[sparky]

a few years ago my life was transformed when I we did the AT. I realized the value of ultra light backpacking! this has influenced me in boating and back country outings. I usually do one or two extreme trips a winter where I will go up to around 12,000 to 13,000 feet and camp when it is below freezing using a bivy sack. (i try to find some shelter in rock outcrops or snow to add to the protection.

so here is my dilemma. not wanting to take too much weight, yet not freeze my ***** off.

I am trying to find out if there is any research on temp ratings for doubling up sleeping bags. I am trying to find a lighter weight system.

I have been using a zero degree bag for a while in a bivy sack, but was wondering if doubling up on two 35 degree bags would do better. ( last time I did this it was -20 with out windchill. froze my butt off but no harm was done to any other appendages)

what are your thoughts. I am really, really limited on finances. so buying new gear is kinda our of the question. (because if i could i would want to buy a Arc Expedition quilt)

so thanks for any feedback!
also i am trying to make a light weight sil tepee tent for added protection any recommendations on that would also be great!

 

[glenn]

I think layer up on bags is bad, I think it has to do with how the bags insulate, but I'm far from an expert. There are sleeves which pack down to the size of a poncho which claim to add about 10degrees of warmth to your bag. I think you can double up on those. They come in silk and a synthetic. Reasonably priced, that may be your best option.

 

[Redpaddle]

I have to second glenn here and say that I think layering bags isn't a good option. While I think they would definitely add insulation I think the compression of the loft you would get by layering would reduce their insulation but also, my experience has been that the relationship of insulation to temperature probably isn't linear i.e. if you want to get a zero degree bag, you can't add two 30 degree bags together, then to get a -30 deg bag you just need one more 30 degree bag! Some braniac engineer out there can explain it better I'm sure.

also, sleeping in a bivy in these conditions is rough (as you found out!) a tent will give you a pocket of air to warm up a bit more, if you can get it set up.

Have slept in quinzees a few times and they definitely beat a tent or bivy if you have the time to make them (but solo I probably wouldn't try). Also if you're climbing to 13,000 feet though, you will be plumb exhausted trying to make one.

I have not been impressed with the bag liners, they don't do much for me. a hot water bottle in your bag helps a bunch though.

My best suggestion would be to try out some combinations in more tame environments (camping closer to your car and/or with other people) before you head out to the high country. A warm snuggle bunny is always a good option too, and free!

good luck and stay warm!

 

[Theophilus]

You might try adding an Army poncho liner to your bag. I've spent a zillion nights under the stars in Alaska with an extreme cold weather bag and a poncho liner. Gets too cold you can throw in a hand warmer.

I have the Wiggy's FTRSS made in Grand Junction. It's a two bag system. Give them a call and they'll tell you everything you need to know about two bag systems. Especially if you speak to Wiggy himself

 

[Airborne2504]

I definately 2nd what THEO says.

You might try adding an Army poncho liner to your bag. I've spent a zillion nights under the stars in Alaska with an extreme cold weather bag and a poncho liner. Gets too cold you can throw in a hand warmer.

I have the Wiggy's FTRSS made in Grand Junction. It's a two bag system. Give them a call and they'll tell you everything you need to know about two bag systems. Especially if you speak to Wiggy himself

AND, to give you another option, check this one modular sleep system out. I'ved used this in freezing temps and snowy weather in the mountains of Afshittystan. It's solid.
Buy Military Modular Sleeping Bags at Army Surplus World

Army Poncho Liner (AKA, "Wooby") that THEO mentioned:
Buy G I Camo Poncho Liner at Army Surplus World

AND, here's the Wiggy's that Theo mentioned:
Sleeping Bags

Stay Warm!

 

[Airborne2504]

USED GEAR; Local Shop here in Colorado Springs

Glenn's Army Surplus here in the Springs is full of used gear (A LOT of it BARELY used, and in near new condition) for GREAT prices.

They just recently got their online store up and running;
Glenn's Army Surplus Home

They have A LOT more in their actual store front location, so, if you don't see what you're lookin for in their online store, give them a call, and/or Maybe make the drive down to check them out:

114 E. Mill Street
Colorado Springs, CO 80903

Phone #: 719-634-9828

 

[Randaddy]

Sleeping bag liners work and are much lighter than a second bag. Do you own a zero degree bag? I'm not sure why you would want to carry two sleeping bags, unless you already have them and can't spend any money, which I can totally relate to. If you own a zero bag you should consider wearing fleece pants and a down jacket when you sleep inside the bag. (Anyone who subscribes to the theory that less clothing in the bag is warmer is WRONG - please refer to the lawas of thermodynamics before commenting on this. It's bullshit propaganda put out by sleeping bag companies!)

