Just as it says, the girl has a small heater in the flat. It sometimes does get cold in winter (last year the temperature dropped to around 10 degrees) and especially when you come out naked and wet after a shower with only a towellette to keep you covered.
The best way to learn is to do first hand research. Go give a heater a try and you'll see what I mean. And please report back (on the girl that is).
