What is the primary function of a furnace in a heating system?

A furnace is primarily designed to heat air for distribution throughout a building or space. When the furnace operates, it burns fuel or utilizes electricity to generate heat, which is then transferred to the air. This heated air is pushed through ductwork and delivered to various rooms via vents, effectively raising the indoor temperature.

The furnace's primary role is distinct from other components in heating systems. For example, while it may seem that a boiler, which heats water for steam generation, serves a similar purpose, it operates on a different principle and is not the same as a furnace. Similarly, circulating chilled water for cooling is not a function of a furnace; this process is typically associated with air conditioning systems. A heat exchanger, although a crucial element within some heating systems, specifically refers to a device that transfers heat between two or more fluids. While the furnace may contain a heat exchanger, its primary function remains focused on heating air for distribution, which is what makes this answer the most accurate.