I bought a new portable air conditioner for my condo. I bought this one: a/c. I want to use it to cool either my living room or my bedroom. My apartment is 1100 sq. ft. so I believe this should be more than enough to cool down either portion of the condo. However my condo is not A/C friendly. It has only narrow casement windows and one roof to ceiling sliding window in the living room. I am also not allowed to install a window mounted A/C. However, it does have these 3 inch holes in the wall in many of the rooms (presumably for ventilation or A/C). I heard some of my neighbors use those holes to vent their A/Cs. I wonder whether this is safe or not (fire, mold). If it is, can I just hook the hose into a 6 to 3 reducer? What material is good for this purpose: PVC, metal, something else?
I know there are ways to install portable A/Cs in casement and tall sliding windows but both seem too complicated. I was hoping I can just use a reducer and be done, but I want to make sure it is safe. BTW the condo exterior walls are concrete.The holes clearly lead to the outside (I can see the street through them)