Conventional, Combination and System Boilers Explained

There are three basic types of boiler available – conventional, combination and system boilers.

A conventional boiler is the more traditional type of boiler which has a water tank or a water cylinder where hot water is kept. This means, the water is stored or heated and then used later. These are a good option because they typically run either from the mains or on a gravity system, meaning the water pressure will not alter no matter how many taps are being used at one time. Most households will already have this type of boiler installed – meaning replacement costs are minimal as the key aspects are already there. Typically these boilers will involve taking water from a feed from a tank either within a loft or a high up cupboard within the property to provide heat. This heat then warms a separate tank of water, usually within an airing cupboard. It is stored here for use as and when it is required. Just because they are classed as a conventional or traditional boiler, doesn’t mean they are outdated though! Brands such as Ideal boilers even offer the “Mexico HE” with built in temperature control and user friendly diagnostics. One of the big disadvantages of this system is the amount of time it would take to replenish this store once the hot water runs out. This option also takes up a lot of space within the home.

A combination or ‘combi’ boiler has capability to deliver both hot and cold water, as and when it is required without the requirement for cylinders or water tanks. Meaning they take up significantly less space than a conventional boiler. Some of the Worcester Bosch range can even fit within a standard sized kitchen cupboard – meaning no nasty boxing that doesn’t fit in with the decor is required – thus making them a great option for the design conscious! Combi boilers are very energy efficient as water is heated only as and when you need it. A combi boiler heats water from the mains on demand, when you turn the tap on, the boiler fires up and delivers hot water straight away. Combination boiler are ideal for small to medium sized homes or, if there is no requirement to have water running simultaneously. The downside to a combination boiler is the fact the water pressure may be affected should more than one tap be used at one time and they prioritise hot water above any other heating attributes in the home.

A system boiler heats both the central heating as well as a tank of hot water – just as a conventional boiler would. The upside to a system boiler though, is the fact they have the main components of heating and hot water built into them – making them not only more efficient but more space-effective in comparison to a traditional boiler. That being said, a hot water cylinder will still need to be stored and, as with a conventional boiler – once the store of hot water is used, it takes a fair amount of time to heat up again ready for use. System boilers are considered the quickest and easiest to install. These boilers are generally also compatible with solar systems. Many system boilers, such as the Vaillant ecoTEC will also be predominantly recyclable – making your carbon footprint and impact on the environment minimal.

Every household requires a hot water supply that is both reliable and cost effective. The key element in this is which hot water boiler you choose. With these differences in mind, its easy to be lead to think the efficiency and the size constraints are the biggest aspects to base your decision on, of course these are big attributes that should be considered but there are also many others. What should be considered before anything is how much hot water your household will require and when. The best way of explaining the decision process is by way of an example:

You are a shared house of 5 people, you want to maximise the space you have so the obvious choice would be a combination boiler right? Wrong.. what if you each work a standard 9 to 5 and all wish to take a shower when you get home from work? You are going to notice a difference in the power of the water as the water pressure would drop significantly if you have a combination boiler. You may also find, with this example in mind – your house temperature may have dropped fairly substantially as combination boilers prioritise hot water over other heating throughout the house. That being said, if you are in a house share of 5 people, and you each have a fairly small amount of space allocated to your living area, this temperature would rise back up again pretty quickly and your comfort may not necessarily be affected. Otherwise, a system boiler is the best option for you. If simultaneous demand is not in place for hot water, a combination should be a consideration. It is worth noting, in order to reap the benefits of a combination boiler it is almost essential to have good mains water supply pressure, with a system boiler this isn’t so vital with the provision of a storage tank in place.

Making the right choice is basically down to supply and demand. Of course, the upfront cost of a boiler may also have an impact on the decision but this is down to personal circumstance, contact us now for further advice and information on costings.