If you are a serious camper, possibly facing extreme weather conditions, consider a mummy sleeping bag. These bags are warm, light and usually include a hood. They are meant to fit snug to the body and can usually be compressed more than other bags.
Sleeping bag linings are generally made of polyester, which offers the greatest value; cotton flannel, which gives you a bit more comfort; and a poly-cotton blend, which is very soft. Choose what feels the most comfortable to you.
Sleeping bags are filled with a variety of materials, from synthetic fills, like polyester, to down. Look for a fill that has the warmth rating you need and that can be compressed as much as you require, particularly if you’ll be backpacking.
Full-length draft tube
A full-length draft tube is an insulated flap runs the entire length of the zipper and prevents heat from escaping through the zipper coils.
Bags with quilted construction have the inner lining and the outer shell stitched together to prevent the fill from shifting. Since there’s no fill along the stitched through line, this can result in cold spots. More premium sleeping bags have offset quilted construction, which prevents cold spots.
If you like to be able to regulate your temperature and allow air circulation, look for bags with zippered vents along the side of the sleeping bag or near the foot box.
Hood and neck yoke
You can lose up to 80% of your body warmth through your head, so a hood and a neck yoke can reduce that heat loss and help you stay warm.