Please educate me on insulating pants

If only used when sleeping I guess I'd go with down … but that makes it a single use item.

Hi Jim,

I'm thinking the use of an insulating pant layer would be relegated to just for sleep and in camp. What other uses would a synthetic insulating layer afford besides sleeping and in camp? Like I said, I want to make sure I'm not missing something here.
Thanks.

I kicked around this question a couple of weeks ago, and I’m leaning pretty strongly toward sythetic with full side zip.

I plan on using the pants as a component of my sleep system, but I also want to wear them around camp, or when stopping to break for lunch, etc.

Full zip synthetic pants can be put on directly over my outer layer with less worry about them getting a bit damp and losing insulative ability. Also if they happen to snag on something,(snowshoe, ski’s, a branch while kneeling) down isn’t going to come pouring out of the tear.

I suppose you could make the same argument for synthetic jackets over down, but it’s a lot easier to take off your jacket and put the down underneath it than it is to depants, and I just see a lot fewer opportunites for snagging and tearing a jacket vs pants.

Unless you're in extreme conditions, you should only need them when you sleep.

A lot of people go with synthetic because usually temperatures that require it also mean wetness (i.e. snow). Since most folks don't go from the trail to bed and still need to conserve warmth, they put them on while cooking and sitting around camp. While sitting around camp, they are likely to sit on snow or other dampness, hence the further need for synthetic.

Get down if you don't think you'll get wet for compressability and unmatched weight to warmth ratio (Nunatak, Feathered Friends, etc.). Get synthetic otherwise like the BPL Cocoon.

I think if you only wear them to bed, then it might make more sense to just add more insulation to your sleeping bag. Much of the weight for any insulated item (including pants) is for the shell to hold the insulation. That's why it probably makes more sense to just add more insulation to your bag.

If you do need a pair for around camp and figure you can keep them dry, then yes, down may make sense. However, it is my understanding that at very low weights, synthetic is actually more efficient. This is because it doesn't require the same amount of fabric to maintain the down. This advantage disappears quite quickly as you increase the insulation.

I can think of lots of examples where having synthetic would be a real advantage, though. If you use a poncho without rain pants, for example.

Some of us who've made our own gear have found that when used in a thinner layer, the baffling material necessary to keep down in place adds more weight than what a synthetic system may be due to the ability of synthetics to stay in place with minimal sewing. Ensuring downproof fabrics that are still breathable also makes fabric selection more expensive and sometimes heavier in order to keep it suitable for any weather at all.

Paired with the complexities of working with down that require quilting or baffles and using it in making a low loft garment it quickly becomes hard to say that down has the edge once.

Well, that and your crotch can be a sweaty place for down to hang out for a week in a row…

As for camp wear, I consider it almost mandatory for a synth layer rather than down. If I'm changing out while still sweaty, or sitting out in fog/mist/rain/snow down isn't going to stay warm the whole trip. In a way it's a backup in case your down bag gets compromised as well.

This is strictly my opinion and I feel that only holds true to low loft down applications. If you need more loft, down gets a lot more appealing.

Personally, I love my cocoon layer, but I also use a pair of homemade down pants for REALLY cold weather. Not that most people are considering it, but as a heads up down is 100% harder to work with than most people think – my house was a mess that first time and I wasted a lot of very expensive materials. Second time I ended up setting up a tent in my living room and moving the sewing machine inside it just to catch all the down.

Hi everyone,

Thanks so much for the replies. This is exactly what I was hoping for. There's truly a lot of great arguments here for a synthetic layer over down.
What struck home for me was Joe's comment:
"In a way it's a backup in case your down bag gets compromised as well."
While it may be rare, this is an excellent argument, especially in very cold temps.
I can also understand a lot of posters points about when more loft is needed, it should be down all the way, but a thinner layer of synthetic could actually be more advantageous when high loft is not a necessity.
Again, thanks for the replies so far!

> Unless you're in extreme conditions, you should only need them when you sleep.
> A lot of people go with synthetic because usually temperatures that require
> it also mean wetness (i.e. snow).

I agree with the first sentence, but I am very confused by the second one. Surely if there is any chance of 'wetness' then you are going to be around 0 C, and that's quite mild conditions – not 'extreme'. Hum?

