So I gave my Downmat UL 7 another go at the Ohio Hang this weekend. Froze. Worse sleep than the weekend before. Cold spot VERY noticeable. Never got warm and I literally stayed up ALL night. One of my worst nights in recent memory, if not my worst.
After talking with Exped after my first trip, (who've been VERY helpful) Brendan suggested that I shake the mat to loft the down and that this must be done. Didn't see it performed in any of the videos I watched before purchasing but it made sense and based on another story from another member, it fit with the problem. So I shook it. On the side baffles I could feel my hands radiating heat touching the mat. Thought all was good. Gave my spare reflectix mat to my buddy who only brought a blue ccf (2.5 R) thinking I'd be fine this time.
Was so, so wrong. My 30* bag on top felt warmer than the downmat underneath.
I also noticed in the morning there was some condensation on the mat where my mid section was. It was frost, not wet. What could this indicate? I used the mat between the layers on my WBRR. Tried fully inflated and later up and let some air out thinking maybe I wasn't making contact with the crevaces between the baffles, but that didn't help.
Possible convection? I'd think that the mat retaining air and all, would be an impervious barrier as much as the ground would suck away heat, convection would and it's made to tolerate very low temps in that regard. But my body heat should've been trapped on the topside of the mat yeah? I'm at a loss, anyone want to chime in and help me troubleshoot this?