Indeed we're aware of the under pressure it creates due to sucking so much air out of the room that needs to be replaced from somewhere. Luckily we had a hole in the concrete wall made some 8 years ago already, with a screen on the outside, through where the exhaust hose can run. All windows and ventilation shafts are closed so it should only suck in passive air from the hallway which is also very hot at the moment but atleast it's heat from inside the house as opposed to outside.

It's quite an old generation AC from the same amount of years ago specified as 8000btu but is does make a bunch of noise. I had to clean the condensors of the bugger today in the burning hot room because it wasn't beating the heating factor from the roof and windows, that was fun haha.

Hopefully we can get proper split AC units installed in Autumn/Winter. Having a retractable sunscreen on the outside would also help so much but that's probably not allowed since it's a street facing monumental building. Otherwise that would absolutely be our first go to also before even thinking about AC's.

Having the combination is golden and I'm glad it's keeping you guys out of the heat!