I do use the top flannel sheet from my set during the winter. That does provide a little extra warmth. In my old age, using a flannel sheet as a bottom sheet just makes it too hard to move around. I used to have one of those soft flannel blankets and found that was a great help in winter underneath the quilt too. Oh, and I am a sock wearer too. Love my socks...just wore my bright green unicorn ones the other night...I love bright socks for my night time wear. Support hose during the day.