Air handlers and furnaces aren't often installed together in Concord. If you use a furnace, you probably don't need to consider an air handler.
Air handlers are often linked with heat pumps and manage airflow around your house. Some units also have secondary heating and cooling components to assist the heat pump.
A furnace heats differently by sending hot air into your vents, which circulate it around your residence. Because furnaces use combustion chambers to make hot air, they don't need some of the parts you'll spot in a regular air handler.