| In its truest sense, a household central heating | | | | Dry, or forced air, central heating systems use a |
| system consists of one heat source, such as a | | | | single gas or oil-fired furnace and a network of |
| boiler or furnace, and a network of ducting or | | | | ducts through which the heated air travels |
| piping that carries the heat to all the rooms in the | | | | throughout the building. Sometimes fans are |
| house. There is a growing selection of systems | | | | utilised within the system to create a more even |
| that do just that, from traditional radiator | | | | heat dispersal pattern, which is especially |
| systems, to modern underfllor and ceiling heating. | | | | important in multi-storey homes where the hot air |
| Here is a brief summary of the options: | | | | is always rising to the top level at the expense of |
| Although ceiling and underfloor heating systems | | | | the lower ones. Room temperatures can be |
| are often referred to as being types of central | | | | controlled individually using adjustable dampers in |
| heating systems, it is more common for them to | | | | the ducting. |
| use an independent electrical heating element | | | | Wet, or hydronic central heating systems use a |
| rather than a shared heat supply. Both systems | | | | boiler to heat water which is then circulated |
| work by using electrical heating elements or piped | | | | around the house through a network of pipes and |
| hot water built into the structure, surrounded by | | | | radiators. This is by far the most common type |
| insulation which reflects the heat into the room, | | | | of central heating system in use today. There are |
| rather than letting it escape into the ground or the | | | | two main types of hydronic system, namely |
| atmosphere. | | | | open-vented and sealed. |
| Electric storage heating systems are not central | | | | When water is heated, it expands. |
| heating systems in the true sense, as they use | | | | The main difference between the two types of |
| individual heating elements for each room. They | | | | hydronic central heating systems lies in the way |
| work by using a combination of an electric heating | | | | that this problem is dealt with from an engineering |
| element and insulating ‘fire bricks’, which | | | | perspective. Systems which compensate for the |
| can store and release heat energy over a | | | | expansion of hot water by using a separate feed |
| comparatively long length of time. The bricks are | | | | and expansion cylinder, which channels the excess |
| charged up with heat during off peak periods, | | | | water back into the boiler once it has cooled, are |
| when electricity is cheaper, and disperse this heat | | | | known as open-vented systems. |
| over the course of the day. | | | | |