Down w/WPB Shells or Synthetic Insulation?

[Ryan Jordan]

…and single wall vs. double wall.

OK, complicated systems, these winter clothing-sleep-shelter systems can be.

This thread is motivated by two different philosophies that are somewhat motivated by alpine climbing techniques, so consider that as a context/disclaimer for this discussion.

Mark Twight (in Extreme Alpinism)proposes the use of a pure synthetic system of clothing that has maximum breathability, on the rationale that (1) you’re going to get wet from within (sweat) and (2) you need to have breathable materials to dry your system out every night while sleeping. So, think Polarguard and highly breathable microfibers as shell materials.

Conversely, in a recent letter on the McHalePacks.com website Dan McHale emphasizes the necessity of having a waterproof breathable shell on down insulated materials.

Note that careful reading of these arguments indicate that McHale is not opposed to synthetics, but Twight certainly is opposed to the wpb shell-over-down philosophy.

McHale’s argument focuses on controlling external moisture from entering the system and maintaining a very tight microclimate to move sweat vapor through the system, while Twight seems more concerned about internally generated moisture (sweat).

Having used both systems, I’ve seen them both work reasonably well.

The questions I pose for discussion here are:

1. At what point/condition does the breathable-shell/synthetic-insulation system become more advantageous than the waterproof-shell/down-insulation system? I have to ask this question because we’re still looking at significant weight savings, especially for “winter weight” items, of down over synthetic (that gap is reduced for 1/2/3-season systems).

2. Is there utility for system components based on waterproof-shell/synthetic-insulation?

[Richard Nelridge]

I think that at this point it may come down to how much care one wants to put into monitoring and maintaining his/her clothing/sleeping system. In that what I mean is that if someone wants to take as little care in maintaining the dryness of the insulation of his/her clothing/sleeping system go with the synthetic materials and a breathable shell.

It must also be understood that no insulation, whether synthetic, wool, down, etc. will be as warm when wet as when dry. Lets face it, wet wool or synthetics may feel warmer than wet down, but if we get all our insulation wet it is going to feel cool as the moisture is evaporating.

When we perspire or have “imperseptible perspiration” we increase the amount of moisture in all insulation, lowering its ability to maintain body heat and increasing the weight of all the garments/sleeping system.

If however, one is willing to put the care into and monitor the possibility of wetting the down insulation, I would follow the suggestion made on the McHale Pack website, for maintaining the loft of the down with a WPB outer layer. This is especially true when using an eVENT outer material which is more breathable than any Gore product to date. Additionally, a WPB outer layer will also lessen the wetting of any synthetic insulation from the outside of the garment or sleeping system.

However, one has to be vigilent in minimizing moisture from perspiration and “imperceptible perspiration” from wetting out the down from the inside of down clothing/sleep system with the use of vapor barrier liners or vapor barrier clothing. Though not as important in warmer conditions, use of vapor barrier materials are more important when temperatures drop below 32 to perhaps 40 degrees F.

In order to help some in determining weight issues for those debating what system to use I just had a Vapor Barrier shirt in large (?) and Vapor Barrier pants in medium prepared by Stephenson’s warmlite (www.warmlite.com) that weighed 5.4 and 4.4 oz, respectively for a total weight of 9.8 oz. Vapor Barrier liners and clothing should work well for either synthetic and down insulated garments and sleeping systems. When not carrying a heavy pack or exerting too much energy and overheating the Vapor Barrier shirt and pants can be incorporated into a clothing system maintaining the microclimate next to the skin in cold weather conditions.

[Al Shaver]

A down garment with a wp/b shell is the lightest way to stay warm. If it’s not too rainy, if your shell performs both tasks well and you vent it and control perspiration expertly, if you’re a meticulous person this is a great system. If not, a wp/b shell over synthetic is a good solution.

A third option: highly breathable synthetics with no waterproof shell you reference from Mark Twight’s “Extreme Alpinism” may work under certain conditions for a miniscule percentage of users of this website…but probably not. Here’s why.

Mark has written a book by a professional extreme alpinist for extreme alpinists and wannabes. As a professional alpinist he can wait in basecamp or in the hotel for perfect weather. Once he starts a climb he moves continuously at rates of work, energy consumption and heat and moisture output that would send normal atheletic, honed mountaineers to the showers inside of 45 minutes. And he can keep this up almost continuously for over 24 hours if the climb and conditions require it. In his own words, when he runs out of energy and motivation, to move or even cogitate-he burns brain cells. He can’t afford to let his insulation become wet from the voluminous perspiration that he produces at his level of performance, he never slows down enough to get cold and he doesn’t have time or freedom of movement or free hands to put on a shell or adjust garments (if you’ve never climbed a 3000 foot vertical, near vertical or overhanging ice wall, you may find this difficult to understand). If the guacamole does hit the fan and it starts really raining he will utilize previously researched escape routes or shelter, call for helicopter extrication, climb or descend through conditions that would kill the typical hardman ten times over or simply climb until he collapses and dies.

The operative words here are “Professional” and “Extreme”. He does this for a living, he is at the apex of his industry. This is not Tony Hawk doing a 720 at the “Extreme” Games and then designing his line of video games. This guy is nothing like who we are or ever will be. Therefore his clothing concepts and the reason for them are of little use to the wilderness walkers and long distance explorers who populate this website. I’ve followed many of Mark’s exploits, I’ve read his book and I’ve heard him tell his stories in person and he’s one intense dude. I hope this background helps to put Mark’s concepts into perspective.

Cheers, Al

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