similar to combination boilers, there is no need for a cold water storage tank.
System boilers, therefore, have an advantage over conventional boilers in that they take up less space overall. What’s more, due to the presence of a hot water cylinder they can also serve more than one bath or shower at once, unlike a combination boiler. Comparably easy to install, system boilers are also often amongst the most economical to run.
Amongst the drawbacks of system boilers, however, is the fact that they do not instantly heat water in the same way as combination boilers and as such you can be left waiting for more hot water to become available.