Scratch & Dent Home Air QualityWritten You would need to realize that the space being cooled and the space the A/C unit rejects its heat into must be separated.  How this is done would be upto you.  If you want an extra hot bathroom and cut a hole int he wall and put the "outside" end of the unit in the bathroom then you can heat it up, and cool the space on the other side of the bathroom.  Otherwise you would need to somehow surround the "outside" section of the a/c and transfer its heat rejection and airflow to a place you don't mind, like pipe it outside, or into the attic, or the basement or something.Heat laws are heat laws.  It transfers the same whether in a window shaker, an expensive chiller, or from a stove to a frying pan.  It is not magic and bringing the AC unit indoors will not magically work, there is a reason they are mounted in windows.  They reject heat from indoors to outdoors.  Just like a stove to the pan, and from the pan to your food.  The AC unit is a medium of technology and mechanical components to transfer heat.

Written You may be able to rig up something whether the compressor-side air intake and exhaust are piped outside, but the efficiency will be low and you may risk burning out the compressor by working it too hard.If you want something you can install in a small opening, you might consider wheeled portable AC units which come with a flexible duct.If you're still determined to try it, note that window AC units have two sets of air intake & exhaust:the "inside" side that takes air from inside (usually through a large filter on the front), cools it, and blows it back insidethe "outside" side that takes air from outside, heats it (with the heat removed from the cool side) and blows it out the back.On a typical window AC unit the "outside" air comes in through vents on the side and top of the unit and is blown out the coils at the back. And they can't be the same duct, or else you will just get super hot air re-circulating through the unit.Written As you aware Window unit air conditioners are installed in an open window.

A large house or building may have several such units, allowing each room to be cooled separately.Written I'm unsure of the nature of this question but yes you can.  high efficiency ac unitYou can for example cut a hole through your bedroom door and install it through the door.  highest efficiency ac unitThe back would be facing the rest of the house and you would make your bedroom super cold.  average cost of ac unit replacementWhile at the same time dumping the heat into the rest of the house instead of outside.Written it depends very much on the nature of the rooms. But 9 out of 10, the situation wont be a feasible one. If your inside room has one of its walls adjacent to some crawl room or some unused room which is itself well ventilated then yes you can.