Air handlers and furnaces aren't typically used side by side in Albany. If you use a furnace, you likely shouldn’t need to think about an air handler.
Air handlers are often paired with heat pumps and deliver airflow around your residence. Some units also have backup heating and cooling parts to support the heat pump.
A furnace works differently by sending heated air into your vents, which circulate it throughout your home. Since furnaces have combustion chambers to produce hot air, they don't use some of the components you'll spot in a standard air handler.