I am trying to think of lightweight ideas to provide warmth while sleeping that do not involve any sort of high lofting insulation like down or Primaloft. Fleece is always an option but not a light one. I believe a good bivy sack will help out with about 10 degrees and a sleeping bag liner will do for about 3-5 but what else is there and how much will they help you out for? Thanks.

A vapour barrier. Most people say its only tolarable in freezing weather though- what temps are you looking at?

Anything from 20-80F

Brett,

To help answer your question, could you explain why you don't want to go with high loft insulation?

Wouldn't 3 to 5 oz of insulation more in your sleeping bag be warmer than simply carrying a 3-5oz liner? (I have a coccoon liner that I have used to add warth to a bag, but no longer using it, having bought 850 down fill bag that is 15 degree at 2lb 3 oz.).

Anyway, to add my thoughts to your question, I would think light weight therma tops and bottoms would help out.

I recently purchased BPL's Merino wool long johns & long sleeve shirt to help me increase the warmth of my 40 degree Marmot Atom bag, but I have yet to try out this combination.

Sleeping with a fleece hat will help.

I have slept with my windshirt on to add warmth, but I do find that since it does not breath well, it can get a little humid/uncomfortable.

For me, the biggest enhancement has been laying my jacket across my chest like a blanket inside my sleeping bag to capture more warmth. In my case, I have a Montbell Thermawrap Jacket.

Hope this helps.

How about Evazote foam from Gossamer Gear?

http://www.gossamergear.com/cgi-bin/gossamergear/thinlight.html

Insulation is about more than loft. .375" of Evazote will provide much more insulation than .375" of down.

I am going to use my clothes in the sleep system which does include some tights (pat cap 2) and a long sleeve shirt (pat r.5) and a Momentum windshirt. I will also have a few pairs of liner socks and a fleece balaclava and hat along in addition to some Seirus All Weather gloves.

I would just like some piece of somewhat windproof non-high loft insulation to throw over me while I sleep when the need arises.

As for your question, I will not be having a sleeping bag or quilt. The temps will probably go down to 40F but I would like there to be room to go down to 20F in case of an emergency.

I have been thinking about making a Tyvek or Momentum sack bivy and maybe use that in conjunction with my AMK emergency bivy and a 9' piece of noseeum but I would like something more insulative. I just wish that there was a nice sightly insulating fabric you could buy off the shelf that is not bulky or heavy and pretty windproof

As for the Gossamer Gear stuff, I already have the 3/4 length pad in that. I am trying to get use to sleeping on my side in that but not having so much luck so far.

If I can find how to get that to work with my side sleeping, that would be great but bulky.

Am I reading this right - you are not using anything like a sleeping bag or quilt and expecting to sleep out to at least 40 degrees and hope to go lower???

You would need quite a bit of layers of clothing to do that with any level of comfort, likely including thick insulated pants and jacket as well as additional base layers. Maybe a heavy fur coat and leggings might work, but that would be a lot bulkier than a sleeping bag or high loft clothing.

Or you could take a woodstove...

Edited by RiverRunner on 07/14/2008 09:20:27 MDT.

I have slept to the mid 50s naked in an emergency bivy before just to see if I could except that the bivy starts to smell after a few days. I have sat around with no activity in the upper 40s with a wicking t and an R.5 with cap 2 leggings and pants on in additon to gloves, 2 pairs liner socks and the balaclava and been fine for hours so I don't see it as a stretch.

That is why if I could find a lightly insulated, semi windproof, breathable material to use as a blanket I think I will be fine.

Look at the Nunatak Arc Edge, rated to 40F and only has 6 oz of down. Look at the Montbell Thermal Sheet, rated to 50F and only 4.5 ounces of down. I think I will be wearing enough clothes to comepnsate and have a windbreak in the form of tarp/poncho. I just need something to keep the heat in a bit.

Or maybe I am just crazy. Still doesn't mean I shouldn't try it though.

Edited by bpeugh on 07/10/2008 13:01:40 MDT.

A reflective VBL will help a lot. Maybe a Heat Sheets emergency bivy?

I already have the old Thermo-lite bivy by AMK but I will take a look at the emergency one.

Two or three years ago I got this cool, bizarre emergency bivy bag. It's made by MPI, think it's called the extreme tech or something. It's an aluminum/aluminized emergency blanket--but corrugated. Yep, that's right--corrugated. It's basically an emergency blanket shell, emergency blanket "inner," and emergency blanket corrugation. It comes in a small pack, and will never, ever, ever get near that size again. The cool thing about it, though, is that it's ridiculously warm. I've slept in it in just a light longie layer in 20 degree nights and been toasty. Tent partners are not fond of the potato chip bag crunching all night. I don't remember how much it weighs, either--bah! Just thought it'd be an interesting tidbit to share.

Is it this?

http://www.mpioutdoors.com/product2.shtml

You could consider this one also:
http://www.adventuremedicalkits.com/kit_detail.asp?kitNO=0140-0701

And there is an option to sew bivysack from reflective Silnylon.

Before I owned any high loft clothing, I was wrapping a piece of mylar needled fleece around me for warmth. It reflects heat well, can be worn as a very comfortable kilt, and makes a fine piece of insulation inside my hammock.

I think my piece is 48"W X 96" long, weighs 11.9oz,and packs down to the size of a football.

Nice, Cameron! What is mylar needled fleece? I haven't heard of it before....

I'm pretty sure it's the natural result of a strange love triangle involving a silver space blanket, a roll of hollow-fiber polyester fleece, and an angry jealous needle.

It appears to be a silver space blanket like material, bonded to a sheet of 1/8" fleece, and then micro-perforated in a way that pulls a small amount of the polyester through the sheet of space blanket like material, leaving most of the fleece on the other side.

I found it at a very large Long's drugstore in Oakland CA.

Edited by redmonk on 07/11/2008 20:35:22 MDT.

I could not be more confused? What is the purpose of this? Is there any weight savings here or do you just have some strange fear of lofting insulation? I'm not trying to be a smart @55, but I really don't know what is being accomplished. It seems that with a single layer of insulating clothing and a very light quilt you would be warmer with less hassle and weight. What am I missing?

That is cool, Cameron! I've never heard of Mylar Needle Fleece either. What temps did you use it in? Do you know if the store you got it from still carries it?

Brett,
There is a reason high lofting insulation is so popular. It is the lightest, least bulky way to carry warmth. 3-5 ounces of polyester or wool clothing is not equivalent to 3-5 ounces of high lofting down. No, just no. Nor is it anywhere near equivalent to the warmth of 3-5 ounces of high loft synthetic insulation. That's why people carry sleeping bags that are filled with these high lofting materials. They're warmer for the weight. Even if you brought enough clothes to wear and sleep in, you'd always be bringing more weight going the clothing route.

Is there a reason to avoid high lofting insulation?