What to consider when looking at combi and system boilers
Before you take the plunge on a combi or system boiler, there are a few things you should factor in and think about.
Combi boiler drawbacks
Can’t meet high demand for water
Heating water on demand is really useful until you want to use two different showers at the same time. The water pressure will then drop, and you might regret not going for a system boiler with a cylinder that can store water.
Unsuitable for properties with weak mains pressure
You should make sure your home has strong mains pressure before you decide to get a combi boiler. This is because if it is weak or inconsistent the water coming out of your taps will be the same.
Might not be compatible with old pipes
Older heating systems were designed for a supply of water that was significantly weaker than it is today and so your pipes may not be able to handle higher mains pressure.
System boiler drawbacks
Take up more space than a combi boiler
With a system boiler as well as the boiler unit itself, you will also need room to accommodate the cylinder.
Hot water cylinder insulation
If the cylinder is not well insulated, the water will start to cool down quickly. This means more energy will be required to heat it back up again which will push your heating bills up. So, be sure to consider insulation if you are going for a system boiler.
Size of the cylinder
How much hot water is available to your home before it needs refilling will be determined by the size of the tank. This should equal the demand of hot water in your home.
Hot water is not instantly supplied
When the tank runs out of water you will have to wait for it to fill up again before you are able to access more hot water.
Should you go for a combi boiler or system boiler?
The most important factor when choosing between these two boiler types is the hot water demands of your household. For smaller homes with less residents and one bathroom, a combi boiler makes the most sense for you. You will be supplied with hot water access instantly from a highly efficient boiler unit that should help you lower your carbon emissions and save you money on your energy bills.
As beneficial as combi boilers are for small homes, they are unable to provide a strong supply of water to more than one tap, bath, or shower at a time. With that in mind, if you have a bigger home with more residents and bathrooms then you should go for a system boiler.
Combi and system boiler installation
Prior to fitting a new boiler, the heating engineer should carry out a power flush. This will get rid of any debris, limescale, and sludge from the heating system to improve its efficiency.
Replacing a system boiler with a combi
Making the switch from a system boiler to a combi is a useful way to free up some extra space. Your installer will take out the cylinder and change the pipework so that the hot water can get directly to the taps. This job will take up to two days to complete.
Replacing a combi boiler with a system
If your combi boiler is not meeting your hot water demand then a system boiler is a good alternative. However, it could be that your combi boiler doesn’t have enough power so ensure it has the right output rating. Replacing the units is a fairly easy process, particularly if you are intending to have the system boiler fitted in the same place.
Swapping the combi boiler for a system one can usually be done in one day, but you will also need a cylinder and new pipework. It is important to check that there is enough space available for the hot water cylinder, as well as the hot and cold water piping, in a cupboard or loft space.