We were told not to open the window due the insects. In the night it was very heavy air in the room even if we had air condition on. Windows are covered with condensed water. In the long run this might cause damage to structure. Fresh air should be allowed in the room.
Had a great stay at Kurobe Unazuki Onsen Yamanoha. Breakfast and dinner were buffet style with many options - both traditional and western. Room was very spacious and was a lot bigger than we were expecting! Highlight was the outdoor Onsen. Would highly recommend - staff spoke good English and very friendly.