To install a single-package air conditioner such as the "Unico Next-F 8 HP PVA", it is generally not necessary to make openings in the walls to discharge the air, as these units are designed to be used with an exhaust pipe that passes through a window. However, if you have a model that requires fixed installation, such as some split-type air conditioners, then openings for the air and drain pipes may be necessary. For the model in question, it is likely that only an exhaust pipe through the window is required.