A:Answer I just installed mine into a sliding window. I had to put some woods underneath to level the window frame and installed the bracket to support. it. Then I slide the window to the A/C unit as close as possible. I bought some plexiglass from home depot and cut to fit the gap above the unit. I used the insulation (comes with A/C unit) to cover any gaps, bought some additional adhesive insulation roll to patch any remaining gaps to prevent warm air coming inside. Another simple modification that I made is to get a round metal rod to lock the A/C unit in place ( there's a bracket attached on top of the unit, so I just placed that rod horizontally from one end of the glass window to the other end of the other side. That should prevent the A/C to fall down.