Air handlers and furnaces aren't usually installed side by side in Fort Lauderdale. If you use a furnace, you probably shouldn’t need to consider an air handler.
Air handlers are usually paired with heat pumps and manage airflow across your house. Some units also offer extra heating and cooling components to help the heat pump.
A furnace works differently by sending hot air into your vents, which move it throughout your home. Because furnaces depend on combustion chambers to make heat, they don't need some of the parts you'll find in a regular air handler.