Air conditioners in RVs operate according to the same principles that guide a window-mounted RV in a regular home. You simply need to mount the air conditioner securely, ensure that the wiring is correct and keep the seals well maintained. If you have a knack for installing RV equipment, you should be able to do it yourself. Otherwise, you may wish to have a professional install it and observe how he does it so that you can perform similar functions more readily.
Select a good location on the roof of your RV that will fit your rooftop air conditioner. You want a spot that is strong enough to support it and doesn't have any obstructions such as lights in the ceiling below it. The edges of the air conditioner should be at least 8 inches away from the edge of the roof.
Cut a square hole in the roof big enough to fit the connections between the roof portion of the air conditioner unit and the ceiling portion of the air conditioner unit. Make sure you measure it precisely. Mark the locations where the mounting bolts will go as well.
Mount the roof portion of the air conditioner unit over the hole you have made. Secure it with mounting bolts at the locations you have marked
Install the bolts in the interior of the RV that hold the ceiling unit in place. Then mount and secure the ceiling unit.
Apply sealant to the points on the roof where the air conditioner meets the metal if you wish.
Connect the wiring to their proper locations in the ceiling unit. The wires should be coded by color, allowing you to match each one with its proper corresponding wire (black to black, white to white and so on)
Plug the ceiling unit connector into the roof unit.
Turn on the power supply to the air conditioner.
Turn the air conditioner on.
