https://www.serviceexperts.com/faq/what-is-the-difference-between-an-air-handler-and-furnace

Air handlers and furnaces aren't typically installed in the same home in North America. If you have a furnace, you most likely won’t need to think about an air handler. Air handlers are frequently paired with heat pumps and manage airflow across your residence. Some systems also provide extra heating and cooling pieces to support the heat pump. A furnace heats in a different manner by pushing heated air into your vents, which send it across your residence. Since furnaces depend on combustion chambers to produce heated air, they don't have some of the parts you'll see in a standard air handler.

What is the Difference Between an Air Handler and Furnace?

Air handlers and furnaces aren't usually used in the same home in Jacksonville. If you rely on a furnace, you likely don't need to consider an air handler.

Air handlers are typically linked with heat pumps and manage airflow across your house. Some systems also have secondary heating and cooling components to help the heat pump.

A furnace heats differently by sending hot air into your vents, which move it across your residence. Because furnaces use combustion chambers to create heat, they don't use some of the components you'll spot in a regular air handler.