Air handlers and furnaces aren't typically used side by side in Roanoke. If you rely on a furnace, you likely shouldn’t need to spend time thinking about an air handler.
Air handlers are usually paired with heat pumps and control airflow around your home. Some units also provide extra heating and cooling components to assist the heat pump.
A furnace runs differently by blowing hot air into your vents, which circulate it across your home. As furnaces rely on combustion chambers to make heat, they don't use some of the components you'll spot in a regular air handler.