PDA

View Full Version : Increasing Bag Warmth



Whisky
10-09-2012, 10:51 AM
Other than the obvious, buying a warmer sleeping bag, what are some options a guy can do to use a 15-20* bag in colder temps? I can only pack in so many clothes. I have a BA Mystic SL 15. It's very possible I'll be using it come Nov in ND and it will be mighty cold. I think I read somewhere about guys using a bivy sac (??) inside of the bag to increase the warmth?

What are my options and what has personally worked for you?

Thanks

smalls13
10-09-2012, 11:41 AM
A bivy sac is used on the outside to keep you dry from rain. I don't think mine would add any warmth. Most of them don't sweat either so you would be soaked if you had it inside your bag. I bought a small fleece sleeping bag that i put inside of my mummy bag if the weather is cold. It probably only adds 5 to 10 degrees though.

Chippy Hacky
10-09-2012, 12:28 PM
I add a fleece sleeping bag to mine too. It is great in cold temps but it is heavy! I found some "backpacker" fleece bags that can be used for a bag or liner, however this one was $29. I purchased it but am not impressed with it, it seems cheap and am thinking of taking it back. It says on the label that it can give you "up to" 10* (whatever that is worth).

Now, I am thinking of going to the fabric store and buying a bulk piece of fleece. I will update when I get down there but I think that I may be able to save some weight with no zippers, cords, stitching, etc.

tdub24
10-09-2012, 12:34 PM
I have a 15 degree rated bag and bought a liner which adds up to 15 degrees of warmth. So far I haven't met an environment that is too cold for this set up, and I am cold blooded. Below is a link to the liner I have.

http://www.cabelas.com/product/Sea-To-Summit-Reactor-Thermolite174-Liner/714584.uts?Ntk=AllProducts&searchPath=%2Fcatalog%2Fsearch.cmd%3Fform_state%3D searchForm%26N%3D0%26fsch%3Dtrue%26Ntk%3DAllProduc ts%26Ntt%3Dsleeping%2Bbag%2Bliner%26WTz_l%3DHeader %253BSearch-All%2BProducts&Ntt=sleeping+bag+liner&WTz_l=Header%3BSearch-All+Products

Bitterroot Bulls
10-09-2012, 12:40 PM
A bivy will certainly add warmth. The USMC GTEX bivies add noticeable warmth, in my experience.

Sawfish
10-09-2012, 01:15 PM
Big 5 has lightweight fleece sleeping bags that can be used as a liner. $19.99 regular, or $9.99 on sale at times.

Whisky
10-09-2012, 01:33 PM
Thanks for the info so far guys. That Sea to Summit liner looks to be one of the more convenient options thus far, considering packability and comfort anyways. I didn't realize them bivy sacks are that heavy.

jjenness
10-09-2012, 02:59 PM
I use a Cabela's XPG Bivy bag and it definitely ads warm to my bag. I only use it when I know the weather is going to be cold, or rainy.

Ikeepitcold
10-09-2012, 07:45 PM
A bivy will certainly add warmth. The USMC GTEX bivies add noticeable warmth, in my experience.

BB is that bivy added to the inside of the bag? Or as intended on the outside?

Bitterroot Bulls
10-09-2012, 07:48 PM
outside.

Adds warmth just like a jacket shell, more dead air space.

Not all bivys are heavy. I have a 9 ounce tiGoat bivy. It doesn't add warmth like the heavy USMC bivy, but it adds a few degrees of warmth, and acts as a groundcloth and spindrift protection in a floorless shelter.

NorthT
10-12-2012, 02:58 AM
Ditto on the cabelas xpg. I have a marmot hydrogen 30 bag. One night the temp dropped down to teens and thought i was going to freeze. Next night stuff bag inside of bivy and stayed toasty warm all night. Make sure that your bivy doesnt cover your face or it can cause condensation between the bivy and your bag.

NorthT
10-12-2012, 02:59 AM
Meant to add that I also have used the fleece liners, They work and are cheaper but feel like the bivy worked alot better for me. Mine I think is 11 oz.

ivorytip
10-12-2012, 06:52 AM
+ 1 on the tigoat. also... i have a couple of the military issued bivi sacks that work great too.

