warmer when wet, one more time?

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warmer when wet, one more time?

#1

Post by BillyBob66 » Wed Mar 16, 2016 9:54 am

In the endless debate over whether there is any advantage to synthetic over down when there is any chance your gear will get wet(from outside rain/snow or from inside sweat/condensation), I have stumbled on another test, even if not very scientific. But even more interesting, it is comparing synthetic to treated down.

I have posted previously about my testing of a very wet Polarguard jacket over in a recent thread here about the feasibility of a DIY cotton UQ. But I have also stated the opinion more than once that any advantages– if they exist(and I felt they did) of synthetic in wet conditions was now moot with the advent of treated down. It seemed to me that treated down would at least equal synthetic in wet conditions, and maybe even be superior to it. But maybe not.

In this testing, it appears there is still an advantage to synthetic installations in wet conditions. Keep in mind, this test is not very scientific at all IMO, but it might still give us some useful information. The most surprising part to me is that even though the treated down dried much quicker than the synthetic, regardless, the tester felt that the synthetic "kept me by far the warmest when it was wet". And though it was the heaviest bag in the test, that only amounted to 3 ounces extra weight. No doubt, it was also much bulkier, so I'm sure there is still a very large advantage to down when pack volume is at a premium.

I noticed in the comments that, despite the results of this test, people were still chiming in with things like "everyone who says you can sleep in a synthetic bag even if it gets wet has obviously never slept in a wet synthetic bag before ". I think the point is that there is an advantage, not that anyone could ever choose to sleep in a wet bag(except maybe for testing) if they could sleep in a dry bag. In this test– as far as I can tell–the tester still(maybe?) became uncomfortable, it's just that it took twice as long. Or maybe not, maybe they just cut to test off at 47 minutes once they had a clear winner? There are not many details provided. But since they say things like"by far the warmest" and "the material touching my skin felt warm at around the 15-minute mark.", maybe they didn't try to actually sleep in the bag, and just ended the test at 47 minutes–once they had a clear winner–even though they were still reasonably warm? But of course I don't know, I'm just guessing. But at an absolute minimum they were able to stay in the synthetic bag twice as long as in the treated down bag. And that is TREATED down. Imagine had the test just been comparing synthetc to traditional down.

I also found it very interesting that even though the synthetic bag was judged significantly warmer when wet, that it took it several hours longer to dry. I assume these bags are all roughly the same temperature rating, and they are within 3 ounces of the same weight. But that leaves me wondering what they did to dry the bags? Considering that in my testing of a very light but wet Polarguard jacket, walking fast around the neighborhood in light precipitation at about freezing, it was bone dry in 30 minutes except for some small areas at the very end of the sleeves. Of course you wouldn't be exercising inside the sleeping bag, though you can add a hot water bottle plus do sit ups while snacking intermittently on a high-fat food(I speak from personal experience) to generate body heat and help dry the bag. But it took all of these bags 5+ hours to dry, and eight+ hours for the synthetic. But who knows under what conditions.

Anyway, here is some more fun food for thought. It seems to me to confirm more or less, that synthetic insulation is warmer when wet. I will be interested in folk's thoughts!

http://www.outsideonline.com/1786146/wh ... eeping-bag
Last edited by BillyBob66 on Wed May 11, 2016 9:35 pm, edited 1 time in total.


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Re: warmer when wet, one more time?

#2

Post by Idaho Hanger » Mon Mar 28, 2016 6:48 pm

There's a lot of questions about that article for sure, but it seems to verify the popular opinion that synthetics are better when wet. My unscientific opinion is that wet down collapses completely, making it virtually useless. By their nature, synthetics are less compressible which would lead one to believe that even saturated with water they would still be able to trap air to some extent because the synthetic fibers still have some structure. That's kind of the advantage to wool in wet conditions. It doesn't collapse when wet so it can still trap air. I'm at a loss as to why the drying time would be so much longer unless the weight of the shell material is playing a part.

