Understanding Hammock Underquilts or Underquilts Explained
Having a well fitted underquilt makes a huge difference. The difference that may mean a nights sleep or a freezing uncomfortable dangerous situation. Making sure the underquilt can achieve dead air to be heated is the goal. Having open ends is the biggest error I see. The ends need to be air tight, not folded or gaping. Next the underquilt itself needs to be up against the body with a minimal amount of compression. This compression increases the dead air capability.