I know someone who used actual sheeps fleece, washed and carded, for her batting. It was so warm! Her room had no heat at all and it kept her warm. Another really warm quilt solution is to use wool material as your quilting material. My grandmother made several using blocks cut from granddad's old suits, backed it with flannel, no batting and tied it. Very warm. Very authentic for old time style as these were made around 1900 and she had made several before then.