Types of Central Heating Systems
There is a wide range of central heating systems available today, however, they can all be classified as one of three main forms – a conventional gravity fed system, a high pressure system that works off the mains or a combination boiler system. If you are looking to upgrade or replace your central heating it can be hard to decide which might be the right system for your property, so we’ve taken a look at each type and its pros and cons.
Combination boiler systems
The combination boiler central heating system is easily the most popular today. These systems don’t require a feed tank, expansion tank or a hot water cylinder because they heat water as and when you need it. This means that they require a lot less space and are also economical – they only heat the water that you need.
- A combi boiler heats water on demand requiring no tanks within the loft space
- Electronic controls paired to your boiler
- Mains supply fed directly to the combi system
- Modern thermostatically controlled radiators sized accordingly
As with the other systems, combination boiler systems also have their drawbacks. The main one is that their flow rates are often quite low as the water has to be heated as it travels through the boiler i.e. there is no stored hot water to fall back on. This means they are unsuitable for homes with two or more bathrooms as the simultaneous use of two outlets will decrease the flow rate even further
Conventional gravity fed systems
These central heating systems use a boiler – either a regular boiler or a system boiler – to heat both the radiators and the hot water. The hot water circulates around the system and is then stored in a hot water cylinder until needed. The water that travels into the boiler for heating often comes from a feed tank or expansion tank in the loft space of the house and it ensures that the volume of water in the system is always at its optimum level.
In addition to the feed tank, there is normally a larger tank present as well that replenishes the hot water cylinder when water is used around the household. Water from this tank is drawn down into the system by the force of gravity alone – hence the name of the central heating system. The main drawback to this type of system is that you need loft space for the two tanks and an airing cupboard or similar space for the hot water cylinder.
High pressure systems
These systems supply mains pressure hot water through the taps in your home. Water is drawn in from the cold water mains and is heated by your boiler. It is then stored in a storage tank (called an unvented cyclinder) until required. When you open a tap in the house, cold water from the mains forces the heated water into the central heating system and out through the tap. The pressure at the tap is the same as the pressure of the mains which in most cases is a lot higher than you would normally experience.
These particular central heating systems are great if you have a high mains pressure to start with but if the mains pressure is low then the system is unsuitable. They can also be costly to install and some authorities require a certificate of annual maintenance to be submitted to them.
As already mentioned the combination boiler system is becoming very popular in homes today although in some circumstances these systems aren’t suitable. Each of the central heating systems has its pros and cons so you need to decide what features you require before deciding on the system for you.