What role does a heat exchanger play in a furnace?

A heat exchanger in a furnace is crucial for transferring heat from the combustion gases produced during the burning of fuel to the air that will be circulated throughout the home for heating.

When the furnace burns fuel, it generates combustion gases that are extremely hot. The heat exchanger facilitates the transfer of this thermal energy from these gases to the air moving through the system. As the warm air passes over the heat exchanger, it absorbs heat, causing the air temperature to rise before it is distributed throughout the living spaces. This process is essential for efficient heating, ensuring that the heat generated by combustion is effectively utilized to warm the home.

Other functions, such as removing air pollutants or generating electricity, are not performed by a heat exchanger in a furnace. The primary focus of a heat exchanger is on thermal transfer—not on air pollution control or electricity generation. Circulating air throughout the home is a function of the blower system rather than the heat exchanger itself.