Sleeping Bags

[Mudrat]

I'm getting ready to embark on some winter camping while going for the winter 46 in the Adirondacks. I'm looking for any and all advice on sleeping bags for the negative temperatures that are common in the mountains, especially the temperature rating on the bags. I don't know how accurate they really are. Weight is a consideration. Thanks.

 

[Johnnycakes]

I would say go for a bag with a -20 F rating. If weight is a consideration, you can't beat down. A good quality -20 F down bag will probably weigh in around 4-4.5 pounds. You can certainly get temperatures close to -40 F in the Adirondacks on the coldest of nights, but you should ask yourself if you will realistically still go camping if that kind of weather is in the forecast. Hence, my recommendation to stick with a -20 F bag. You will also reap significant weight and cost savings by going for a -20 F bag instead of a -30 F or -40 F bag.

However, if your camping trips will be greater than four nights at a time, you may want to consider going with a synthetic bag, despite the extra weight and bulk that will come with the synthetic bag. The problem with down is that condensation in the bag will accumulate with each day's use, diminishing the insulative ability of the bag each day. This is not as much of in issue during the warmer months because the condensation will evaporate during the day when the bag is not in use. Condensation does not impact the insulative ability of a synthetic bag as significantly as it does a down bag. Another alternative would be to use a vapor barrier with your down bag to prevent condensation from occuring in your down bag. See the Vapor Barrier Thread on VFTT for more information.

There are advantages to both down and synthetic bags:

Down Advantages:
-Best warmth to weight ratio available means lighter bag.
-Longevity of the fill material (20 years is not uncommon).
-Compressibility.

Down Disadvantages:
-More expensive.
-Insulative ability significantly affected by moisture in fill material.

Synthetic Advantages:
-Less expensive.
-Insulative ability not as adversely affected by moisture.

Synthetic Disadvantages:
-Shorter lifespan (5-6 years max); this is not to say that a -20 F synthetic bag is useless after 5 years, but rather that it will be more like a 0 F bag.

I'm sure others will have more good information to add here.

-John

 

[jfb]

For winter camping, I found that a bag needs to be wide enough to change clothes inside. Some bags are so narrow, I can't even change socks without zipping the bag open.

There's a pretty standard relationship between loft and temperature rating. Some of the best (but expensive) bags are made by Western Mountaineering, Feathered Friends and Integral Designs. Check out their websites for info.

 

[stoopid]

Down Disadvantages:
-More expensive.

That's an understatement. It doesn't weigh less than half the competing (quality) synthetic or provide twice the warmth, and yet somehow justifies twice the price? Even I'm not that stoopid .

I have a down 25F bag which I paid $100 for, not too bad for a bag that, with a liner, works well in 3 seasons. But the price/performance ratio goes out the window at zero and below.

 

[Warren]

I went with a Western Mountaineering puma ML. It's a -10 but WM ratings are very conservative. I'd say -20 is a good winter target rating. I had an email exchange recently on this topic, if I can condense it to a posting for this thread I will.

 

[masshysteria]

JohnnyC, I've got a question for you, or for that fact, anyone else. I have two 0 degree bags that work fine for me around here. They're both synthetic. However in the ADKs, that wouldn't be enough. If I used a fleece liner in combination with a VBL, would that keep me comfy in the -20 ranges found in the ADKs? I have a bivy bag that I use over my sleeping bag, and there is a Gore-Tex panel on the top, over my torso. The part of the sleeping bag that's covered with GT is dry in the morning. But the part of the bag covered with nylon has frost on it. Not good. Any thoughts?

 

[stoopid]

JohnnyC, I've got a question for you, or for that fact, anyone else. I have two 0 degree bags that work fine for me around here. They're both synthetic. However in the ADKs, that wouldn't be enough. If I used a fleece liner in combination with a VBL, would that keep me comfy in the -20 ranges found in the ADKs? I have a bivy bag that I use over my sleeping bag, and there is a Gore-Tex panel on the top, over my torso. The part of the sleeping bag that's covered with GT is dry in the morning. But the part of the bag covered with nylon has frost on it. Not good. Any thoughts?

