Sleeping bag liners

Josh of the Bushveld wrote: I finally managed to find a Sea To Summit silk liner at a non-ridiculous price (and bought it).
Now to use it...

Hi Josh
How much does it add in terms of warmth to the Lite K-way bag?

I don't think it adds much warmth TBH, I bought it more to protect the bag, and chose silk because its lighter and packs up smaller (than cotton or synthetics)

FYI... I made an interesting discovery while in the USA last week. The temp ratings on sleeping bags are interpreted as follows:

comfort = temperature comfortable for a female
limit = temperature comfortable for a male
extreme = temperature at which a woman should survive before getting hypothermia (only for 6 hrs!)

Very interesting, thanks!

ASL is quite correct; another interesting factoid is that the EN13537 sleeping bag rating standard only applies to sleeping bags with a limit rating (ie comfortable for an adult man) above 0degF (-18degC); not a major consideration unless you're shopping for a winter escarpment bag. What does need to be considered though is that while many manufacturers use the EN rating system, they do not always make it clear whether they are quoting the limit or extreme rating, or even the comfort rating in the case of a sleeping bag specifically designed for women. You'd be wise to be check before you liberate your hard earned cash.

Not sure if this post should be here, or under the K-way extreme Lite post.
Mods, please move if necessary.
Lower Injasuti Cave, 12/9/2015
Groundsheet- 360*Thermal Emergency blanket- 335g
Mattress- K-way compact self inflating- 578g
Sleeping bag- K-way extreme lite 500 bag- 470g
Liner- Sea to Summit Reactor liner- 248g
I also took a sheet of some sort of coated nylon, 340g.
It was very misty and damp, and I covered the whole lot with the nylon sheet before I got into bed.
After I had been in the bag for a while, there was condensation between the sleeping bag and the coated nylon, so I took the top sheet off.
I wore only boxers for the whole night, (and buff and beanie).
Minimum temperature went to 8.4. I was very comfortable the whole night, and never felt cool.
Interested to see what temperature will be comfortable in that set-up, and what effect thermals will have.

On our 2-nighter to Vaalribokkop cave, I took the k-way Extreme Lite 500, a very light ripstop inner which probably has hardly any thermal value, and a bivy bag.
The temperature was not extremely cold, but the wind blew on both evenings, and there was a considerable chill factor.
On the first night I slept in just the bag and the inner, and boxers, thermal top and beanie, and I got cold until the wind dropped, and then was fine.
On the second night I used the same as above, but in the bivy bag as well. I was toasty warm, and woke up at about 12 (I think) and the wind had dropped. There was a fair bit of moisture between the sleeping bag and bivy bag, I got out of the bivy bag and used just the sleeping bag and liner. Warm for the rest of the night.

PS Are these sort of posts helpful, or irrelevant and unnecessary?

Thanks Papa D.

I for one am still building my understanding of what works/is needed for optimum Berg hiking in light of the range of conditions likely to be encountered, and have found your in-field reports useful. I do think each of us is different in our ability to keeping warm, and use your assessments as a guide rather than a target.

Did you measure any temps during the two nights?

Some pics of your k-way Extreme Light bag (TC 12C/ TL 8C/ TE 2C), bivy and liner may also be useful.

Hi Andrew
Unfortunately I did not measure any temps i was on a light quest for this hike!!
I would estimate upper single digits but with a wind chill though.

Here's the bivy bag: www.vertical-endeavour.com/forum/44-gear/295-bivvy-bags.html?start=20#65650

The Extreme Lite bag: www.capeunionmart.co.za/k-way-extreme-lite-500-down-sl

The inner is the same shape as the bivy bag, made of very light ripstop nylon, and with a half zip down one side. weighs 111g, more to keep the bag clean than for any thermal value.

Of course this is just speculation, but I think I would not have been cold with the Sea to Summit Reactor liner.

Cheers
Papa D

I have a sea to summit dupont thermolite reactor that I bought in 2008 .they said it should give 5 to 7 degrees extra warmth. I know see that kway and first ascent are offering  thermolite heating liners for 799   and specs state it adds warmth  up to 15C more  once inserted in the bag. Is there any real performance  difference with my old sea to summit thermolite reactor  and these new thermolite heating liners sold at k way and first ascent that claim to make the bag 15 degrees warmer .my old thermolite sea to summit only claimed 5 to 7 degrees but the products look so similar .any explanations?are the new thermolitea using better quality materials etc? ..THANKS Ivan