You first need to determine what it is that you are referring to as an Air Handler, as you have also used the term Furnace in your posts.
A furnace is usually the terminology used for a gas heating unit that is inside of your home, that when attached to air conditioning, will also include an indoor evaporator coil box either on top of or under the furnace.
But, sometimes, the furnace can also be electric, at which point it is an electric furnace or in professional terms an Air Handler. The Air Handler or Electric Furnace will also have an evaporator coil included with it, if AC is involved.
So, to summarize: You either have an Air Handler/Electric Furnace, or you have a Gas Furnace. Either is an air handler, as it "handles" the movement of the air. (In my best Slingblade voice "Uh Huh..Umm Some folks call it a furnace, uh huh...ummm I call it an Air Handler...uh huh...ummm:laughing: