You ask about a window unit. These units are designed with an
indoor and separate outdoor portion. As long as the outdoor
portion is outdoors, you can install in any appropriately sized
hole. It again comes with it's own "sleeve" , close the hole down
to the sleeve.


A window unit has grills on the side of the chassis as well as the
rear. If you block the side grills, you will cause the unit to not
operate correctly and it will short cycle. I already know this from
experience. I tried using a known good working window unit in a wall
sleeve, and it never worked right. I ended up getting another wall
unit.