Wow... -31! That's got to be the North Pole, surely? Or the dark side of the moon?
GTA:SWcity: I wonder if a hot water bottle is good for the lungs? Because you can move it to wherver you want and keep it over your chest to keep it warm. Then again, what works for one person might not work for other people. Your story of sleeping rough sound horrific, but it made me think of how past experiences affect the way you sleep in later life. My dad didn't have heating as a child and (possibly) as a result of this he often sleeps with the window open, because he's become used to cold bedrooms. Or maybe he's just mad.
For the people who think a hot water bottle is old fashioned: actually, a hotty botty is a modern technological marvel. If you go back to the 1800s then I think you'd have a metal cask with hot coals in (as featured in the first Pirates of the Caribbean movie; the coals were then dropped on Mackenzie Crook's face). I was once in a room at an old people's home, where we were discussing how they slept as children. Many people had hot bricks from the oven, or even the grill from the oven, still warm from the evening meal, heating up their bed -- and with their sisters and brothers in the bed too!