I still use down for everything unless I'm expecting high humidity or a lot of rain but that's not a common scenario where I hike. Most ultralight gear comes with a durability trade off; I think the cost and issues with moisture that down has are just the trade off for the weight and volume advantages. The other big advantage of down that is often overlooked is its superior breathability. A synthetic bag rated at 30 will cook you at 60 degrees. I feel like the comfort range on a down bag is much wider than a synthetic, making that one piece of gear more useful in more conditions.
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Re: warmer when wet, one more time?

#3

Post by BillyBob66 » Mon Mar 28, 2016 8:36 pm

Hey Idaho, thx for the response! I thought this thread must simply have bored everyone to death, not worth a response! ;)

But the part that caught my attention- that despite the much longer drying time you mentioned- that the syn was still warmer than even the treated down. If they had shown a big advantage over regular down, I would not have been surprised at all just based on my personal experience plus everything I have ever read. But I was really hoping that treated down had completely closed that gap, leaving only the known advantages of down.

The other thing about these results, assuming they are accurate at all: If the synthetic indeed took that long to dry(in my experience, the synthetics I have used dried very quickly) that must mean that it was wetter during the test period than the down bags. If that is so(I'm not sure it is) then logically that would mean the syn was warmer while still wetter. Or warmer than the dry or at least significantly drier treated down. And presumably, all of this performance advantage of the syn over treated down would be magnified compared to regular down.

I have a dridown TQ, but I have never put it too the test when wet as I have my synthetic clothing.

And speaking of syn drying quicker in my experience, today I wore a very thin synthetic top while taking my Grandsons hiking using map and compass to go straight through the woods off trail, to an abandoned cemetery at a deserted community, with a lot of up and down. It was cold and windy to start, but warmed up a lot for later in the hike and we were really pushing it. I really worked up a sweat and soaked that top. By the time I got home(20 minute drive) it was bone dry. When I do that in cotton(don't know about down) it is wet or damp for hours.
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Re: warmer when wet, one more time?

#4

Post by Idaho Hanger » Tue Mar 29, 2016 1:48 pm

Down dries very slowly. If you've ever washed a down sleeping bag think about the time it took tumbling in the dryer to dry out. Mine took 4 hours last time. Apparently treated down dries faster but it still takes a long time. I personally like polar fleece for jackets in the cold. If I sweat I can dry it. With down it will be damp for a long time.
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Re: warmer when wet, one more time?

#5

Post by pofloyd1 » Wed Mar 30, 2016 9:09 am

Here in Indiana I only use synthetic because it is always a damp cold here. One time years ago I brought my wife a nice rain proof down jacket and she would be cold if we were out for 4 or more hours. We were out one time and got caught in a downpour 15 minutes from our car. In a very short time I traded her jackets because hers was so wet it was useless. The next day she got a new synthetic jacket. And I got out of the doghouse. ;)

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Re: warmer when wet, one more time?

#6

Post by Mophead » Mon May 09, 2016 8:41 pm

I hear the whole "synthetic is warmer when wet" mostly from sales people and "survivalists". This kind of makes me skeptical of it out of the gate. When I was thinking over and testing the necessity of a coozie freezer bag cooking that sarge did his video on, I was reading some stuff that is pertinent to this. Two people did tests with wet wool, one on a bowl of heated water and another using himself. Measured at regular intervals using dry wool, wet wool, wet cotton, and nothing at all.

Here is the one with the bowl:
http://woodtrekker.blogspot.com/2012/03 ... n-wet.html

Here is the self ginea pig one"
http://stuffadamdid.blogspot.com/2015/0 ... l-and.html

I know I have personally always heard that "wool retains 80% of its warmth when wet." And I took this for granted, based on the idea that wool is more structural and wicks better. Both tests showed, however, that you are colder with wet wool than you would be with nothing on at all.