> Since most folks don't go from the trail to bed and still need to conserve warmth,
> they put them on while cooking and sitting around camp.
Depends how hard you have been working. By the time ( get the tent up (in the snow), I am very ready to retire inside it. So often the weather outside is not that nice anyhow. As for 'sitting around camp' – I'll do that horizontal under my quilt!
OK, OK, different conditions, different trips, different situations.

Me, I prefer synthetic trousers as they can take more rough treatment. In an emergency (or in just bad weather with high winds) I can wear them during the daytime, while travelling. In essence, my Thinsulate ski trousers are just that. And I do agree with OP that making the down baffles for a light layer is just too much work for too little return.

Cheers

Another point (or just a refinement of a previous point): I think the lightest synthetic filled pant is lighter than the lightest down filled pant. I'm not positive about that, but just by glancing at it, this seems to be the case. Of course, long underwear can be even lighter, but synthetic fill is warmer for the weight. So, single layer synthetic makes sense at the lowest weight, then synthetic fill makes sense, then down makes sense (as you move up the weight and warmth scale).

Here is a graph to illustrate my point (or confuse the heck out of people):
The horizontal axis represents weight. The vertical axis represents warmth. The colors are:

Red – No fill (fleece, wool, etc.)
Green – Synthetic Fill
Blue – Down Fill

As it might make more sense to use light synthetic pants, what ul pants are out there.

The bpl ones are sold out, the ones from montbell weigh about 10 oz and the plq pants from id are about 11 oz.

Is there anything else?

"The bpl ones are sold out"

Depends on the size you're looking for. I see all sizes but the XS are in stock. And then there's the set of smalls I have that are like new, black, that I'd be happy to sell for $90 including shipping.

Just to put forward a different POV, I use down pants if I expect it to be cold, for the same reasons Roger mentioned. In other words, I don't feel I need insulated pants at or above freezing, and below freezing getting wet is not such an issue. I also always carry a sit-pad to protect the pants if sitting outside at camp, and this keeps things dry. I have also hiked wearing down pants in extreme cold, but I wear knee high gaiters and a long raincoat or windshirt, which protects the pants from most hazards. I don't use baffled down pants as I feel the added weight and complexity is not worth the minimal gain in warmth.

Now if I were climbing high in the Himalayas, I would definitely be taking baffled down pants!

Go with your instincts and get the down.

I also have a pair of montbell down inner pants and I like them a lot. I use them for around camp and at night for sleeping.I have never had a problem keeping them dry or not ripping them. I take off my hiking pants and put the inners under my pants and then put my hiking pants back on to protect the inners.They pack tiny and loft up pretty good. In the snow I wear a hard shell pants over them for siting in the snow. I would get the western mountaineering flash pants or the flight pants if I were you. They weren't offered at the time I bought the montbell ones and I think they make better products.

Wow,

Thanks so much to everyone for chiming in. There are some devout advocates for both camps. Really, it seems, like many other things, it comes down to what is going to work best for each individual.
I'm still on the fence for a decision, but I think some more research and thinking about my intended use and needs for insulation will help me.
And, all the responses have been most helpful!

Well, try either Brigade Quartermaster for Softie Snugpak insulated clothes or GOOGLE "Snugpak" for really good synthetic insulated pants. I mean British military spec. good. I have the jacket and pants and they are WARM. Plus they are less expensive than U.S. made equivalents.

In early October this year I used the entire suit inside my WM Megalite 30 F. down bag and was very comfortable at 15 F. I tried that combo B/C I needed a good insulation layer for safety when hiking & camping at 11,500 ft. in the constant winds of Arapaho Pass in Colorado's Indian Peaks Wilderness. Kind of a "multiple use" item. Once I got back down to 9,000 ft. I took the suit off but it served its purpose.

I've also used the pants for deer hunting on a tree stand all day in 10 F. temps. and they were great.

"I've been researching an insulating pants layer for my sleep system and, knowing what I know of down and synthetics, I'm suprised to see a lot of people opting for synthetic pants for insulation."

It depends on the conditions you'll be in.

The worst I've had to deal with is a trip where it was about 35F and raining hard, creating 100% humidity. My hiking buddy and I both had our down quilts collapse as they sucked up the humidity in the air (neither had been exposed to direct water).

If you're in an area of only occasional rain and low humidity, then down rules. If you're climbing a mountain on the Alaskan coast I'd lean toward synthetics. In between, you make your own tradeoffs as to risk/reward.

