The Pros and Cons of Different Boiler Types
There are three main types of boiler:
- Combination boilers.
- System boilers.
- Conventional boilers.
You’ve probably also heard of a condensing boiler – this isn’t a type of boiler but rather at boiler technology. Most modern boiler types whether they are combination, system or conventional boiler will be condensing boilers. Condensing boiler technology essentially uses the waste heat from the flue gases to pre heat water entering the boiler meaning the efficiency of the boiler is improved. Efficiencies of 90% can be achieved with condensing boiler technology.
Part L1 of the building regulations does state that gas boilers installed after 1st April 2005 and oil boilers installed after 1st April 2007 must be condensing boilers. However, if there are technical difficulties and it would be too difficult to install a condensing boiler, non-condensing boilers can be installed.
Combination boilers are often called combi boilers. With a combi boiler, there is no need for a hot water cylinder or water tank in the loft as they provide heat and hot water on demand.
Advantages of combi boilers
- Because there is no need for water tanks and hot water cylinders, installation is easier and hence cheaper than other types of boiler.
- Combi boilers are the most efficient type of boiler as there is no heat loss from the hot water tank.
- Because combi boilers offer heat on demand hot water, there is no need to set the hot water to come on and there is no need to worry about hot water running out.
- Combi boilers take up less room than other types of boiler.
- Hot water is supplied to showers at mains pressure.
Disadvantages of combi boilers
- Because combi boilers heat on demand, there can be problems when using more than one tap at a time. For larger households where there is more than one bathroom, a combi boiler may struggle to provide hot water to several taps or showers at the same time.
- It can take longer to fill the bath with a combi boiler as water flow is reduced because the water is heated on demand.
System boilers are also known as sealed system boilers and, unlike combi boilers they do have a hot water cylinder but, like a combi boiler, there is no need for a water tank in the roof.
The advantages of system boilers
- System boilers allow larger homes to provide hot water to more than one tap at a time at a suitable pressure.
- There is no need for a cold water tank in the loft.
The disadvantages of system boilers
- You have to wait for the hot water to heat up before you can use it.
- You can run out of hot water if a lot of people are using it.
- You need space for a hot water cylinder.
- System boilers cost more to install and repair than a combi boiler because of the extra plumbing and hot water cylinder.
- There will be heat loss from the hot water cylinder meaning they are not as efficient as combi boilers.
Conventional boilers are sometimes known as open vent, regular boilers or gravity fed systems and need a hot water cylinder and a tank in the loft.
The advantages of a conventional boiler
- They are good for larger home where there is a need for hot water from more than one tap i.e. when you have multiple bathrooms.
The disadvantages of conventional boilers
- They don't offer heat on demand - you have to wait for the water in the cylinder to heat up.
- You can run out of hot water if there are a lot of people using it.
- You will need room for both a hot water cylinder and a water tank in the roof.
- Installation is more expensive due to the need for a cylinder and water tank.
Choosing the right type of boiler
It is really important that you seek professional advice before choosing a boiler for your home. If you are replacing an old boiler, don't naturally assume that you need the same as you had before. A good heating company will visit your home, assess your needs and make recommendations based on your lifestyle. A boiler is a big investment so it is important to get it right!
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