Just thought i'd share a little tip with you of what i do just before getting into bed on these really cold night its simple really just before getting into bed if you have an hair dryer just lift the covers and give a good blast with the hair dryer especially at bottom of the bed and also give the pillow then last of all in between the sheet the flat sheet and the duvet. i don't like using hot water bottles or electric blankets so i do this instead it works wonders. i have been doing this since my son was little, he is now 25 and does it himself in his own flat.
just thought i'd share that with you