VTBwana
10-12-2012, 07:58 AM
Liners & bivies work..I alway have a few disposable hand warmers on hand; 'bombing' the bag w/hand warmers really helps and nasty cold nights. I am in the 3-172nd Mountain Infantry BN and we sleep in the cold regularily. Last winter I bombed my bag (in bivy bag, no tent) on a -12F night and was toasty while others bitched about freezing their stones off.

JMSZ
10-15-2012, 01:25 PM
I got a couple of Thinsulate poncho liners, I always have one with my bag. It's a two-part bag and rated to 30 degrees with both parts and lower with clothes on, but my feet get cold when it's in the 30s.

The poncho liner helps out a lot, the only problem is that it likes to slide around inside. On the upside, I can pull it out and use it separately when I just want to wram up and I can leave my bag part way open on cool, but not cold, nights.

Gotta try the bivy, though.

Edelweiss
10-15-2012, 02:05 PM
It is very hard to add warmth to a sleeping bag. The boyscout trick of sleeping in your underroos should always be used. Though I must admit it is hard to strip down to your skivvies to get into a sleeping bag when it's below 30 degrees. Especially if that bag is cold.

Sleeping in clothes removes that airspace and kills bag warmth.

Bitterroot Bulls
10-16-2012, 08:22 AM
Sleeping in clothes removes that airspace and kills bag warmth.

There are differing opinions on this. In my experience, I always stay warmer in the bag with extra layers on, as long as I don't have so much bulk in the bag that it starts to compress the loft of the insulation.

Whisky
10-18-2012, 10:41 AM
There are differing opinions on this. In my experience, I always stay warmer in the bag with extra layers on, as long as I don't have so much bulk in the bag that it starts to compress the loft of the insulation.

I've wondered about this.....Two different opinions on it already.

My bag is not a true mummy bag. It's the Mystic SL from BA, think they call it a rectangular bag. It seems I have plenty of air space in that bag. I did sleep in my clothes as well as layered up on the merino tops. Nothing too bulky. Although if I was to give that liner a try, that is a mummy fit.

Edelweiss
10-18-2012, 01:59 PM
There are differing opinions on this. In my experience, I always stay warmer in the bag with extra layers on, as long as I don't have so much bulk in the bag that it starts to compress the loft of the insulation.

I always freeze in a mummy bag when I am dressed, even if it's in long underwear.

Superman underoos and I am all set!

mnhunter
10-22-2012, 03:17 PM
+1 on VTBwana's reccomendation. I do the same thing and it works slick. A weeks worth of handwarmes weighs alot less than the heavier bag will.

arrowslinger21
12-16-2012, 10:04 AM
Bivy sacks add good warmth by allowing for the air around your down or other insulation to be less affected by colder air. A good sleeping pad with a high r-value helps too, like some of the great mats from exped. Other than that I would say to eat and drink hot food and fluids before bed, layer up a bit, and crawl into your bag on a good pad. Should make for a much better night.

crumy
12-19-2012, 11:31 PM
Maybe this is a bad idea since nobody else has said it, but here is what I do and I have never had a problem with being cold. I usually have a 15-20 degree bag. Based upon a recommendation from a friend I started throwing a hand warmer pack into the bottom of by bag. I don't wear any extra layers and don't wear socks so that I don't sweat in them. Does a great job. I did just upgrade to a zer degree kelty but i imagine I will keep doing it. It does make it really hard to get out of the bag in the morning because it is so warm but I like it.

arrowslinger21
01-03-2013, 10:13 PM
Maybe this is a bad idea since nobody else has said it, but here is what I do and I have never had a problem with being cold. I usually have a 15-20 degree bag. Based upon a recommendation from a friend I started throwing a hand warmer pack into the bottom of by bag. I don't wear any extra layers and don't wear socks so that I don't sweat in them. Does a great job. I did just upgrade to a zer degree kelty but i imagine I will keep doing it. It does make it really hard to get out of the bag in the morning because it is so warm but I like it.

I usually dont want to carry enough of them to rely on them every night, but it does work damn well. I sometimes carry a pack of two just in case it gets a little colder then expected for a night or two.

