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