Here is wet wool vs. no insulation:
Image
Here is wet wool vs dry wool:
Image

Its intersting that at its lowest temp wet wool was 75* when dry wool was around 90* which comes out to about 80%. So, maybe that old cliche I repeated is based on some form of fact, however, the full story is 80% of the warmth is colder than you would be not wearing it in the same scenario. Now, even with the tests it may not be as cut and dry as this- but I think the conclusion which makes a lot more sense than buying a synthetic bag because you expect it to get rained on is that everything sucks when it gets wet and its better to stay out of it if you can keep yourself dry and by a fire.

Now, back to down. I think its pointless to test sleeping bags soaked by a garden hose because keeping it out of the rain until camp is do-able, and even if it weren't you'd be screwed either way. But in extremely humid environments even if it is bone dry out of the pack the moisture absorbed out of the air prevents it from fully lofting. We have very humid weather here in the summer and very damp spring and winter, but I am not about to trade my down for synthetic. I think down can still outperform synthetic in this case. A better test for treated down would be to test the treated down vs untreated in a super damp environment to see if the treatment greatly improves loft. In this case they treatments might be really valuable.

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Re: warmer when wet, one more time?

#7

Post by sarge » Mon May 09, 2016 10:11 pm

For overnight and weekend trips, down won't absorb enough moisture from the air to make any difference down here---it might make a difference of trips of longer duration. My principal beef with down is that at the temps we normally encounter it doesn't seem cost effective to me, and the moisture thing is just and added arguement twoards synthetics under those conditions.

As to wool, I can tell you that as a reenactor I spent many a day wearing wool uniforms in the Texas summer and they were actually very comfortable (the shirts, not the jackets). Growing up in NH in the 1950s and 60s wool jackets and sweaters were the only thing we wore in winter. But then, wool was all we had back then---
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Re: warmer when wet, one more time?

#8

Post by TXyakr » Tue May 10, 2016 8:25 am

Idaho Hanger wrote:My unscientific opinion is that wet down collapses completely, making it virtually useless. By their nature, synthetics are less compressible which would lead one to believe that even saturated with water they would still be able to trap air to some extent because the synthetic fibers still have some structure.
This has always been my opinion and experience in these "Down versus Synthetic versus Wood" discussions.

Some downs (with treatments) are better than others, also synthetic insulation materials (fabric shell material makes a big difference) and various types of wool/alpaca can all vary a lot. Thinsulate(TM) seems to be less compressible than others and thus appears to work better when damp. I wonder if lower fill power downs work better than high when wet because they are less compressible? I.e. is 650 better than 850 or 900 when damp?

I have used and own many different brands and quality levels of dry bags (mostly for canoe/kayak camping) and they all fail at some point, usually at the worst possible time, so this is a big deal for me. Even though it is a pain, I pack my sleeping insulation and apparel in separate bags just in case one fails (gets damp or very wet). Also I make sure these smaller bags are on top with roll-top opening up as high as possible and strapped in well. Even on a very flat slow river a canoe can flip (I have seen very experienced people hit a hidden obstacle and the current flips them or it tips enough to fill with water) and even on a "dry weekend" your backpack can get wet when if you need to cross a creek and slip in deeper than expected, or your rain cover snags on brush, rips then it rains. Also I prefer to sleep without a tarp on relatively dry nights but even in the desert the dew can be much greater one night than the next. So my insulation is bound to get wet sooner or later, and has on occasions, mostly when it was raining all day and I had gear failures.

Wet weather rarely causes me to postpone or cancel a trip. If I had let rain keep me inside while growing up in the Amazon rain forest I would have been a total couch potato but never was. Heck we didn't even have a TV (most of the time, not allowed by parents) or electricity quite often and for weeks or months at a time. So down is great and I have some down gear but often take wool or synthetics instead. BTW people do die of hypothermia in the Amazon jungle, it can get very cold at night if you are wet or even dry. It snowed on me one time about half way up the Andes mountains of Peru. When front comes down from the mountains into the lowlands it can get very close to freezing there as well.

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warmer when wet, one more time?

