I installed a second AC (15K btu)a while back. I used a 50 ft 10 gauge extension cord(cut end and hard wired it to the AC), snaked it through the ceiling, down the back of the frig., and into a cubby hole behind the outside shower fixture. The plug end sticks out of a hole in the fixture box. I just pull out as much as I need and plug it into the 20 amp park power. I cut the lip off of the roof vent so the AC gasket would fit. I had a smaller unit(7500btu) there previously, but left the vent lip and used 2 AC gaskets. It worked, but looked funny sitting up higher than the other AC.