If you are looking for a quality sleeping bag, I work for GoLite and we have two sales in Denver right now, selling 2010 bags at almost half price. We can put you in a zero degree, 800 fill down bag that's under four pounds for under $300... Feel free to PM me for details.

 

[glenn]

(Anyone who subscribes to the theory that less clothing in the bag is warmer is WRONG - please refer to the lawas of thermodynamics before commenting on this. It's bullshit propaganda put out by sleeping bag companies!)

Obviously insulating warm layers are good, but I was under the understanding that shells just add bulk and disallow warmth from being reflected back to you from the bag. You tell me, I've never been so cold that I would try. I can't imagine a comfortable way for me to fit my shells inside my mummies either.

 

[Randaddy]

Obviously insulating warm layers are good, but I was under the understanding that shells just add bulk and disallow warmth from being reflected back to you from the bag. You tell me, I've never been so cold that I would try. I can't imagine a comfortable way for me to fit my shells inside my mummies either.

When you wear clothing inside the bag you keep more heat from ever escaping your body - even in a tight mummy bag there is usually some air space that steals heat from you.

I know people that design sleeping bags for a couple of major manufacturers and they both subscribe to the "heat reflects back" theory. I just don't get it. More layers will equal more warmth. Think of the down jacket as just more sleeping bag. Less heat leaves your body and your body stays warmer. I have tested this on consecutive 0 degree nights in a quincy and reported much more warmth with my clothing on.

It's funny how gear geeks perpetuate these rumors founded in bad science.

 

[Theophilus]

I'm not sure why you would want to carry two sleeping bags, unless you already have them and can't spend any money, which I can totally relate to.

Modularity allows flexibility through all seasons. Why carry more bag than nessesarry or less bag than required?

 

[Theophilus]

Sparky

The poncho liner is essentially a quilted rectangular bag liner that is much more versatile. Combined with a poncho it makes a great ultra light summer sleep system. I'd say stick a poncho liner in your zero degree bag and try it out. I'll bet you gain 10 more degrees with it.

 

[sparky]

SO my theory is that you want to trap air in, while allowing perspiration to leave. (I am not a big fan of vapor barriers for sleeping systems) I have several bags that I have accumulated over the years. my zero degree bag is a brute! I am trying to do some long distance hiking in "fun" conditions and trying to reduce the weight as much as possible. in that trying to multi-function my gear!
I always take a camp Jacket, usually a 800 fill down moonstone, and fleece bibs to sleep in. I also have an exped dreamwalker sleeping bag that doubles a a very warm vest at camp! I have been using it for a liner in really cold conditions. My reason to try to double up on the bag is to create more air entrapment with less bulk. that was my thinking on using two lighter bags. both my summer bags would weigh in at around 2 to 2.5 pounds and compress a lot more than my zero bag.

Randaddy, dude Golite makes some amazing gear. I just got a golite caddy Synthetic jacket and it is awesome. it is a little heavier with all the zippers but I love that you don't have to take it off when hiking because of the great ventilation. I just wish it had a hood and thumb holes in the sleeves to retain more heat.

I am going to look into the poncho liner. see if that will make any difference.

I have to admit it becomes addicting when you start to cut weight out of a pack. it is a very freeing thing, but expensive with all the cool gear out there.

 

[watermonkey]

I have to second glenn here and say that I think layering bags isn't a good option. While I think they would definitely add insulation I think the compression of the loft you would get by layering would reduce their insulation but also, my experience has been that the relationship of insulation to temperature probably isn't linear i.e. if you want to get a zero degree bag, you can't add two 30 degree bags together, then to get a -30 deg bag you just need one more 30 degree bag! Some braniac engineer out there can explain it better I'm sure.

also, sleeping in a bivy in these conditions is rough (as you found out!) a tent will give you a pocket of air to warm up a bit more, if you can get it set up.

Have slept in quinzees a few times and they definitely beat a tent or bivy if you have the time to make them (but solo I probably wouldn't try). Also if you're climbing to 13,000 feet though, you will be plumb exhausted trying to make one.

I have not been impressed with the bag liners, they don't do much for me. a hot water bottle in your bag helps a bunch though.

My best suggestion would be to try out some combinations in more tame environments (camping closer to your car and/or with other people) before you head out to the high country. A warm snuggle bunny is always a good option too, and free!

good luck and stay warm!

A warm snuggle bunny IS always a good option, but they tend to be the most expensive/maintenance intensive pieces of gear.

 

[Redpaddle]

yeah, good point, maybe just get two cheap ones and layer them on top of you then

 

[Theophilus]

The last couple of paragraphs of this page explain the theories About Us

 

[catwoman]

I have a 15 and a 25 degree bag, one shorter, one longer. When I am winter camping I often take both. They have served me well for many years, and pack down to nothing. On a mountaineering trip years ago a friend said, "If you aren't wearing all your DRY clothes at night, you brought too many clothes".