A/c unit in an outside wall?

Ideally you would put it high since cold air sinks. Most manufacturers list the minimum clearance from the A/C to the ceiling. But you also have to consider the electical outlet, and also you would not want it close to your body. Bottom line is you put it where its most feasible for you, even if you have to put it under a window,which is what some people do.

There's a couple concerns. First, window AC draw air from the sides, and dump the heat out the back. So, it might not work if it's a very thick wall.

Second, higher is better in terms of cooling. Cause the hot air is on top, and cold air will naturally fall.

This is Turtle

Put it in the window and have the window latch pinned down to hold it in there. You can have the outdoor supports to help to hold it. Then if you need out because of a fire you just pull the latch pins in the window and then push the window unit out. Then your out that away.

Now always put a window unit away from bed areas and about 3 foot high. Anything else is personal Opinion.

TURTLE

What he said.

Just to clarify, in light of what others said- you only need/want to cool where you are in the room. That's not clinging to the ceiling, but way lower down.

Because of noise, you don't want it right next to you. Nor do you want to be in the path of varying temperature discharge.

HTH, J

I put mine high above the bed, because I had to remove brick and removing brick at the top was easier.

But I have a small table fan on a table blowing cold air toward the bed from opposite the wall unit. I highly recommend the set up.

Sensible solution and much easier than cutting holes in the wall. You can drill though the sash to make a locking pin that is easy to remove. If flames are licking at my ass, I don't care if the AC falls to the ground, I want out.