The answer to 'air handler or air handler' is that an air handler and an air handler are the same thing - they are the indoor unit of a central air conditioning or heat pump system that circulates and conditions the air in a home. The air handler contains the blower fan that circulates the air, as well as the coil that cools or heats the air. The main difference is that 'air handler' is the more common term used in the HVAC industry, while 'air handler' may be a less common or outdated term.
Air handlers come in a variety of sizes and configurations to match the cooling and heating needs of different homes. They can be installed in the attic, basement, or closet, and are typically connected to the ductwork that distributes the conditioned air throughout the house. The air handler is a critical component of a central HVAC system, working together with the outdoor condensing unit or heat pump to provide year-round comfort.