Bivy and Sleepinng bag liners?

[xXlojackXx]

Does anybody use a sleeping bag liner by itself inside their bivy in 35-45 degree weather? I was thinking about going lighter that way this September when temps usually drop to 38-48 degrees at night. I run an Alpine bivy, BA Aircore 4.1 R value, and was thinking of picking up the Sea to Summit Reactor Extreme as a liner for the bivy. Anybody do the same and what're your thoughts?

 

[muleman]

I've not used or seen that liner but think I'd be cold. You would also have no margin if there was a cold snap.

Sea to Summit says it can be a Summer stand alone bag. Have you used it durning the summer by itself? How warm was the ambient temp? How warm did you sleep?

 

[xXlojackXx]

I don't own that bag liner. Just wondering if anybody else has any experience with something similar.

 

[_Nick_]

You would also have no margin if there was a cold snap.

My main concern as well. You'd probably be fine if weather was 45 degrees at night. 35 degrees and I know I would be cold, no question. Might even be a bit cold at 45... bivies stop drafts pretty well, but don't keep a ton of heat in... you'll still lose a lot of heat from convection without insulation.

 

[mrmorton]

I did exactly what you just said. I lined a SOL bivy sack with a Reactor extreme liner from sea to summit and ended up staying dressed in my pants and jacket all night long to stay warm. It was not worth the weight I saved. I regretted it completely. I had a pad as well. It only got down to about 40 at worst. Dont do it. Being light is nice but the weight is worth carrying.

 

[xXlojackXx]

Well, that is what I wanted to hear

 

[COR]

In regards to the liner, The Thermolite Extreme for example...You need to pull one of those out of the package before you assume it's "warmth"...50 degrees MAYBE. I have the Extreme and it serves to keep my quilt clean more than anything. It would not be very good as a stand alone or with a bivy...in fact when used in the summer on hot nights I get a "cooling efect" from it.

 

[Beendare]

I've used what was essentially 2 sheets sewn together...and then another time a thin microfiber liner on different backpack bowhunts in the Hawaiian islands- they worked well. There a guy could just sleep in his clothes and be fine as it didn't get that cold- just wet.