An air handler contains the components that move the air throughout your home, called the blower. Air handlers can work with an air conditioner and houses the indoor coil, used to cool and heat your home depending on which system it’s running with. They are not the air conditioner or the furnace but instead work with those devices to move the air throughout the building, whether hot or cold. You may have dampers, filters, mixing chambers, and more in an air handler. In short, air handlers help direct the conditioned air throughout the building to heat or cool the building.