Anomalies in insulation performance

[Travis Leanna]

Has anyone else experienced anomalies in their insulation capabilities?

My recent example: I was sleeping out under a Trailstar on a KookaBay DAM in a Montbell Spiral Down Hugger #3. The night was relatively calm, clear, and got down to around 40-45 F. I got cold. BWWWWAAHH?

I've been in this setup and various other setups in my Montbell bag in temps down to 30F and have been perfectly fine. In fact, the following weekend I camped in the exact same spot with the same exact conditions, except that it got down to 26F. I was warm.

I just thought that being cold at 45F was really strange. Anyone else have weird things like this?

[Greg Mihalik]

The insulation performed the same on both nights.

Your body did not.

[Travis Leanna]

You are correct, sir. However, the basic premise of quite large variances in *perceived* performance still remains! :)

I should have added something regarding seemingly tiny variances (metabolism, slight humidity changes, health , etc…) and how they can greatly affect how you feel.

[Eric Lundquist]

What you eat is a contributor to your body's ability to keep you warm at night. I also notice a difference of perceived warmth after washing up with a wet bandanna after setting up camp vs. just climbing in with all the sweat of the day's journey.

[Travis Leanna]

Eric,
I'm aware of the positive effect that eating before bedtime can have on the metabolism, but I was surprised by the 20F difference. I'm gonna start packing some jalapenos!

[Dan @ Durston Gear]

It's not really an anomaly because it's always like this, but I find my NeoAir adequate in winter conditions sleeping on snow. This night it was maybe 5-10 degrees below freezing at 5500':

[will sawyer]

Dan, what does the rest of your sleep system look like? and 5-10 degrees F or C?

[Dan @ Durston Gear]

For winter use, my sleep system is:

– NeoAir Small (9oz)
– 1/4" CCF back pad from my ULA Ohm under my feet
– GooseFeet Down Pants (7.3oz) containing ~3oz down
– My traditional (not UL) 600fp down jacket. This jkt is quite heavy (32oz) due to it's heavy shell fabric, cheap down and heavy feature set. I would estimate it's of similar insulation value as a Montbell Alpine Light Down Parka.
– GoLite Ultra 20 sleeping quilt (19oz) with 9.5oz of down. 9.5oz of down is more consistent with a 30F rating for quilts. For 2010 GoLite increased the down to 11oz in their 20F rated quilt.

On top of that I wear the liners from my boots or ski boots on my feet and I wear a toque.

I use the down jacket and pants for use around camp as well, so I'm carrying 28oz of sleeping specific insulation. I am wearing quite a bit of insulation to bed in these winter instances, but it's all down so it's not of that much insulation value beneath me. When I sleep on my side on the NeoAir I really don't notice much heat loss. That's what has surprised me.

Here's a picture from a snow cave last winter. It was a below zero in this cave because my water bottle froze solid. This is from when I had a full length NeoAir, but now I use a small one with a pad under my feet. I actually just wore regular socks on my feet this night. That's just a tarp under my NeoAir to keep my bag from contacting the snow:

The picture I posted in my earlier post was taken a later date when I was using my small NeoAir. The temps were -3 C when we went to bed and it definitely dropped a lot lower than that…likely in the range of -5 to -10 C.

Another member of our party used just a NeoAir also. He combined that with a warmer sleeping bag (not sure of the rating) and some light clothes. I'm not too sure on his specifics. Here he is blowing up his NeoAir:

[will sawyer]

awesome pics. I'm amazed that you can stay warm in those temps with a near and 20 degree quilt, even with the extra clothing.

Will

[Randy Nelson]

I just got the Allen & Mike Really Cool Backcountry Ski Book. book and it mentions doing something to generate some body heat before going to bed. They're talking about winter camping but the same thing applies in general. Warm up, go to bed warm, and your sleeping system has more to work with. Seems like pretty good advice but I'd never done it. I just try to not lose any warmth in the evening and then go to bed. Does anybody do this?

[Ike Mouser]

must have taken forever to build that cave.

[Travis Leanna]

Yeah, pretty sweet snow cave!

[Dan @ Durston Gear]

It did take a while….maybe 2 hrs. The bummer was that the handle for my shovel fell out of the back pocket of my pack on the way to this location so I had to dig it with just the shovel head.

Here's looking the other way at the entrance. I was able to enter and mostly block the door with snow blocks except for the vent at the bottom which I varied in size using the red shovel head. I also had a top vent of course.

I just like this pic. It's the next morning all packed up and ready to ski with 15cm (6") of fresh pow.

