Lightweight 0 degree sleeping bag.

[cams]

Just came across Joe from zpacks new creation.

Crazy light bag/quilt setup. A long/wide -1* C runs 459g/$325, Multiple sizes and fill weights, $US300-350

Shortcomings are no hood and bottom zip.

Yeah, they are enticingly light, but his fill weights seem on the light side for the ratings.

[photohiker]

Yea, possibly. Looking for something to compare isn't easy, as these things have no hood.

Zpacks quilt Reg, Medium: 207g fill rated -1
OP Cocoon 400 Std: 400g fill, rated -4
WM Summerlite 6': 255g fill, rated 0
HG Burrow 40*: 200g fill, rated 4.5
HG Burrow 20*: 340g fill, rated -7

Yes, I know, EN13537 ignored in this post except for the OP bag

With the minimal price variations in the zpack range, it could be worth getting the warmer quilt rated to -7 with an extra 92g of fill in the reg/medium size like above for $20 extra.

[cams]

Yea, possibly. Looking for something to compare isn't easy, as these things have no hood.

True. And yeah, the fact you can customise them so much is great.

[blacksheep]

With so much heat loss through the head, and no hood...i have doubts.

[mattmacman]

With so much heat loss through the head, and no hood...i have doubts.

Beanie/ Balaclava and hooded fleece, will still be slightly colder but will be more versatile.

[blacksheep]

With so much heat loss through the head, and no hood...i have doubts.

Beanie/ Balaclava and hooded fleece, will still be slightly colder but will be more versatile.

I'm talking abou their temp rating. The manikin used to determine an accurate rating would loose all the heat through the "head"..not saying the product isn't fine for many applications, but how they give their temp ratings is not above questioning.

[photohiker]

I'm talking abou their temp rating. The manikin used to determine an accurate rating would loose all the heat through the "head"..not saying the product isn't fine for many applications, but how they give their temp ratings is not above questioning.

Apart from the OP bag, these are all US based cottage industry quilts. Questioning is helpful and valid, but EN13537 is not spoken over there, and even if it were, cottage industry wouldn't be able to pony up for the testing costs.

I suspect the ratings are based on seat of the pants and experimentation, height of baffles, quality of down etc.

I can tell you that my WM Ultralite overfill is too hot in most situations I've taken it. WM rate it at -9 and I've been too hot in it at 0C so this seat of the pants can be reasonably useful as long as you know if you sleep hot or cold relative to others. Most times I sleep without the hood anyway.

[Macca81]

With so much heat loss through the head, and no hood...i have doubts.

Ok im a bit over hearing this myth repeatedly on bushwalking forums... The head loses no more heat than any other part of the body. Having no hood will have no greater effect than sticking an arm out. A beanie/balaclava will cover 99% of the heat loss that would result from no hood on a bag and even without that you would still lose hardly anything.

[Macca81]

http://www.guardian.co.uk/science/2008/dec/17/medicalresearch-humanbehaviour
25 seconds after my last post and google pulls up this. Im sure i can find something from a science journal if i wanted too also...


Im all for good debate regarding temp ratings etc, but the reality is that a hood will only have a small amount of difference. Particularly on something like the above quilt which is designed for ultra light hikers who layer up to sleep and almost certainly are wearing a beanie at the least...

[ILUVSWTAS]

With so much heat loss through the head, and no hood...i have doubts.

Ok im a bit over hearing this myth repeatedly on bushwalking forums... The head loses no more heat than any other part of the body. Having no hood will have no greater effect than sticking an arm out.

Interesting comment. What facts are you basing that on? Im just curious as I believe the head looses alot of body heat!!

EDIT - I just had a browse through your link, thats interesting! BUT if im cold when im walking, i put a beannie on and im much warmer....

[ULWalkingPhil]

I just wear a beanie. Always have, never owned a bag with a hood. My beanie is about 10 or 15 years old. and only weighs 68 grams. Kept me warm in temps down to 0.

I know one thing for sure, If I don't wear a beanie when it's cold, I freeze. Same as my feet. I do believe that a lot of warmth is lost through your feet and head.

[photohiker]

I _think_ the reference to losing most of the heat through your head is that the rest of your body is already covered.

So it's right, but its wrong. Any exposed part of your body will lose heat according to circulation and surface area.

Blacksheep's observation is correct too, but we already know that quilt users pop on beanies and balaclavas etc to counter heat loss normally catered for by the SB hood.

[alliecat]

Macca is quite right - the head loses heat at pretty much the same rate as the rest of the body. The myth is a distortion of the fact that if the rest of your body is covered (but not your head) then the most effective thing to do to reduce heat loss is to put on a hat rather than add more clothing elsewhere. That's not because the head is in any way special, it's just because that's the only uncovered bit! The truth is that an uncovered head will lose heat much faster than a covered body - the important words got dropped somewhere along the way and we got the myth.

Damn - photohiker beat me to it

Cold hands hand feet (if already covered) are almost always the result of circulation problems, and adding more gloves or socks wont really help much - you need to get more blood to those areas. Actually, adding more clothing can sometimes make limbs and extremities feel colder by restricting the circulation even more.

Cheers,
Alliecat

[icemancometh]

the Z pack quilt/bag also looks narrow, even the wide one

climbing shoulders and propensity to sleep on one's side often means mummy bags dont r3eally work, least not for a good night's sleep in amummy
taken to opening my bags and rezipping them to make quilts like the z pack design anyway

The Z pack cold bag in long wide would be alright i reckon

[Mountain Rocket]

Cold hands hand feet (if already covered) are almost always the result of circulation problems, and adding more gloves or socks wont really help much - you need to get more blood to those areas.

I remember reading somewhere that if your hands are feet are cold it is because your body is pumping more blood to other parts of your body (ie. head/brain). It made sense to me when I thought about it. Your body would surely prioritize your brain over your limbs (hence frostbite?) and as you said adding additional clothing to those areas will often have little to no effect (and as you pointed out, it can actually be detrimental).

If it means anything... I for one am a firm believer in a good hood on a bag.

[Franco]

As a few have commented, it is based on a misunderstanding on what "if your feet are cold, put a hat on " is meant to convey.
Take note how often you will see folk with 3 or 4 torso layers on and yet no (warm) hat or gloves.
Chances are that they will sweat and be cold at the same time.
Even if your head loses exactly the same amount of heat as the rest of the body, that would mean that it needs the same amount of insulation

Blacksheep is correct in questioning the rating of a hoodless bag IF it isn't explained that they are meant to be used with some headwear.
Or to put it another way, if you add the headwear to the other bags in the list, than they would be warmer too.
Obvious to some but again not to all.
Franco