Air handlers and furnaces aren't usually found in the same home in Wheeling. If you use a furnace, you most likely shouldn’t need to think about an air handler.
Air handlers are typically linked with heat pumps and deliver airflow across your residence. Some systems also offer secondary heating and cooling pieces to support the heat pump.
A furnace runs in a different manner by sending heated air into your vents, which move it throughout your house. Since furnaces have combustion chambers to produce heat, they don't need some of the parts you'll find in a standard air handler.