Central heating describes the process of providing warmth to all or parts of the inside of a building through a single heat source located in one place. In many cases, for example with large offices and public buildings, the central heating system is part of a larger and more comprehensive HVAC system (Heating, Ventilation and Air Conditioning). Such HVAC systems are used to control not just temperature, but the actual internal climate of the building. Indeed, some buildings have automatic systems to control light levels too. Venetian blinds located inside sealed double glazing systems will automatically open and close throughout the day to adjust the amount of light coming in through the windows.

With central heating, the heat is generated in one central place and then distributed throughout the building. This methodology therefore differs from local heating where heating units in each room are used. A typical system for central heating involves burning fuel such as heating oil, gas or coal in a boiler or furnace. In a domestic house this boiler will often be located in the kitchen or in an airing cupboard. In a larger building like an office or public building such as a library or museum, the furnace or boiler will be in a dedicated boiler room. Electrical central heating systems do exist, but they are not as common as those run on fossil fuels. This is because such systems are only feasible where low cost electricity supplies, or geothermal heat pumps, are available. There are also environmentally geared central heating systems which are becoming popular with people who care about their impact on the environment. These use alternatives to fossil fuels such as solar power.

The heat generated in the boiler, either from the combustion of heating oil or by capturing solar energy, is then distributed throughout the building. There are various methods for doing this. One method is to pump air through duct work which runs throughout the structure of the building. Another method involves heating water in the boiler and then circulating steam, or more usually hot water, through pipes around the building. The pipes will lead to radiators which are mounted on the walls. Each radiator around the building will usually has its own controls so that the heat can be regulated in each room.

This is the usual type of system that is used in many homes across northern regions of the world such as Russia and northern Europe. Here, because of the temperate climate, most homes will have a central heating system built in. Air conditioning systems are not commonly seen in these regions because of the cooler climate, where air conditioning is seldom or never needed. Conversely, homes in warmer parts of the world such as south America, Africa and south east Asia will have air conditioning systems but no central heating.

Some people may think that central heating is a relatively new development. In fact, the Romans started to introduce central heating in the year 100 AD when they were occupying many regions of northern Europe, including Germany and Britain. Here, they constructed buildings heated by air which was warmed in furnaces and ducted through the buildings using pipes in the walls and spaces under the floors.