What is the primary purpose of a furnace in an HVAC system?

The primary purpose of a furnace in an HVAC system is to generate heat for a building. Furnaces are designed to convert fuel—such as natural gas, propane, oil, or electricity—into heat energy, which is then distributed throughout the building to maintain comfortable indoor temperatures.

When the thermostat detects that the temperature has dropped below the desired level, it activates the furnace. The furnace ignites the fuel and heats the air, which is then circulated through ductwork or via radiators into different spaces within the building. This process is essential for keeping indoor environments warm during colder months, ensuring comfort for the occupants.

While some HVAC systems do handle humidity and air circulation, these functions are typically managed by other components like dehumidifiers, air conditioning units, or fans. The furnace's primary role is distinct and focused specifically on heat generation.