#9

Post by Mophead » Tue May 10, 2016 9:12 am

Just to clarify I am not bashing wool and synthetic. In fact I really like wool. And even though a synthetic jacket would pack smaller and be lighter for the same warmth I prefer wool and poly fleece because they feel nicer and wool wicks sweat away like a champ.

I think where I take issue with the common wisdom is that once things get wet (or extremely damp) the loft retained is trivial. Even if it retained 100% of its loft you would still be losing so much heat through conduction that you would be warmer without it. It's like trying to warm up in a pool when the water temperature is within a few degrees of the air.

Dampness may be a different story and if you are expecting to never be able to hang your down gear to dry your down gear to dry the dampness during a wet trip then it might be better to go with synthetic. In most cases, just based on my own experience which may not match everyone's, I would say go with down if you can afford it. Hang it in the sun at lunch and every chance you can get if its damp. keep it dry and it won't do you no wrong :)

Edit: ok went in search of some tests and numbers and found this statement from Dridown:

"In an 80% relative humidity environment, an untreated 15-degree down sleeping bag loses up to 30% of its loft over a period of eight hours. A 30% loss of loft essentially turns a 15-degree sleeping bag into a 30-degree sleeping bag. DriDown™ sleeping bags avoid this loss of thermal efficiency by retaining 98% of their loft, keeping you warmer all night long on both short and extended trips into the backcountry."

Around here it is not uncommon to have RH of 90% in the summer but that drops through the day. If there were more info out there somewhere on down's loft at different humidity levels we could probably get a method for calculating when it would make sense to go to down vs synthetic.

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Re: warmer when wet, one more time?

#10

Post by Idaho Hanger » Tue May 10, 2016 5:54 pm

sarge wrote:My principal beef with down is that at the temps we normally encounter it doesn't seem cost effective to me
I would agree with that. When you're using a 40 or 50 degree quilt the weight difference between down and synthetic is minimal but the cost difference is significant.
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Re: warmer when wet, one more time?

#11

Post by TXyakr » Wed May 11, 2016 10:22 am

I have a fair amount of down gear but for some camping situations I still prefer synthetic insulation like poly fleece, Thinsulate and Permaloft etc. Mostly due to the loss of loft when it is very humid and raining non-stop for hours or days, no sun to dry it out. I also have some neoprene and treated leather (abrasion resistant for hunting in thick brush) for very wet conditions (but this doesn't breath well so mostly just use neoprene in a boat or swimming etc.) One problem with some fabrics and insulation is that they don't breath well and thus even when it isn't super humid I sweat easily with it on this causes my body to loose heat as soon as I sit still no longer moving (which caused me to sweat). I.e. walk up a hill to a deer blind or campsite then sit still hunting or cooking food etc. I need something that takes the wind chill off and can't carry a bunch of coats, jackets, sweaters for every time of day and activity.

The article attached isn't very detailed and is basically an ad for ThermoBall with PermaLoft but it and linked video discusses some differences between various types of synthetic insulation and down and when it might be a advantage. In my experience even hydrophobic down eventually looses its loft in very humid conditions and takes a long time to dry when the air is very cold and humid like in the NorthWest of USA and West Coast of Canada. (probably certain times of the year in Alaska, but I've not yet gone there.)

http://www.denalioutdoor.com/types_of_s ... ation.aspx

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Re: warmer when wet, one more time?

#12

Post by BillyBob66 » Wed May 11, 2016 11:50 pm

Yay, my thread came back to life! In fact there has been a flurry of activity!
Mophead wrote:Just to clarify I am not bashing wool and synthetic. In fact I really like wool. And even though a synthetic jacket would pack smaller and be lighter for the same warmth I prefer wool and poly fleece because they feel nicer and wool wicks sweat away like a champ.

I think where I take issue with the common wisdom is that once things get wet (or extremely damp) the loft retained is trivial. Even if it retained 100% of its loft you would still be losing so much heat through conduction that you would be warmer without it. It's like trying to warm up in a pool when the water temperature is within a few degrees of the air.

