The landlord just put in a brand new AC unit and it works great except for one of the bedrooms isn't getting cool. It's a 9 x 10 bedroom. The master bedroom which is a lot bigger than the room that isn't cooling and it gets very cold. This doesn't really make sense since it is a smaller bedroom and it should be easier to cool than the master. We've checked and the vent in the room is blowing cold air but the room just never gets cold.

Does anyone know what the possible issue here is? I would like to try to fix the issue without getting landlord involved if possible.

Thanks!

The smaller bedroom possibly is further away from the a/c unit and is not getting enough of the cooling air. You should consult your landlord on this as it was his money that was spent and if it is not properly cooling he can contact the installer and see if they can come up with a workable solution.