Originally Posted by zim
8 to 10 hours of sleep would be a dream! (pun intended) But I did get 7.5 hours of suspended snoozing last night, starting at 18 degrees and ending at 14. Went in at 4:30 for a pee break and to throw more wood into the stove.
The top of my legs were a bit cool, but my butt and back were slightly sweaty from laying on the pad and wearing cotton. I aired out my clothes, and then headed back out to the cold with a fleece blanket to supplement the 20 degree bag. Slept for another 2.5 hours before the daylight, chirping birds, and chill drove me inside.
While I can't compare it to an underquilt, I like the HHSS so far... and hammock camping in general. Didn't wake up with a back ache for once!
So you slept 7.5 hrs from 18F to 14F and during some of that time your back was warm enough to sweat? ( and all of this with no tarp? ) When you finally woke up chilled, was it your back or something else? Actually, looking back I see you say the tops of your legs were a bit cool, so I guess you are mainly going past the limits of your bag. Still, did you notice a cold back or butt anywhere during the night?
It does not look like you need an UQ, unless of course you just want one. And if you had one working perfectly, sleeping without a tarp or a sock to block the breeze might have made you a lot colder than you would expect. Sounds to me like you are doing about as well as could be expected with this system. By adding the HH bubble pad, you are going about 15F lower than I ever did, unless I added insulation down below(never have added a pad yet). And if it turns out your back/butt never did get cold, then you have at least another few degrees to go before the system gives up.
It would be interesting to see how well you would do without the pad, or plus maybe adding some unworn clothing down below. You might sweat less with just the pad and space blanket, or maybe not. I only say that because sweat has not been a problem for me, but YMMV.
You have managed quite the improvement from that 1st night!