Dampness may be a different story and if you are expecting to never be able to hang your down gear to dry your down gear to dry the dampness during a wet trip then it might be better to go with synthetic. In most cases, just based on my own experience which may not match everyone's, I would say go with down if you can afford it. Hang it in the sun at lunch and every chance you can get if its damp. keep it dry and it won't do you no wrong :)

Edit: ok went in search of some tests and numbers and found this statement from Dridown:

"In an 80% relative humidity environment, an untreated 15-degree down sleeping bag loses up to 30% of its loft over a period of eight hours. A 30% loss of loft essentially turns a 15-degree sleeping bag into a 30-degree sleeping bag. DriDown™ sleeping bags avoid this loss of thermal efficiency by retaining 98% of their loft, keeping you warmer all night long on both short and extended trips into the backcountry."

Around here it is not uncommon to have RH of 90% in the summer but that drops through the day. If there were more info out there somewhere on down's loft at different humidity levels we could probably get a method for calculating when it would make sense to go to down vs synthetic.
Mophead, that was an interesting study you presented. And who knows, it may have been done in a scientifically valid manner, but you know how one day they a study tells us something(food, drug etc) is good for you and then a year or two later a new study comes out which tells us just the opposite? I am going to have to assume this study is invalid for my outdoor safety and comfort, because it contradicts common knowledge of hundreds of years of outdoor living, and my own personal experiences and testing, as well as that of many folks I know. (Yes, I realize you are not trashing wool, and not that it would matter if you were- you are just the messenger showing us an interesting study.)

So why would I call BS on this study?(no offense to you Mophead, the study data is the study data, all you did was show it to us) Even though the results of the study might be correct under the conditions that they rigged up for testing, it is still BS IMHO for practical real world experiences. Because the message seems to be that if I am out in a snow storm and my wool clothing became wet, I would be warmer trudging through the snow naked. Frankly, that is hard to accept, though you never know. Now, admittedly most of my personal testing has been with various synthetics vs cotton rather than wool, but I have many friends who have put wool to the test in the real world which included it getting wet. Kind of hard to believe I could have convinced them to strip naked to be warmer than in their wet wool.

Of course I do not know what the conditions for the test were, but I wonder if the tester included wool's faster drying time compared to cotton or untreated down? Again, sorry to say, I have not put wool to the test as I have synthetics like Polarguard(PG), but still he says "That would be Ross Gilmore's experiments with wool, which you can read over at Wood Trekker. His experiments led him to the following conclusion: no insulation is significantly better when wet than any other. A fairly damning outcome to all the previously extant knowledge on the subject.". In my experience, that is the biggest load of BS I have ever read, lab tests from one study be danged. The difference I have experienced between cotton and PG- and provided the results of my own testing- approached infinite. OK, maybe that is a slight exaggeration, but as a certain presidential candidate might say "It was Huuuuge!". The difference was warm enough while wet(soaked before hand in the sink) while hiking in rain/snow and bone dry after 30 minutes vs cold and still damp hours later even though I was back in the house. But this guy says there are essentially no differences? Well, he must be testing under different conditions than I have.

As I read further through the article, I can see several major flaws regarding how these results may or may not apply to real world outdoors experience. And in fact the author points them out. I won't quote them in this post since my post is already long. But one thing that stands out is that at about the one hour mark wool, after steadily rising in temp and being warmer at 50 minutes and for most of the test, takes a sudden rapid drop in temp (quite odd) and ends up 11F colder than DRY with no insulation. Ignoring the oddity of the fast drop at one hour for the moment, what stands out there is that DRY even with no insulation(in a warm room) is warmer than wet whatever. Well, that is not all that surprising, is it? If you are constantly soaking an insulation covering a heat source, you are going to get tons of evaporative cooling, while the control remains bone dry. But if we were to strip off naked in a snow storm, ditching our damp or even wet wool, we are not going to be dry, are we? Rather, we are going to be as wet as the wool we are removing and now exposed to the wind, plus no hopes now of our body heat ever drying out the damp wool once we get our rain gear on or under shelter.

