Originally Posted by BillyBob58
Please give us your thinking for the Exped in the UC. It is obviously working for you, I'm just not sure how. A pad in the UC is actually advised against by HH. You already described the "sticky" factor of both the HH OCF and the Exped keeping insulation in place. But here is what I am thinking: Your Exped causes a gap, normally a bad thing. However, you are placing high lofting insulation between the HH and Exped pads, which will close the gap. The gap caused by the exped greatly decreases any compression of down that would be normally caused by the UC.
If that is not it, what do you think is the benefit of the Exped in the UC, insulation wise?
I think staying warm at those temperatures means what he had didn't have any issues with air gaps. I suspect he had enough insulation between the bottom silnylon to fill it all in with only slight compression. Not enough compression to cause him to get cold. I thought he was using an Exped Multimat which I think is a fairly flexible piece of very thin closed cell foam pad that has nylon attached to one side.
Originally Posted by kwpapke
BTW, that was the motive for using the Precip jacket and pants as a VB. I carry them anyway during the Winter as a wind shell and for wet snow. Might as well wear them at night. They do breathe a little, I have no way of measuring exactly how much. All I know is my sleeping bag was much drier inside than my previous trip where I could feel the ice crystals beneath the bag shell, and I was warmer. They did feel a little clammy, but hey that's the whole idea, right?
You have it figured out and did great. There are tradeoffs and possibly being a little clammy versus staying warmer and keeping moisture out of your sleeping bag at those low temps are the biggies.