We recommend using plexiglas.
Casement window portable air conditioner vent.
You can see how one homeowner did it in the video below.
Gulrear portable air conditioner window vent kit window slide kit plate for portable air conditioner adjustable length portable ac vent kit for exhuast hose of 13cm 5 1 inch 4 3 out of 5 stars 466 39 96 39.
However any type of material that will keep the hot air out and the cold air in will work.
It works by taking in air from a room cooling it and directing it back into the room venting warm air outside through an exhaust hose.
This would also work if you want to install an air conditioner in a sliding window as well.
Gulrear portable air conditioner window vent kit window slide kit plate for portable air conditioner adjustable length portable ac vent kit for exhuast hose of 13cm 5 1 inch 4 3 out of 5 stars 445 39 96 39.