Sleeping bag insulation

OK, paddlers… A while back you helped me fit my bulky sleeping bag in my skinny VCP kayak hatches. But I was too cold that night with ice on the tent in the morning. Time to kick it down a few degrees to a 0-degree bag.

There is down, then everything synthetic. Down is expensive, lasts a long time and compresses and insulates well. It sucks when wet.

Good synthetics bags are cheaper, and insulate when wet. They are also heavy, bulky, big and lose loft and insulation value as the fibers degrade over time.

So, I would love down in a dry bag. Small package, lighter and warm.

However, if poop happens, and it gets wet…it’s gonna be a long cold night.

I hear good things about certain synthetics and list these in order of greatness… then a few I am not sure what they really are:


Polargard HV

Polargard 3D



all the other -fills

There are many bags with “private label” fills that I am not sure what they really are




what ever Wiggy’s uses

So here is/are the questions… Who uses a down bag for cold weather camping and why?

For you others, what is the insulation in your bag for cold weather camping that you can reccomend? I cannot find too many with primaloft and many companies make it difficult to identify the insulation material. Thanks in advance.

How big
is the hatch on your Yak? I have a bag rated to 5 degress Fahrehiet and a compression sak that makes it the size of a slightly elongated basketball. Or you can get a bag linner so you are stowing two parts of your sleeping bag instead of one big mass.

Thermolite or Thinsulate

– Last Updated: Feb-22-06 5:22 PM EST –

Thinsulate is the best, and is remarkably for the issue of breakdown of the fibers, compress the bag only while in use, store it hanging up or in a LARGE loose fitting cotton bag, and that becomes a non-issue.

Get a sleeping bag cover (Nylon) or a bivy sack (Goretex) to add insulation value and protect the bag from dirt and debris.

Do a web search for Woods Sleeping bags (Canadian company with dealers in the US).

VCP oval hatches
I managed to get the bulky bag in the VCP hatch. My prior boat had a hatch big enough for a opera singer to sit in.

sleeping bag insulation
i have a wiggy’s ultralite and can unequivocably give it a thumbs up. the synthetic insulation is laminated to the bag, eliminating shifting of insulation. i can personally testify that it will keep one warm even when wet in temps in the mid 30’s F. it is well made, easy to care for, is decently compressible, and the guarantee is unbeatable. the only other synthetic insulation i would consider is polarguard. it is a proven perfomer. beware claims of thin materials being able to outperform standard lofting insulations as the dead air space is what provides the warm micro-climate by holding in your body heat and slowing conduction heat loss. my 2 cents. -harry

Big Agnes

Big Agnes
makes a mix of down and synthetic if you want to split the difference.

The sleeve for your sleeping pad is an amazing plus.


thinsulate? not even in the running.
Thinsulate is a tradename for a whole family of fibrefill insulations with differing attributes and they have done an incredible job of branding them as if they were one. Thinsulate, ‘Liteloft’ was popular for sleeping bags for quite a while but has since been surpassed by many different and superior insulations. you are most likely to see Thinsulate in some types of footwear now, because it is heavy, durable and cheap.

there are many many fiber fill insulations and yes they are hard to all figure out. ultimately you go with the overall bag design, fill considerations and price but this may help:

manufacturers use many different methods for achieving difference performance. ‘performance’ is defined across a broad spectrum of competing attributes such as, thermal efficiency, weight, compressibility, wash stability, long term durability, and number one to the manufacturer of course, cost!

they achieve this by spinning fibres out of polyester then putting them together in ‘batts’ in many different forms, so it is practical to add to clothing, bags, etc. the fibres range from short staples to very long continuous filaments which may receive ‘treatments’ such as silicone to enhance water resistance, and they are held together in these batts by resins or by heat which melts the fibres in certain places. the coarser the fibres and the more resin used makes for a more durable, wash stable insulation, which is also heavier, less compressible, and does not conform to your bodys contours as well. you see where this is going right? as with everything, it’s a compromise to make the ‘best’ insulation.

down happens to be the ‘best’ in that it is the most thermally efficient, lightest, loftiest, and contours to your body best, also just happens to be highly durable! imagine all that! the genius of nature. but it isn’t the ‘best’ if it gets wet of course.

Primaloft (and there are a handful of them in this family of which different aspects are maximized for the specific end use) has been for a few years now, the most ‘down like’ in performance (read: lightest, warmest, most compressible) and holds up well when wet, but it is not the most wash stable. maybe it has improved over time, it’s marketing certainly has. it is also quite expensive.

Polargaurd 3D is, i think, their latest offering, which is supposed to be an improvement over HV and i’m sure it is. this is a very good insulation, but it is my understanding that it doesn’t compare favourably to Primaloft in terms of weight to warmth ratio or compressibility. it is likely more durable and wash stable.

measuring thermal efficiency gets truly esoteric very quickly. CLO units which are a measure of warmth are just too difficult and boring to explain here but i’m sure the genie in the box can help if you want that kind of depth…it’s like getting into ‘denier’ to understand fabrics…

there are many good synthetics out there, but until i learn differently, for my money, i’m looking at a Primaloft bag for the closest to down’s best attributes along with some dampness security.

cheers, and warm sleeping.