From my understanding you get about 10F from a liner, no matter how good the liner. Any thicker/more efficient you start losing some of the bag's insulating benefit. The goretex shell/bivy is a good idea, at least when it works. Unfortunately they don't make the whole bivy out of the stuff! You should get another 10+F from the bivy, so liner and bivy may get you -20F.

I'm going to subscribe to the thread to find out what to do about the condensation.

 

[Neil]

Another alternative would be to use a vapor barrier with your down bag to prevent condensation from occuring in your down bag. See the Vapor Barrier Thread on VFTT for more information.

Down Advantages:
-Best warmth to weight ratio available means lighter bag.
-Longevity of the fill material (20 years is not uncommon).
-Compressibility.
-John

I stuck a vapor barrier in my down bag and it works wonders. Kinda like crawling into a condom though. My bag is almost 30 yrs old and was rated to -40. I'd say its good to -25 now. Before using the VBL if it was sunny I'd leave it in the sun (it's dark blue), go off on a day hike and it would be ice free when I got back. This with a high temp of -10F. When I start over I'll go with Johnnycakes' advice re: a -20F rated bag and get a liner and/or bivvy overbag. If the forecast was for -20F I would want to be armed with more than a -20F bag.

Stoopid notes the high cost of down but my aging bag is still quite serviceable 28 yrs. later.

 

[Rick]

Stoopid notes the high cost of down but my aging bag is still quite serviceable 28 yrs. later.

Ditto, 1982 EMS Robson Long -30d down bag is still smoking 22 years later!!!
Down with a VBL is definitely the way to go, especially when you amortize the cost over 15-20 years compared to buying 2-3 synth bags (unless you don't plan to be winter camping for more than a few years)

 

[Warren]

Clipped out of a series of emails, reiterates some of the above, sorry about the length:

Generally the wisdom for a larger winter bag is to put your boots in the toe. If you have double boots this is likely less important as they and your water are about all thats in danger of freezing [and plastics don't freeze]. I regret getting the larger Puma, it doesn't fit as well in the bivy or in a tent.

Oh, and make sure any "big" bag fits your pack.

It's good, but a dryloft bag is not waterproof by any means. I much prefer a dryloft bivy (OR makes one, there are epic based one, OR's bivy may now be made of windshear about $80). A down bag should have the most breathable shell possible so your sweat can escape and when damp the bag can dry. The only thing I'd like to see is dry loft around the hood since in winter your breath freezes and drops back down on you where the warmth from your breath melts it making the area around the hood opening somewhat damp. The DryLoft puma bag I briefly had was very difficult to compress (though may have worked better inside out, it retained a lot of air).

The question is what is a winter bag for your purpose? If you're doing long trips (4 days+) synthetic makes a lot of sense, shorter trips down rules. In the NE I figure -10 to -20 is a good winter bag temp. Anything more will likely be overkill. Figure in the winter you'll be camping out in Huts often and camping low in protected areas. If the weather is predicting -60 temps I bet you'll stay home. If you aspire to denali, I would get a bag for denali then, not now.

If my bag is down in the winter my jacket is synthetic.

My feeling on this: get the shortest, tightest fitting bag you can handle.

Though at the last winter gathering on Friday night I stayed in the puma in a tent just me and was very warm. Temps? I think it was -35.

I have a synthetic liner (add 5°), goretex bivy (add 10°), dryloft bivy (add 10°) and a vapor barrier that's never been used. With some clothes on I can push the Puma to -30°.

I recently read about this . Interesting, I wonder if it would combine well with a bag, would at least be a decent emergency bag (though that's usually what I carry the VBL for).

 

[spaddock]

Last year I was out below Upper WolfJaw and the temperatures were about -10F. I had a +20F down bag, with an overbag. I also wore some clothes with a toque and was pretty toasty.

I'm considering going with a VBL or a fleece liner this year if it dips down much lower than that.


-Shayne

 

[JackH]

down bags

I have to agree on the durability of down bags. I have a +10 bag I bought from EMS in 1979 and can push it comfortably to zero with a fleece liner. Although the bag may have lost a few degrees over the years it has only failed me in really damp, multi day trips. I found that reducing the open space in the bag by filling with fleece or dry clothes can really help in marginal situations. Now, I really want a minus 20 for winter hikes and have to begin my research. Any suggestions about the newer features in down bags?