Best warmth-to-size ratio sleeping bag?

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WittyUsername

Forager
Oct 21, 2020
173
60
38
Kent
Hi,
This has probably been asked before but I couldn’t see it in previous thread titles.

I’m after a 0°C sleeping bag comfort rating (around that mark, anyway) that packs down as small as possible.

Any help would be much appreciated.
 

gg012

Full Member
Sep 23, 2022
377
214
43
SE
I can't provide exact models etc but there is no magic to it, most down bags rated for zero degrees will be of a similar size and weight. You can pay more and save some weight and pack size by choosing higher fill power down but you may end up chasing diminishing returns

Sent from underground
 
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Moondog55

Forager
Sep 17, 2023
116
48
72
Geelong Australia
Using 7D fabric combined with 900+ down will do that, but do you really want something that fragile for bushcrafting?
More information needed from you, your age because sleeping metabolism drops after 35YO and for every decade after 35 you need to go 5C warmer, your fitness levels because that counts, are you on the larger side or tall and very skinny, how much of a safety factor do you need and will you always be sleeping in a double skin tent? Then comes the painful subject of budget, PHD can make something ethereal that weighs less than nothing and becomes a black hole when stuffed but costs half a universe or at least a couple of mortgage payments.
Packed bulk minimisation almost certainly means no zipper, are you sure you can live with that? My overstuffed Macpac Firefly [ I added an extra 100 grams of 800+ down after the first use] is about that if I wear my UL down parka and use my bivvy sack but it needs a 5 litre stuff sack, and the bivvy needs about 2 litres packed volume.

PHD for comparison


Anything is possible with enough money; almost anything anyway.
 

Pattree

Full Member
Jul 19, 2023
1,318
737
76
UK
I don't want to speak out of turn but I don't think that bag gives the best warmth to weight ratio by a long way
I would agree with this point. The mummy type is popular for good reason.
The Snugpack range is fitted with a removable (or variable) gusset along the zip so that the volume of air to be heated can be reduced.
I can’t recommend my SP Chrysalis* but they’ve got that volume thing right. There is also a clip to shorten it for a small person or a child.

* These (at least mine) were made in China and bear no comparison to the British made Snugpaks.
 
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Lean'n'mean

Settler
Nov 18, 2020
701
414
France


Going to go for this one I think. I much prefer the square end and ability to open it out, compared to the mummy-type bags.
The lack of baffles, the thin insulation & the inability to close the wide top opening will ensure you'll most likely be shivering in that under +10 °C. And at nearly 2kg it isn't light weight either for what it is.
The best warmth/size ratio has to be a mummy type bag.
 

Moondog55

Forager
Sep 17, 2023
116
48
72
Geelong Australia
There are a couple of lightweight options that work for some people.
One of them is the old climbers half sack [ elephants foot ] combined with a jacket of parka.
While a full sleeping bag is warmer you already have the jacket as part of your normal clothing.
My own half sack is a home sewn monster using 200GSM Quallofil and Goretex. Made it a long time ago for Alpine climbing and as a ski-touring Oh-**** bag.
For non winter use you can get away with as little as 65GSM and modern fabrics are almost as weather proof as first generation G'Tex and at a fifth of the weight.
The flat sleeping bag in the link is probably no worse than a woollen blanket as far as warmth goes but might be more wind resistant but at the weight not something I'd want to carry far or in cool weather.
 

Minotaur

Native
Apr 27, 2005
1,605
235
Birmingham
Buy one of the army sleep systems.
I use a (Dutch?) bivvy bag, a tiny vango mummy bag and a liner which seems to work well however no idea what the temp drop it has gone to is.
Also check what you sleep on as that where the cold is coming from.
 

Watch-keeper

Life Member
Sep 3, 2013
93
50
London
You could also look at down quilts, some of them are pretty light. For something around 0 degrees i think 450 grams wouldn't be impossible, of course you would be paying a premium for that. I have used enlightened equipment's 0 degree quilt and it came in at 550 grams and packed very small. There is also a company called Cumulus who make light down kit in Poland and make a 0 degree quilt weighing 600 grams.
 
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Kadushu

If Carlsberg made grumpy people...
Jul 29, 2014
868
945
Kent
Thinking outside the box for a moment: you could make significant thermal gains with a decent inflatable sleeping pad without adding much bulk. Just a thought
 

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