Air handlers and furnaces aren't often installed side by side in Saint Charles. If you rely on a furnace, you most likely won’t need to consider an air handler.
Air handlers are typically used with heat pumps and control airflow throughout your residence. Some systems also offer backup heating and cooling pieces to support the heat pump.
A furnace runs in a different manner by blowing heated air into your vents, which circulate it throughout your home. As furnaces depend on combustion chambers to create warmth, they don't have some of the components you'll find in a standard air handler.