Down is obviously lighter and more compressible, although the differences diminish as the amount of insulation is less. Also, synthetic is more tolerant of abuse (except for overcompressing during storage).

Per reviewed scientific lab tests versus what some individuals report in the forums appears to be at odds. 100% relative humidity, for any period of time, will result in these insulation maximum weight increases from absorbing the moisture in the air:

-Polyester (most common synthetic) 2%
-Down 10%
-Merino wool 30%

I am perplexed that the term "collapse" is so often applied to down and is never applied to Merino wool. I am also perplexed that an expert like Mike Clelland’s field experiences generally matches the lab conclusions related to down but is at odds with the reports of others. I wonder if the various ways of handling surface moisture on the shell, prior to stuffing, accounts for the discrepancy?

I can only report what I saw. By "collapse" I mean a significant reduction in loft. Not a precise scientific description, but it's what happened. I was using a Nunatak Arc Expedition quilt, which I had used on a previous trip that winter and had marveled as to the amount of loft. But on this trip the loft was significantly reduced by the morning. My hiking buddy saw the same thing on his Rab quilt.

Of course, I'm talking about hiking on the east coast, where 100% humidity levels can last for days, even in winter. Mike Clelland hikes out west, where humidity is substantially lower. It's not surprising to get different results, because we're testing under completely different conditions. My observations *where I hike* doesn't deny the validity of Mike's observations *where he hikes*, or vice versa.

"I am perplexed that the term "collapse" is so often applied to down and is never applied to Merino wool."

Collapse refers not to water absorption but to the loss of loft or weave structure when water is introduced. Some fabrics collapse readily while others resist it.

A perfect example of this is socks. Cotton socks, when wet, not only stay wet, but flatten out like crazy. Wool on the other hand may get wet and retain the water, but it maintains it's lofted structure better thus providing more insulation compared to similarly wet cotton.

Synthetic insulation, such as primaloft, when wet, stays roughly the same shape, only being partially degraded. Down will wilt massively when damp.

Wet insulation sucks away your body heat no matter what it is, but at least with a collapse-resistent material, once your body warms up the water, it can still insulate from outside conditions.

I bought myself a pair of the Patagonia Micro Puff Pants on sale awhile back because I thought for the extra few ounces they would hold up and deal with wetness better. The conditions I would use them in would be in very cold where I would expect to fall down occasionally or otherwise hit patches or rough terrain and where there would be a large discrepancy between my body heat and the air outside so that could get wet from a variety of sources. Mostly I just use mine for walking around town at -10F or -20F.

" I wonder if the various ways of handling surface moisture on the shell, prior to stuffing, accounts for the discrepancy?"

I would say most definitely. The only time I ever had noticeable loss of loft was when I had a GoreTex shelled sleeping bag. I felt secure enough with this shell (I was gullible enough!) to think that it meant I didn't need to keep water off my bag…WRONG. I also think this shell lead to more internal moisture from perspiration, so it was kinda a double whammy. I never weighed the bag before and after which is a shame.

A while back I bought BPL cocoon pants and overall I like the idea of them but … so far I've not been using them much. To the person that said that use depends on conditions, I'd agree and add that hiking/camping "style" and per-trip specifics also make a lot of difference.

I'll start on the Appalachian Trail in late February and wanted some sort of leg insulation but ultimately decided to bring silk long-johns instead.

The long-johns are of course not as warm, and a little more of a PITA to put on and take off, but here's my logic:

(1) The cocoon pants are worn externally, so I (at least feel like I) need to take more care when wearing them
(2) I anticipate wearing the long-johns in the late afternoon/evening, all night, and into the morning until I've hiked long enough to warm up. I think the cocoon pants would be too warm to hike in, so I would have to take them off before starting off in the morning — unpleasant in cold temperatures.
(3) If it's cold enough that my lower body is cold in camp, I'll just crawl half-way into my sleeping bag and eat dinner, etc that way — the sleeping bag is better lower body insulation and I'm already carrying it
(4) The long johns are less bulky in my backpack
(5) At 4.2 oz the long johns are 2.3 oz lighter than the 6.5 oz cocoon pants
(6) if I get the longjohns wet I can "walk them dry"

I'll carry rain chaps, and can also layer those over long-johns and pants for moving around in camp or even on trail when conditions suggest that.

I'm certainly not slighting the idea of insulated pants (!), just saying that the trade-offs work out differently based on multiple factors.