[Travis Leanna]

I need to get me some time in the mountainous (and snowy) northwest (or southwest Canada).

[joe newton]

"I just got the Allen & Mike Really Cool Backcountry Ski Book. book and it mentions doing something to generate some body heat before going to bed. They're talking about winter camping but the same thing applies in general. Warm up, go to bed warm, and your sleeping system has more to work with. Seems like pretty good advice but I'd never done it. I just try to not lose any warmth in the evening and then go to bed. Does anybody do this?"

Absolutely and I encourage friends and newbies to try this before getting into their sleeping bags. They can't believe the difference it makes. Just a couple of minutes of jumping jacks/arm swings/running on the spot really gets the blood pumping.

The other technique that I find really makes a difference is the mid-night snack of chocolate or nuts or even better – chocolate covered nuts!

[James holden]

if you want to keep warm at night

1. eat a good snack before sleeping … apparent cold is a function of nutrition … winter camping is not the time to diet … just ask the polar bears

2. go to bed warm … if you cold in yr bag do sit ups till you warm up … convert those calories into heat

3. go to bed dry … you can put yr damp clothes on top of yr bag or in a plastic bag with you in the bag to dry … have dry underwear to sleep in

4. keep yr body heat togheter …. ever play fu manchu in winter when yr cold, that is take you arms out of your sleeves and put them next to yr body … notice how its warmer, just like mitss vs gloves … do the same and dont isolate yr body parts

5. use all yr clothing … keep the driest and most insulating clothing close to you … usually thats yr down bag … layer the clothing on top of your bag or in yr bag in order of insulating properties and dampness … remember that vapor will travel outwards so that the last layers is where any moisture will likely end up … unless you're planning to dry out clothes or need to fill dead space .. why waste energy on heating up less insulating clothes

6. use yr fuel … melt and boil tmrs water before you sleep and use a nalgene as a hot water bottle

7. use a piiiss bottle … it wastes energy to warm up the piiiss if you hold it in … use a durable piiiss bottle and you have an instant hot water bottle … instant 36C warmth … recommend using a different shape bottle than yr drinking one

8. sleep with someone else … spooning works best … can be combined with #2, activities with a partner to warm you up .. bigger person should be the spooner and smaller person the spoonee to maximize coverage … spooner should also breath on spoonee so as to not waste the warmth from the lungs

lol

[John S.]

False.

"7…. it wastes energy to warm up the piiiss if you hold it in … "

[James holden]

youll find similar references all over … maybe its all an urban legend … it really doesnt take any energy to keep the water in yr bladder a body temp in winter ;)

lol

http://www.wintercampers.com/2010/07/02/sleeping-warm/

Using a Pee Bottle
Pee if you feel the urge. Holding it in requires your body to waste energy trying to heat up the water in your bladder. Getting out of your warm sleeping bag to put on boots and venturing half clothed into the snow to pee is annoying. To avoid exposing yourself to the elements use a pee bottle. If you sleep in a bivy sack a pee bottle may be a mandatory accessory.

http://www.psychovertical.com/bigsleep

A 1 litre Nalgene piiss bottle is worth it’s weight in gold on any confined bivi – and at least one British climber has died falling of a ledge going to the toilet. Clip it between both climbers so it’s handy – and don’t get it confused with the water bottle. If your cold, but feel you need to urinate, don’t hold it in all night, as your body wastes vital energy keeping this urine at body temperature.

[Mike W]

…

[Travis Leanna]

Hi Mike,
I use a KookaBay DAM, which unfortunately cannot be blown up by my breath. Since I have to use a BA Pumphouse, it fills my pad with the ambient temperature.

[Roger Caffin]

The thermal mass of the air in a pad is so small as to be entirely trivial.
But actually blowing the mat up – that tends to be a bit warming!

Cheers

[Tim Zen]

Roger,

Thermal mass!

Guess about 100 grams of air in an air pad (I will have to blow one up and measure, but good enough for the following)

The heat capacity of the air in the pad at 98 F is ~28 kilojoules, and at 20 F it is ~24 kilojoules. If you were able to extract the entire 4 kJ to keep you warm you would have enough energy to increase 1 kilogram of water 1 degree C.

Question — do we really need to use a BPA free bottle for night time use? I think this is taking leave no trace a little too far.

[Sam Farrington]

Have never had that great a variation in reponse to cold except when coming down with a bug/virus. (Assume you had had enough to eat and drink) I'll bet you picked up something that was overcome by your immune system before you got really sick, but not before you were so affected by the cold.

[Author]

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