Portable air conditioners?

I have a back office in my house that gets very hot. I’d like to put an air conditioner in the window so I don’t sweat to death but the windows don’t open all the way out.

Either I can replace the window with one that will allow an air conditioner placement or I can get a hole cut in the wall to make a sleeve for an air conditioner or I can buy a portable air conditioner.

Which one would you choose? Right now the portable air conditioner seems to be least complicated and most inexpensive solution.

Portable would be the easiest no doubt but it is probably the least effecient as well as cumbersome. You have to put it on the floor(or on somthing) near the window, thus taking up space, then you have to run a big tube out the window. The tube radiates heat back into the room and, having a non conventional window, you have to figure out how to seal up the open window to keep even more heat from re-entering the room. Depending on what kind of outside wall you had (brick, vinyl, wood, etc.) I would either change the window out or put a hole in the wall.