What is better, heating a room or heating yourself? When you are thinking on the last option, I have a very simple method. You can use a 12-volt electric blanket. The only thing you need to do is to make a slit in the center of the blanket to put your head through, and sew a collar around the hole with a strip of contrasting cloth. Take care with the direction of the heating wires inside the blanket. To close both sides, use Velcro. You can carry the battery in a small backpack. With a 12-volt lead (gel) battery of 12AH you can be warm for some time depending on the heating level you set.