I use it in the bedroom where I don't have air-conditioning. It is under the window, Unfortunately my window is not so well insulating, but thanks to this heater i don't feel the cold coming in, and it can heat up the room (~ 5 tatamis) quite nice. I used a space heater before, but i didn't like it. I felt the cold air coming in. I am much more content with this oil-filled heater.