Down all the way
I’ve got both but always trip anymore with down. It is lighter, packs smaller, has a broader comfort range and will live longer. I don’t care what anyone says but synthetics suck royal when wet also. Using a tent I’ve never had a wet bag anyway, so after 40+ years of camping my bag only got wet once, while hitchhiking w/o a tent. It SUCKED. And it WAS synthetic. Be careful, use a good sealed tent, and the down will always feel more comfortable to sleep in in the long run. And I’m going to recommend ‘Western Mountaineering’ as the best made down bags on the market. Trust me… you will not find a finer series of bags on the planet.

Western Mountaineering=Awesome!


Like Stickman…
…I come fromm a humid climate but still prefer down. I’ve been on week long trips in the BWCAW when it’s rained every day and it’s gotten a bit damp, but never damp enough to be an issue. Another thing about down is that if taken care of, it can last a lifetime. I bought a North Face Superlight when I was 17, I’m 45 now and the only problem with it is my body doesn’t fit a slim, tapered mummy bag anymore! WW

Down again…
I think down has a worse reputation when wet than it deserves. It may be good marketing on the part of the synthetics manufacturers… That said, don’t let any bag get wet, of course.

I’ve got 3 down bags–2 for kayaking and 1 for cold mountaineering/hunting. The warmest is a -30F rated custom made by Feathered Friends using a gore-tex like (but more breathable) shell. All of them have breathable water-resistant shell material, which so far in my experience seems to be good in combination with down, even for kayaking. These bags, even the big one (800+ fill helps) fit nicely in VCP hatches. The smaller two at +15F rating could fit through my day hatch without a compression stuffsack. You might look at Feathered Friends, Western Mountaineering (not 100% sure they have water-resistant/breathable shells, but they probalbly do), North Face and Marmot for some of the best bags available with this combination of shell and down.

In super cold temps and many nights of use of a bag, insulation of any kind will start to lose loft and gain weight as water vapor from your body freezes in it before it can escape the bag. In these conditions, folks will often sleep in a non-breathable ‘body bag’ that captures all the water vapor your body puts out. This saves the insulation at the price of sleeping/swimming in your own body moisture, which can be a significant amount over the course of a night. Sounds fun, huh? Not sure if you’re to this point, but it may be a point of information.

Part of the system, as you probably know, is to protect the bag from getting wet and that means a watertight tent or bivvy system that breathes well. Double wall (tent and rainfly) or single wall (i.e. Bibler tents–many single walls don’t do a good job of keeping you dry), it doesn’t matter as long as it keeps you dry and well ventilated. Bibler’s ToddTex material has done a great job for me. I often find the inside of the tent drier in it after a night (no condensation) than in high quality double wall tents. As a shamelss plug for what I think is a decent/handle almost any condition kayaking tent is the Marmot Swallow. It’s very convertible from almost all netting in the tent body for breathability to a 4-season, all condition tent. It seems very well made as well.

Good luck!

Another downer
I will NEVER part with my down bag. I can compress it small enough to fit in a very small hatch, and I leave it hanging up the rest of the time. I’ve only had it wet once, and it was still warm. It is warm when it’s cold, yet I don’t get overheated when it’s warm.

Pretty much agree
But no single walled tents in extreem wet climates. Own a Bibler and used it at high altitude. Great for that…sucks in PNW rain storms. Double wall all the way, and I even put a tarp up and pitch the tent under it.

Down is the only choice for me. I sometimes use a very thin synthetic overbag. Worst case, which in over 20 years in PNW and SE Alaska has not happened to me, bag gets wet. Not gonna die. But I’ve had an old fart from the SE call me dangerous on this forum for using down :slight_smile:

I’ll stay dangerous.

You guys are all dangerous man!!
How can you recommend down…that’s careless! Oh my…people are gonna die…:slight_smile:

check out this

The best

Bibler Torre. With double vestibule allowing more through ventilation and a couple of built in vents and breathable Toddtex, I was able to keep it fairly dry in rain. It may do better in wet conditions than some of the other Biblers? I don’t know. Overall, more of a mountaineering tent for sure which is it’s primary use for me.

One thing I like about that Marmot Swallow is the pole sleeves are built out of netting allowing for better air flow between the two walls of the tent–pretty standard now days on many tents I think. Not quite as warm in very cold windy conditions as ‘solid’ fabric pole sleeves that will inhibit air flow to a greater degree.

Not even close!

Down here
I have and use both but when light weight, size and comfort matter most I choose down.

2nd Vote For Wiggy
They are far from the lightest bags but are arguably the strongest and longest lasting synthetic bag.

The wilderness program I work for uses Wiggys exclusively. We have tried a number of other bags but their lifespan has always ended up to be half that of a Wiggys.

I have the double bag system that gives a comfort range from 0-summer.