Air handlers and furnaces aren't typically found together in Haltom City. If you use a furnace, you most likely won’t need to spend time thinking about an air handler.
Air handlers are usually used with heat pumps and control airflow throughout your house. Some models also provide secondary heating and cooling components to help the heat pump.
A furnace heats in a different way by pushing hot air into your vents, which move it around your home. As furnaces use combustion chambers to produce heat, they don't have some of the pieces you'll see in a regular air handler.