What’s the difference between boilers (combi vs system vs open vent)

Before you rush out and buy any central heating system or boiler, it is imperative that you look into the options available. This will help you to establish what will be most suitable and what system will be the most economical for your household. There are 3 mains types of boiler to choose from, all boasting a range of various qualities, from the shape and size of the boiler to the functionality and settings.

A common boiler choice for many is the Combi Boiler. Combi Boilers are an extremely popular boiler choice for gas central heating systems and they provide hot water on demand for your central heating system, radiator  and all hot water outlets. Combi boilers are an excellent way to save space within a property as they are compact in design. This is great for keeping them out of sight and tucked away in kitchen cupboards.

Combi boilers function by taking cold water directly from the mains water supply and heating it straight away. This is great for instant hot water to any outlet within the home. Space is saved with the installation of a combi boiler because there is no need for a hot water cylinder as the water is supplied directly from the mains. With a combi boiler in place you will not lose heat through the storage cylinder making it very efficient.

Combi boilers are also very efficient because the flow rate restricts how much water you can use at any one time, however this can make it unsuited to households that need to use more than one hot water outlet at once.  

If your household does have 2 or more bathrooms and your mains water pressure is low you might like to consider the installation of a system boiler. System boilers heat water from the mains, eliminating the need for a cold water tank in the loft. This is beneficial to homeowners who would like to save on space. This type of boiler does rely on a hot water cylinder in order to store the water but the boiler itself is compact, making for the installation process very neat and simple. System boilers are fantastic for busy households as they can provide high pressure water to more than one hot water outlet at any one time. This type of boiler responds quickly but if the tank is to run out of water you have to wait some time for it to heat up again. This is fine though if you endeavour to plan the hot water system around the needs and requirements of the family. System boilers can be quite expensive to install and repair, but if you have a large family this is a great, practical and cost-effective option.

Another option is to select an open vent boiler, which is a boiler that requires the use of two water tanks. There is a need for a water tank in the loft and a hot water storage cylinder which is usually located in an airing cupboard.  The tank in the loft draws water from the mains supply and then feeds the hot water cylinder. The water is then heated by the boiler and can be distributed to all hot water outlets throughout the property. Again because this boiler is cylinder driven, it might take time to reheat once the water has run out. But you can use taps, showers and baths in different rooms at the same time, which is a great bonus for larger families or households with more than one bathroom. This is a great inexpensive and economical solution if indeed you already have a water tank and a hot water cylinder in place. The only downside to installing an open vent boiler in a newer or smaller property is the amount of space you will lose to plumbing and heating systems. The system itself may also lose some heat into the surroundings, which is a disadvantage if you are attempting to be as energy-efficient as you can.

Assessing the benefits of each gas boiler may help you to find the right system for your home and the most energy efficient option for the household. Combi boilers, system boilers and open vent boilers are all condensing boilers which means they are far more energy efficient overall thus installing a new boiler can really help to reduce energy bills, especially if your existing boiler is over 10 years old.This is because new boilers utilise the heat that is usually lost within the system, making them enormously economical.

Finally when choosing your new boiler, you should consider updating yoheating controls. A functional, energy-efficient boiler coupled with fully modern and functional heating controls and heating accessories can help you to fully customise and manage your central heating system, helping you to save money on utility bills and allowing the household to be as energy-efficient as possible.