The answer to 'air handler or air handler' is that an air handler and an air handler are the same thing. An air handler is a crucial component of a central HVAC system that circulates air throughout your home. It houses the blower fan that pulls air from your return ducts, filters it, and then pushes the conditioned air through the supply ducts to the various rooms in your home.
Air handlers come in different sizes and configurations to match the heating and cooling needs of your home. They can be installed in the attic, basement, or closet, and are typically connected to either a furnace or an air conditioning unit. The air handler is responsible for distributing the heated or cooled air, so it's an essential part of keeping your home comfortable.