4 Season Sleeping Bag vs 3 Season Sleeping bag with liner

Hi Everyone

I would like to ask your opinion on sleeping bag liners, I specifically want to find out about the “warmth properties” of liners. I currently am looking at warmer 4season sleeping bags for when we go to the Drakensberg later in the year but the reasonably priced warm sleeping bags have a pack size of 30x25cm which is quite large IMO coming from my K-Way Zermatt 950 Eco.

I saw this liner on the First Ascent website and they say it adds up to 15° to your sleeping bag, so I was wondering if it would be worth it to buy a 6° comfort sleeping bag and just throw a liner in there for when I’m hiking in colder conditions. I’ve seen the liners are quite compact so it would definitely sort out the size problem and it would also allow me to use the sleeping bag in warmer summer conditions but I’m just concerned that the liner might not add the warmth that a 0° comfort sleeping bag would give.

If the liner is a bad idea, do you know anything about the Vaude Sioux 1000? I think for the price and the specs it looks like a great bag except for the size. There is also the First Ascent Amplify 1800 which has a much better pack size but it’s a South African made bag and I’ve read they aren’t too good?

Thanks for the help

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Hey Neil,

I don’t have any huge amount of experience with the warmer liners, but I have definitely got the sense online that people don’t see them as very effective. Which makes sense in some way, as there is not a lot of material there to trap air and help insulate.

Have never tried the Amplify 1800, but the 900 I have used definitely ran cold to me. In my experience the First Ascent stuff has all been fairly well made and priced though, but a bit heavy and not brilliantly performing.

If you are looking for something good but affordable and are willing to deal with the weight/admin, then I would give Aegismax on Aliexpress a look. A chinese sleeping bag manufacturer that has a pretty good reputation and makes a nice range of bags. The Nano 2, M series and G series in particular. There is the issue of it all being a bit vague about the ethical sourcing of the down, and they seem to often need a good wash to get there loft going at first. But for a decent low temp down bag at a good price I would definitely consider them.

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Thanks Jaxz!

We have the Amplify 1500 and it has kept me relatively warm on a really cold 0° night so I think the Amplify 1800, for it’s price is pretty good. I would love to buy more stuff from Aliexpress but I haven’t had a great experience with my last few purchases. We live in a rural area on a farm and shipments to this area either get lost or take forever to get here. Our trek is in 11 days so I decided to go with the Amplify 1800 for now as it has the smallest pack size (for its comfort rating) that I could find, with a good price and it ships within 24-72 hours, I’m still looking to buy another 0° comfort bag for my wife so I’ll see how this Amplify 1800 does and decide later on if it’s good enough for her.

I would still really like more opinions on this subject because a liner can really be helpful if it works well.

I don’t use liners. The main function of a liner is to keep your bag clean. They aren’t very efficient in terms of weight to warmth, are very fiddly and I generally don’t find them very comfortable when used inside a sleeping bag.

The claim of adding 15 degrees is an interesting one - adding 15 degrees to a 10c bag is very different from adding 15 degrees to a -40c bag.

As someone who hikes in the Drakensberg every winter, here’s a free tip: your sleeping bag is not something to mess around with. Winter is a lottery, it could be 0c overnight, or it could be -20c. I would not hike to the top outside of summer without something rated less than -7c. If you bag isn’t warm enough, I hope you are very close with your team mates :joy:

On a side note, if you can find something by Sea to Summit, Mountain Hardwear, Mountain Equipment or North Face - compare the specs to our local brands and you will see why I don’t buy locally made sleeping bags. A Mountain Hardwear Hyperlamina Flame has the same warmth rating as the locally made Drakensberg-winter-rated down bags, but weighs about 400g less, is considerably cheaper, is also water resistant. Notably it is also a synthetic bag, which gives you context how far behind the rest of the world we are.

Sleeping bags are expensive, so it is worth doing your research and buying a good one now rather than ending up with a cupboard full of sleeping bags that you used to use, before you found something better.


i use a liner only to keep the bag clean. i find that the temperature rating of liners are generally massively overstated. just imagine adding a layer of clothing that’s made from the same material as the liner and you will have a good idea of what it will bring to the party.
sleeping bags do become less effective the older they get and one has to be creative to prop up the sleeping temperature. pay attention to:
insulation from below (i.e. sleeping pad)
type of shelter (sharing a 4-season tent with a couple of homies will add a few degrees)
layers of clothing you can sleep in

One can also buy fleece material quite cheap and anybody with some skill with a sowing machine can make you a home made fleece inner - will be a bit heavy but does save a lot of bucks if you use it only on the odd occasion where you have to add a lot of heat

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100% agree - especially if you aren’t that worried about weight (i.e. you are very fit and not looking to push for big days). You can make a surprisingly warm liner that weighs about 1kg for under R100. I have used a polar fleece blanket on top twice (once in winter), and found it to be surprisingly warm for its weight on both occasions.