Having said all of that, I can actually think of certain conditions where being covered by wet wool might be as bad or worse than nothing, at least until the wool dried out some. I will cover that in another post. But in the meantime, we can all easily put this to the test for ourselves, it's not hard to do. On you next winter day, hopefully with a cold rain or snow and windy, soak a cotton sweat shirt- the puffiest one you can find, and wring it out and put it on.(or maybe use untreated down soaked, but cotton is the worst IMO) Then go out for a mile or two hike(in your neighborhood for safety). Then if you can stand it and are not already hypothermic, just sit around in your house wearing the cotton until it drys. Let us all know how Y'all do with that. Then on another similar day, do the same with whatever synthetic or wool you would like to test. I find Polarguard and it's more modern versions like Climashield to be superb. But I have also had some very good results with polyester fleece. Whatever, pick your favorite. Y'all let me know if you notice any difference. ;)
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Re: warmer when wet, one more time?

#13

Post by BillyBob66 » Thu May 12, 2016 12:02 am

Here are some charts, independent tests conducted by the Hohenstein Institute FWIW, of wet vs dry synthetic insulations. Wildly different results than the testing done at Woodsy stuff. But, they were not testing wool, so not directly comparable. Go to the last post by Ayce and click on graphs. I will try to link the graphs after the main thread:
http://www.thru-hiker.com/x/index.php/f ... ead/21/#65
graphs:
http://www.thru-hiker.com/x/index.php?A ... board_id=1
http://www.thru-hiker.com/x/index.php?A ... board_id=1
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Re: warmer when wet, one more time?

#14

Post by TXyakr » Thu May 12, 2016 6:53 am

BillyBob66 wrote:Here are some charts, independent tests conducted by the Hohenstein Institute FWIW, of wet vs dry synthetic insulations. Wildly different results than the testing done at Woodsy stuff.
Those are some interesting graphs BillyBob66, it would be interesting to see more details on the conditions and testing procedures.

I couldn't find the original study at:
https://www.hohenstein.de/en/testing/te ... ng_1.xhtml

To actually be scientific it is by definition necessary to tightly control your parameters so that the test (experiment) can be recreated to verify the results. This obviously makes "real world" testing with many uncontrolled variable "un-scientific". Many years ago I spent the first part of my career designing tests, its not as simple as most "lay people" imagine it is.


Anecdotally (what most people misunderstand to be testing) I have found that wet insulation (jackets, wet suits, footware etc. not bedding) can trap my body's heat fairly well even when wet and even much better when I am physically active because I am replacing much of the energy (heat) lost by burning more calories at a higher rate. However, if I was sleeping with wet insulation (only a few rare times have I ever had this wretched experience) the loss of body heat would be much more noticeable. Water wicks away energy (body heat) much faster even if there isn't any wind or exposure to it. Some people quote things like "when wet your body will cool 25 times faster than if dry", this depends on many factors and often the rate of cooling is not that much faster. Here are some other considerations from the US Search and Rescue Task Force.

http://www.ussartf.org/hypothermia_cold ... juries.htm

Pardon me for being the boring scientist.

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Re: warmer when wet, one more time?

#15

Post by TXyakr » Thu May 12, 2016 7:06 am

More boring science: Why Most Published Research Findings Are False

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182327/

You can also Google for many less "scientific" articles in popular "non-scientific" publications... that are easier to understand for non-scientists.
For example:

http://www.businessinsider.com/why-most ... ng-2013-10

Edit:
This is funny, a Scientist friend of mine from grade school - H.S. (now a professor at a university in Stockholm, Sweden) posted a link to this an hour ago. Explains why scientists write in such a boring style, i.e. we get the heck beat out of us if we don't... and not published...

http://www.sciencemag.org/careers/2012/ ... -scientist

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