I have a Criterion Quantom 200 sleeping bag which is really warm for its weight, but for me it's a 5* bag rather than the advertised 0*.

Does anyone use the S2S thermolite liners? They are supposed to give an extra 8-15 degrees depending on the weight you choose. Sounds too good to be true for 250-400g of fleece? It would be great if it did give me an extra 10* or so for £60, (I'm tighter than a nun's chuff). Or should I stop mucking around and buy a -10* bag, which I imagine would look after me to -5 degrees?

I've got the Reactor one which is supposed to add up to 8 degrees. I can't say that I've noticed it to be any warmer than a silk liner and certainley for the extra bulk and weight ( similar cost ) over a silk liner I would say its not worth it. Also mine after a few washes is no longer 210cm x 90cm but is now about 170 x 90. Its more like a T-shirt jersey type material than a fleece. I'd honestley put the money towards a new sleeping bag.

I used one in a -3c bag at -12c (the weather took a turn for the worse) and I did not sleep, though I was on the edge of shivering. Not sure if it added +8 but it did something.

I have started taking a pair of Rab Powerstretch trousers which are wearable when not inside the sleeping bag, I find this more versatile.

Sol escape bivvy does the same ( claims it's a 10 degree bag) and is more adaptable as you can get in your bag in dirty clothes )

Lazarus wrote: ↑Tue Dec 28, 2021 1:56 am Sol escape bivvy does the same ( claims it's a 10 degree bag) and is more adaptable as you can get in your bag in dirty clothes )

I have noticed the knited liner just make the bag. Feel warmer to first touch. And may be add a little but of warmth as they drape close to you.
The sol liner is an intresting filth barrier, but you may start to feel clammy. I once, fully dressed & wearing insulated jkt with water proofs ontop , got into a damp vag*. All was well , warm and dry next morning.

* Err, bag, I thought I'd leave that in.

TBH I'd be concerned that using my SOL inside a sleeping bag would mean the latter wouldn't loft well, thereby limiting its performance somewhat.

Out of interest, what sleeping mat are you using? Bag ratings usually assume a decent insulated mat.

Bearbonesnorm wrote: ↑Tue Dec 28, 2021 11:15 am Out of interest, what sleeping mat are you using? Bag ratings usually assume a decent insulated mat.

Exped Synmat, I think they're good to below freezing? I was in a tent as well and was wearing my merino négligée

Exped Synmat, I think they're good to below freezing?

Yep

you may start to feel clammy

was not warm enough to get to that point but its not going to be as breathable as sleeping bag or fleece liner

TBH I'd be concerned that using my SOL inside a sleeping bag would mean the latter wouldn't loft well, thereby limiting its performance somewhat.

i only use synthetic stuff and whilst its likelu /possible it impares the bag the two together were warmer than the bag alone [ In my non scientifically valid trial]

ScotRoutes wrote: ↑Tue Dec 28, 2021 11:14 am TBH I'd be concerned that using my SOL inside a sleeping bag would mean the latter wouldn't loft well, thereby limiting its performance somewhat.

How is the SOL going to impair the loft of a sleeping bag more than the 60-100kg person it’s wrapped around?
Cold weather explorers and high altitude mountaineers pretty much always use a vapour barrier bag liner that’s pretty much the same as the SOL.

I have been using the Sol Escape to uprate my bag for the winter for a few years and find it to be excellent, probably gives an extra 3-4 degrees.
Do not confuse the Sol Emergency bag with the Escape the emergency bag is not breathable.

Hmm, going by woodsmith's reply I'll give the liner a miss. I figured if I know I'm going to be snuggly down to say, -5c, then other than the odd very cold night I would be warm throughout the winter (in the UK at least).

The two choices that spring out are, Alpkit Pipedream 600, cheaper option. Or, I stick with what I know and go for the Criterion Quantum 450. A fair bit dearer, but 300g lighter and I'm guessing, a bit higher quality?

I know generally you get what you pay for with down bags. Does anyone use either of these two? Would be pleased to hear any opinions, or alternatives come to think of it.

How about buying something like a Cumulus 150 quilt and using it in combination with your existing bag?

Bearbonesnorm wrote: ↑Tue Dec 28, 2021 9:54 pm How about buying something like a Cumulus 150 quilt and using it in combination with your existing bag?

That was something I was going to mention Combined with a PHS Minimus 200 I'm good to -5/6C so with a warmer main bag it shouldn't be a problem to get much lower. The main problem might be getting hold of one! Cumulus themselves no longer ship to the UK and resellers like Backcountry.scot haven't had them in stock for some time. You can also use it as a summer bag/quilt. The newer style Cumulus quilts are a bit wider as well.

At that temperature rating for uk use I use a synthetic bag.
The predominant weather in winter is on the whole wet and windy. If it’s not raining, the grounds usually wet and condensation abounds in single skin shelters or tarp arrangements. Synthetic bags are imo that little bit more robust and reliable in such conditions.
Yes you can protect a down bag from damp and arguably you don’t even need to bother to do that on short trips.
I just find synthetics to be more reassuring because you don’t need to protect them so much.

Bearbonesnorm wrote: ↑Tue Dec 28, 2021 9:54 pm How about buying something like a Cumulus 150 quilt and using it in combination with your existing bag?

I'm thinking about this, it would work out cheaper and more versatile. Only negative is it would be a couple of hundred grams heavier than the equivalent 'bag.

Whitestone, I take it you don't get any reduction in the loft of your minimus when the quilt's on top?

Rob S wrote: ↑Wed Dec 29, 2021 8:18 pm

Bearbonesnorm wrote: ↑Tue Dec 28, 2021 9:54 pm How about buying something like a Cumulus 150 quilt and using it in combination with your existing bag?

I'm thinking about this, it would work out cheaper and more versatile. Only negative is it would be a couple of hundred grams heavier than the equivalent 'bag.

Whitestone, I take it you don't get any reduction in the loft of your minimus when the quilt's on top?

Not really - the quilt is pretty light plus it's just laying on top rather than being tucked in constricting things.