I have been using a K-Way Zermatt 950 sleeping bag, coupled with a liner for about 3 years now, and have always felt comfortable and warm. The coldest weather I experienced using this setup was below -10° at high altitude on Mt Stanley. I am generally a warm sleeper, so what works for me might not work for everyone else … but the combination of Zermatt 950 and liner is more than adequate for me, this also gives more than one benefit … reduced size and weight, and a liner also makes it easier to keep my sleeping bag clean, since I can just through the liner in the wash.

That’s great to hear. I’m also a warm sleeper so I’m glad that a liner makes a difference, can you maybe add what liner you are using?

The liner that I am using is the K-Way Coolmax Liner. It says on it that it adds +10°, which might be an arbitrary figure … but it works fine for me.

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I’ve been using a 2+ down sleeping bag combined with a sea to summit reactor it definitely adds lots of extra warmth!

I have to pitch in as I am also interested regarding people’s preference.

Winter vs Summer sleeping bags/liners:
Winter temperatures average below 10 Celsius with occasional lows < 0C. If you need extra padding at temp below this then I think any liner will be useless. In my experience, if synthetic material for insl was on par with down then I would recommend it. I have never employed any liners in any Antarctic or similar (snowbound) environments due to this fact. Rather try and choose a sleeping bag wisely (For an in depth review see: Choosing A Sleeping Bag – Feathered Friends ) Also remember if you pile on clothes the air within the sleeping bag takes longer to heat, if it heats at all (this is dependent on body heat). I take a reusable chemically activated pouch to heat the inside (https://heatinaclick.co.za/collections/orthopaedic-heat-pad) of my Deuter down sleeping bag (EN: Comfort 4C +/-6C) on subzero nights due to its -2C lower limit.

Summer Sleeping bag liners:
Now this is tricky…I have come to realise that a 4-10C comfort sleeping bag can get really uncomfortable in summer. I opted for a 500g lightweight Deuter sleeping bag and tested it out along the garden route…waaaaaay toooo cold. So in this case I am with you on the liner. The problem is do you dock out the R3000 for the expensive SeatoSummit top of the range and keep it lightweight (keep in mind this is 500g +350g=850g) or throw lightweight out the window and take along a fleese liner? Considering that most lightweight <500g SB are R1000, should you not just rather buy a summer sleeping bag For less than the R4000 within a range of 15C comfort and stick with it? I do not have the answer…sorry

To help you make up your mind I can only offer the following which helped me decide:
Review of best 2019 Sleeping bag liners & explanation of liner materials>

Review of Sleeping bags & an explanation on sleeping bag ISO/EN ranges:

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If you get weather in the Berg where you can use a 4 season sleeping bag, please invite me along as I’d love to test out my 4 season bag I took to Nepal.

Bottom line - it rarely (if ever) gets that cold in the Berg. I use a TNF Blue Kazoo 650 down bag rated at -10 degrees and it’s perfect. Ok, I’m also a warm sleeper, but still, chances of it ever getting cold enough to use a 4 season bag for you are slim. bag can compress to about 15cm high and about a 15cm diameter as well with the fitted compression bag.

Liners…mmmhh, agree with above sentiments. Use mine mostly to keep the sleeping bag clean. Don’t actually use it anymore, just wash/wi[e off all dirt before I climb into the bag. Also, I use tights (pants and top) so dirt isn’t much of an issue. This probably adds more warmth than a bag liner :slight_smile: . Seriously, they do add a couple of degrees, maybe 3 -4 deg C but I seriously doubt any more than this. So for the additional space they take, and the additional weight I’d rather leave them home. I usually take a bivvy bag along - mostly for wet conditions, but this little device is much more effective in keeping me warm than a bag liner would ever be. Same weight, a bit bigger but can be used for different purposes. And then I can save weight on a tent as well :slight_smile:

I’m referring to the bag liners with this sentence:
“Seriously, they do add a couple of degrees, maybe 3 -4 deg C but I seriously doubt any more than this. So for the additional space they take, and the additional weight I’d rather leave them home.”