Central Ducted Air Systems
Ducted air systems are the most common type of central heating and cooling used. If a home has a central air conditioner, heat pump, or furnace, it is a ducted air system. There are two main types: Forced-air Heating Systems and Gravity Heating Systems.
Forced Air Heating Systems
Almost 35 million homes in America are heated by natural gas-fired, forced-air heating systems, by far the most popular form of central heating.
With a forced-air system, a furnace warms air, an air conditioner cools air, or a heat pump either warms or cools air, then a blower forces the air through the system. Therefore, the same duct system can be used for both heating and cooling.
Below are images of the main components of a forced air heating system. Can you identify each? Drag and drop the image on to its name.
In a forced-air heating system, room air (cooler) is drawn by a fan or a blower through return air registers and ductwork, and passes through a filter (to remove any dust particles) into a furnace, where the air is heated. The warmed air is then blown back to rooms through a system of supply ducts and registers.
Click on the “play” button below to see how a forced-air heating system works.
Gravity Heating System
With a gravity furnace, convection currents (caused by the natural tendency of heated air to rise) carry heated air through the system from a furnace that is located on or below the main floor level. Gravity systems, somewhat older, do not have blowers, and tend to have very large air ducts; they can only deliver warmed air.
Press the "play" button below to see how a gravity heating system works.