What is Central Heating?

Central heating is a system used to provide warmth to several or all rooms in a building. The heat is generated from one area in the building, referred to as the central heating point, and then distributed throughout the building.

The heat from a central heating system is normally transmitted through forced air using ductwork, steam, or hot water passing through the pipes.

A central heating system is a common feature in the United Kingdom, where 85% of households depend on central heating to maintain comfortable room temperatures.

How does Central Heating Work?

A central heating system works by heating water or steam and forcing it through a network of pipes. The water or steam passes through radiators or convectors and then returns to the boiler to be heated again. As the water passes through the radiators, it gives out some of its heat to the surrounding air, thus warming the room.

An electric pump inside the boiler keeps the hot water flowing around the pipes and radiators, repeating the same sequence, thus effectively warming the building.

Can Central Heating Control Temperatures In All Rooms?

The central heating ideally generates heat and warms the different rooms in a building. However, in practice, the central heating should be connected to room control thermostats to cater for uniformity when heating.  This way, one room cannot overheat while the others are still cold.

How Does Central Heating Differ from Local Heating?

A central heating system generates heat from one point, in this case, a furnace or a mechanical room and then distributes it throughout the building. On the other hand, the local heating or joint heating system generates heat from a shared boiler plant. The heat is then distributed through a network of pipes to a community of households.

Which Energy Sources Are Used for Central Heating?

Heating sources for central heating systems are many and varied. The most common ones include wood boilers, gas boilers, air to the water heat pumps, and geothermal heat pumps.

Some households also use solar energy to fire their central heating systems. However, it is worth noting that this method requires extensive planning is expensive to set up.

When selecting the main energy source for your central heating system, some of the factors you ought to keep in mind are cost, availability, efficiency, convenience, and reliability.

While at it, it is worth mentioning that some heating systems use a single energy source, while others can switch energy sources for economic and convenience purposes.  That is to say, you can opt to install a wood-fired furnace with an electrical backup or an electric central heating system with a solar backup.

Oil and electricity are the most readily available energy sources for firing central heating systems in the UK. Natural gas is also used in some areas, while propane is mainly used in rural and cottage areas.

Solid fuels including wood, peat, and coal are also common. However, these fuels are inconvenient to handle, generate a lot of ash and are incompatible with automatic central heating systems.

Other energy sources used in central heating systems include local geothermal heat, which uses hot water and steam from a well to provide warmth in a building.

What are the Main Methods of Central Heating?

Central heating can be carried out in many ways. Here are some of the most common methods of central heating in the UK.

Warm Air Heating

Warm air heating works by drawing in air from outside and heating it over a furnace. The heated and pressurised air is then forced through ducts that run through the building, and as it passes, warms the building.

Warm air heating is better suited for small areas such as bungalows and small story structures. The method, however, will be ineffective and expensive for bigger commercial buildings.

Hot Water or Wet Central Heating

This method involves heating water using a Combi boiler or a hot water cylinder and using a pump to circulate it throughout the house via a network of pipes.  A hot water cylinder is perfect for large areas and commercial buildings, whereas a Combi boiler is efficient for small homes.

The circulating water system uses a closed loop, meaning the same water is heated and reheated again, thus reducing overhead costs.

Steam Heating

A steam heating system utilises the high latent heat given off when steam condenses to liquid water to heat rooms. For this method of central heating, each room is equipped with a radiator connected to a boiler.

As steam enters the radiator, it gives up its latent heat to the radiator and, as a result, condenses to liquid water. The radiator, in turn, heats the air in the room and provides direct radiant heat.

It is inadvisable to install a steam heating system in a single-family residential construction due to the high cost of laying the piping network.

Electrical Heating

Electrical heating or resistance heating converts electricity directly to heat. Electrical heaters circulate heat by blowing air across a heated element, mostly a coil rated at five kilowatts. The cold air in the room enters the furnace through return air ducts and is heated as it blows across the heated coil.

Electrical central heating is more expensive than central heating by combustion appliances using natural gas, propane, or oil.

Ground Source Heat Pumps

Ground source heat pumps use naturally occurring geothermal energy from the ground to heat buildings. Ground source heating pumps are designed for average low winter temperatures. Still, they can be complemented by other forms of heating, such as electricity when temperatures are extremely low. 

What are the Key Features of Central Heating?

Now that you know what is to know about central heating, let’s wrap up this guide by recapping the key features of central heating.

• The boiler pumps heated water or steam through underfloor piping networks or radiators. They, in turn, release warm air gently into your home and maintain optimal temperatures.
• Central heating doesn’t require any forced air movements. Therefore, it does not feature hot and cold spots, draughts, or noisy irritating fans. The heat comes out modestly and passively and warms fabric and other objects in the room.
• The overall process of central heating is highly efficient. Once the air temperature rises to the desired temperatures, the central heating is switched off. Meaning that no fuel is wasted, yet the heat will continue to be emitted from the radiators and pipes.
• Most modern central heating systems are fitted with thermostats and timers in every room’s radiator to allow for the precise control of temperature. This way, warmth is only delivered when needed.
• You can even programme the more sophisticated underfloor heating systems to control the duration and the level of heat supplied to individual rooms or zones.
• A central heating system that uses underfloor pipes to deliver heat to the rooms is only applicable to new homes or buildings under renovation. The reason is simple since the pipe network must be laid down before the floor slab is laid.
• On the other hand, you can install a central heating system that uses wall-mounted radiators in new and occupied houses.
• It is prudent to install the most cost-effective method of central heating. Geothermal heat sources are encouraged for their cost-effective nature and environmentally friendly compared to other combustive heat sources utilising fossil fuels.
• Electrical heating is mostly used as a backup for other central heating methods since it would be highly expensive to use it as the sole heat source in a building.