. While it is quite possible to do, it's one of those "if you have to ask, you shouldn't do it" things. All you have to do is put the evaporator in an insulated box, but it's a lot harder to do than to say. You will need to know how to modify high-pressure piping/tubing and recharge the system (vacuum pump and manifold gauge set). . And refrigerant recovery equipment is required to do it right. In many places, you are legally required to have a license to work with refrigerants.