<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (July 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> A forced - air central heating system is one which uses air as its heat transfer medium . These systems rely on ductwork, vents, and plenums as means of air distribution, separate from the actual heating and air conditioning systems . The return plenum carries the air from several large return grills (vents) to a central air handler for re-heating . The supply plenum directs air from the central unit to the rooms which the system is designed to heat . Regardless of type, all air handlers consist of an air filter, blower, heat exchanger / element / coil, and various controls . Like any other kind of central heating system, thermostats are used to control forced air heating systems . </P> <P> Forced air heating is probably the type of central heating most commonly installed in North America . It is much less common in Europe, where hydronic heating predominates, especially in the form of hot - water radiators . </P>

What is the difference between central and forced air