Sleeping Bag Liner - Warmth Gain

[markm]

G'Day,

I currently have a 900 fill down bag, standard mummy type arrangement and have been sleeping a little colder than i would like, not uncomfortable, would just like to be toasty.

Not big on layering up clothes wise as it makes me feel restricted, however i will sleep with thermals on.

Down to the question....has anyone had experience with a bag liner to add some warmth? if so what suggestions can you make as to what i should be looking for?

Cheers
Mark

[Grannyhiker]

I tried one of those silk liners (trying to bring a 30* bag down into the mid-to-low 20's) and it didn't seem to add any observable warmth. Also, because I toss and turn a lot, by morning I was so tangled up in the liner that it took me several minutes to get out of my sleeping bag. I had better luck wearing all my insulating outerwear inside the bag. Even then, I was on the edge of being cold. I ended up selling the 30* bag and buying a warmer bag.

[Reality]

Originally Posted by Grannyhiker

Also, because I toss and turn a lot, by morning I was so tangled up in the liner that it took me several minutes to get out of my sleeping bag.

That's a good point. It can certainly get a little awkward with a liner that's twisted...

Reality

[big_load]

I have a silk liner that's older than I remember. It does at a couple degrees of warmth, but that's about all. It's probably more useful for keeping the bag clean, but for me that doesn't justify the weight. I still use the liner for car camping, though.

[nogods]

In temps below 30F I've found that a vapor barrier liner substantially increases warmth, reduces sweating (even though you would think it would be the opposite) and keeps the bag from getting wet (which aids in keeping insulation value at its peak.)

[markm]

Excellent,

Thanks, I was concerned with getting tangled up in the liner, like a loose bed sheet I guess.

Perhaps I should be making a quilt after listening to the PB podcast on the golite, looks like the thing to do.

Cheers
Mark

[Buz]

I tried a liner for the warmth and clean thing. I am a side sleeper and for sure tosser and turner. After three nights, the liner was gone. Total mess inside bag, literally had to unknot the liner once, lol. But i don't like sleeping in many layers either, just base layer. Not sure on liner temp thing. Highly doubt 10 degrees. My liner was open side style, and if I was going to do it again, would use mummy style completely closed model.

I love to be toasty/hot sleeping also. My .02 would be to procure a warmer bag/system or possibly just add nice fleece/down clothes in your bag, not on you. That has been my solution, fill the bag, as I do better that way then wearing them. I bring an extra or warmer jacket if camping cold is possible, for use when not active and night sleeping.

[JimQPublic]

I agree 100% with nogods above. I would estimate the Vapor Barrier Liner adds a solid 10F, possibly more to the comfort range. I have used mine with long underwear and pile garments. The microclimate is warm and humid, but in my experience it isn't damp.

I used my homemade coated taffeta VBL quite a bit with a 20F rated down mummy bag, in a tent. With light long underwear I was quite comfortable at +10F, which is pretty typical for winter at 10,000 feet in the Sierra Nevada . The coldest I've experienced had overnight temps of -5F at 6:00 pm and lows probably about -15F. With polypro underwear, a light pile jacket, pants, and a balaclava I was able to sleep, but I certainly wasn't cozy.

I would be curious to see how a vapor barrier quilt would work. Using coated silnylon for the lining would add less than 1/2 oz. You could then use the same for most of the outer shell and do some sort of shingled arrangement to allow the air out when stuffing it. The concerns over windblown rain or condensation from a minimal tarp wetting the sleeping gear would be eliminated.

I suppose it would be easy to do a test run using a waterproof sheet under a conventional quilt.

[djtrekker]

I use a silk liner, mummy type, with a 15 degree down bag. I hike in VA/WV, very mild temperature and I sleep hot-hot-hot. I have used the liner on top of the bag (waste of weight I know - I'll be looking at that) as a warm weather sleep system. I think it adds warmth but I wouldn't guess at how much. It does get twisted around when I toss and turn, but the mummy cut of the liner minimizes the knotting up and twisting somewhat; still, it's an issue.
My main goal in using the liner is to keep the bag clean.
Conclusion: jury is still out.

[markm]

Think the decision has been made.....no liner it is, not really worth the extra weight if its only going to keep the bag clean and give me any real extra warmth gain,

Cheers to all,

[PBF Support]