How to Hook Up Split Air Conditioners in the Walls

Set the condenser unit on the condenser pad in an appropriate location outdoors, ideally close to where you'll install the indoor component, in a spot that is protected from the sun.

Mount the indoor unit. Place the bracket on the wall in a high location that adheres to the manufacturer's requirements. Generally there should be 6 inches of clearance at the top and sides of the unit. Use a level to make sure the bracket is level, and mark the locations of the screws. Drill holes in these locations and secure the bracket to the wall with screws and a screwdriver.

Cut a 1½-inch hole in the wall near the outdoor unit, using a hole saw or a circular saw attachment to a drill. Cut a similar hole on the interior. This is where the conduit and connecting pipes will run.

Place the evaporator, or indoor unit, on its bracket according to the manufacturer's instructions.

Run all lines from the indoor unit through the hole in the wall to hook up to the condenser, following the manufacturer's guidelines. The piping delivers cool air to the indoor fan unit, which works to replace the warm air in the house with cooler air.

Contact a contractor to complete remaining steps, unless you are an electrician who's EPA-certified to handle refrigerant. A contractor or electrician will connect the compressor wiring. He will also activate the system's refrigerant. He may also secure the compressor and check for leaks in the system.