I would like to know whether a down vest or a down jacket would keep me warmer, assuming they both have the SAME amount of fill.
In theory, focusing all the down on the torso area should keep you warmer, since that is where most of your major organs are.
However, it seems to me that if you do not insulate your arms, the blood that goes through them will cool down significantly. Being that your body will pump cooler blood into your torso because of uninsulated arms, this may mean you end up warmer in a jacket. Obviously I'm not a doctor, so I don't know if this is how the body works.
Let me hear your input.
-Sid