Bughalli
01-04-2013, 01:13 AM
I've used a bivy a number of times and love them. Most of the time its during backcountry camping and a few times during the winter. Ill throw my ground pad inside it and sleep right on the snow if needed. They add a lot of warmth because they allow the sleeping bag to further contain the body heat. Make sure it's gortex or some other breathable fabric, otherwise you will get condensation even if the head area is wide open. The bivy I use is REI's basic one. Use one of their 20% off coupons and it's something like $80. I wouldn't sleep in the rain in it on purpose, but I've done it. Most of the time i find it too warm, but its great in cold weather. For the basic one I have, there's no head covering. It's really just a sleeping bag shell. So if running into bad weather I tuck my head under a tree or rock overhang. The rest is waterproof. Sorry, getting off topic. Just saying I've used them a lot in all types of conditions.

Fleece vs bivy? This is the way I look at it. If you were cold outside would you be warmer by throwing on a fleece or a gortex shell? In my experience a shell is much much warmer. It's all about blocking the outside air and containing your own.

Clothes worn in the bag? I go back and forth on this. Not sure why but sometimes it's warmer with longjohns and other times its not. Generally bulky clothes don't work. Air in a bag is good, you just dont want it to circulate out of the bag. I will mention that blood circulation is just as important as other factors. Wearing socks, LJs or other clothes that are a little tight can make you colder than not wearing them at all. It's important to not be too constricted in a bag or any one part of your body. This doesn't happen often, but it does under the right circumstances...usually wool socks that shrunk on me in the dryer and I'm realizing it too late.

Also....it's counter intuitive, but a decent ground pad can make a difference. Thermarests are comfortable, but not great for insulating in cold weather. a foam pad is much warmer. In the winter when its in the teens or lower at night ill use both.

I've noticed the past couple hunting seasons that sleeping on a cot in a tent is colder than the ground. Having that air circulating below you on a cot has an impact when the temps drop. Just thought I would mention it since you didn't state what you sleep on.

Bughalli
01-04-2013, 01:25 AM
I had to go check since others asked about weight. The REI basic bivy is 15oz. Not too bad. I also like the fact you can zip it down a little which makes getting in and out much easier. Nothing worse than having to take a piss in the middle of the night and it takes forever to get in/out your bag during cold temps. Also the zipper is great for regulating heat. More often than not I get too hot vs cold.

Great value for the price and quality. Read the reviews for further info.
http://www.rei.com/product/794292/rei-minimalist-bivy-sack-regular

Good luck

sheephunter
01-05-2013, 04:27 PM
I get cold through the night no matter what. I think what happens is sometime in the wee hours of the morning my body just runs out of fuel and can't produce enough heat, and I start getting cold from about my knees down. Since I have to get up through the night to pee anyhow, what I have started doing is keeping my stove at the ready and when I do have to get up I quickly heat up some water (not to boiling, just warm or slightly hot to the touch) and dump it in a nalgene bottle and put it down in the bottom of my sleeping bag. If bears aren't a concern I also try to keep a little snack at the ready too. Between these 2 I can usually make it to time to get up OK.

mav_7mm
01-06-2013, 02:55 AM
+1 for the fleece liner. I have not weighed mine but when I was in Boy Scouts we would put them in our bags when snow camping. My mom made one for me that added so much warmth i only use it when it is COLD! It has become the go to present that she makes for everyone in the family. My Wife is now experimenting with making one with a pillow built in for her. I also have found the long underwear makes me a bit warmer but too many clothes does not make a noticeable difference.

Slim Pickins
01-10-2013, 07:47 PM
I like the hand warmers by my feet sometimes too. Something else that I do is a little tree trimming. I trim off a bunch of pine boughs (soft young ones) and arrange them on the ground with the arch up, cut ends outward-enough to have about 3 to 4 inches of loft. Then I pitch my one man tent over the top of them. Coupled with my waffle pad, this makes for a pretty cushy and warm mattress. What you get in the loft of the boughs is tiny pockets of air that hold heat. This might sound like a lot of work but its worth it. Credit to the 'Survivorman' for this tip.