There are two types that I've looked at-window units, and in-wall units. The window units fit into a window, with "ears" at the sides to fill in any empty space. The in-wall units are fitted into a space in a wall, and usually have a sleeve that they slide into. The sleeve is mounted through the wall, supported on the outside and the unit slides in.
Both types are available in 8K and 10K units and with 110V power.
Why does the in-wall unit cost ~$150-$200 more than the window unit for the same specifications?
Would there be a downside to using a window unit as an in-wall unit by framing my own sleeve and making trim for the outside and inside of walls of the room?
Or, do I need a sleeve at all? After all, when the window unit is in a window, the exterior of the unit is exposed to the elements as much as it would be when it is installed as an in-wall unit?
Is it worth it for energy savings to look into getting a 240V unit even though I only need 8 or 10K?