Air handlers and furnaces aren't often found together. If you have a furnace you most likely don't need to think about an air handler. Air handlers are typically paired with heat pumps and help manage airflow throughout your house. Some models also provide secondary heating and cooling components to help out the heat pump. A furnace functions differently. Instead of an air handler, furnaces have blowers that move hot air into your vents, which circulate it all over your home. Since furnaces have combustion chambers and make heat, they don't have some of the parts you'll find in a normal air handler.