It has been abnormally cold in Japan. The room was good sized and not too far from Yokogawa station. However, the heater was not enough to warm up the room. I had 2 comforters and a blanket on top. It wasn't freezing in the room, but cold enough that you couldn't sit there and watch TV without a blanket covering you. That was with the heater on.
And there is no elevator, but I was on the 2nd floor. It looks like there are 5 or 6 floors, so I hope you get a lower floor.