Synthetic Insulated Jacket Layering Review by Dane Burns

The typical question:

“I will climb Rainer this summer…next Orizaba, Kili, then Aconcagua! What do I need for clothes?”

Here are some thoughts on a well proven “systems approach” that you may have not had. It is a multilayer and multi use cold weather system based at least two garments. One garment with 60g insulation (part of your “action suit”) and the another with 100g insulation. (your “belay jacket”) The bench mark Patagonia DAS belay jacket is 170g insulation by comparison.

For really cold temps I have used up to 4 lighter layers or 280g of insulation, plus the resulting eight layers of nylon shell material that comes with it. 3 layers @ 60g and one at 100g. Surprised actually, at just how easy/well the system works. And how easily regulated for mid winter technical climbing at altitude, a cold bivy, a quick ascent of Rainier in summer or Fall/Spring alpine climbing. One garment at a time makes the buy in easier and the mutilayers should give you a lot of use/durability over the long haul.

I have a good many choices in the closet and find myself actually using variations of this system almost full time these days. Simply because of what is available for a “system”. It is the lightest, breathes the best and is the easiest to pack cold weather system I have used. Generally 2 layers of 60g. When it is really cold I’ll add the 100g as a third layer. May be even a fourth for an open bivy.

Sure a single thick down jacket will be the warmest and breath very well. Might even be the lightest. But down is fragile. Get down wet from sweat and you loose much of the insulation. Add a water proof shell and you limit the breathability. One big warm layer and you don’t have a lot of options for temperature control. There is defiantly a place for down garments and even multiple layers of down I think. But for technical climbing in marginal weatehr I suspect multiple layers of synthetics offer a better choice for most of us.

No where was Alaska mentioned in the opening quote. Nor was it addressed by me originally.

I’ve done multiple trips to the Alaska range. For time spent (45+ weeks) almost a full year on the glaciers there. Half of those trips included the summit on Denali. All but one were originally to more technical objectives first, just not very successful. Trivial record compared to many climbing there now. I’ve taken down jackets to Alaska twice. A synthetic bag once.

Below you are looking at an open bivy on Mt Deborah, Alaska using both, 4000′ off the deck. We did three that trip. Not the first or the last with that or other combos. But not once did I “sleep like a baby”.

I’ve not taken a down jacket or a synthetic bag to Alaska since ’80. Dated technology in many ways now for what I was trying to do. None of my partners or myself have had a cold injury…on any mountain while using synthetics. Would I take Down again now? Sure, depending on the objective..

There are some pretty amazing synthetic stand alone jackets available these days, the Patagonia DAS, The Arcteryx Dually, The MEC Tango among many. “Stand alone” meaning the biggest and most insulation in a “belay jacket”. All offer more than 100g insulation. They are sized to go over all your clothing. Some nice down choices in that category as well, Eddie Bauer XV, the RAB Nuetrino, Mtn Hardware Nilas and the Naronna Lyngen. Specific combos of lighter weight insulation offer even more choices.

Back to the question?

“At some point I’d love to get up Orizaba, Kili, Aconcagua, and wondering if jackets for something like Aconcagua is going to be overkill for a Rainier jacket?”

Polish route on Colfax n Feb ’10.

Mid weight down jackets like the Narrona Lyngen pictured right can be a good choice for climbs like Aconcagua and slightly warmer (but still chilly) environments.

The experience of using a 60g and 100g weight garment seems imo to be a better *combo* for the mountains listed, having summited on 3 of the 4.

The coldest I have ever been in the mountains was in the Alps in the winter of 2010/11. Great technical climbing just a 20 minute tram ride above Chamonix and only minutes from a latte and a nice salad.

May be I should have actually zipped up that last 100g layer. In Alaska I probably would. Well may be I would.

In the picture left, my base layer is a R1 Hoody. From the R1 out I am using a Atom Lt @ 60g, A Patagonia Nano Puff Pullover another 60g layer (which are all a part of my “action suit”) and finally a Atom SV @ 100g. The SV is my “belay jacket” for a total of 220g. I had stared the climb in a single 60g layer and as the day got colder I added layers.

Synthetic garments layer well. They will dry from body heat alone from the inside out. I have not found adding down layers to a pile garment of any sort as effective @ transporting moisture. Where a layer of Priamloft 1 does that very effectively.

One of the reasons the Patagonia DAS @ 170g is likely the most widely used synthetic belay jacket made. It simply works in a codl environment. Helps of course that Patagonia was the first to market a belay jacket based specifically on Mark Twight’s ideas and writings in EXTREME ALPINISM.

I think anything over 100g weight insulation as your last layer is generally over dressing for technical climbing in the US and Canada, short of the typical Alaskan climbing season and over nights in Canada or the Alps mid winter.

Lucky for us there are a lot of choices in my preferred combinations of 60g and 100g insulation.

Patagonia:  Offers a number of garments in these weights. The Nano Puff Series @ 60g and the 100g weight in the Micro Puff Series.

Arcteryx:  Has the Atom series..Atom LT in the 60g and the Atom SV in 100g weight.

MontBell:  Has the Therma Wrap BC which is unique with insulation 80g Body and 50g sleeves.  The Therma Wrap Pro is 80g though out.

RAB:  The jackets from RAB that I looked at are the Xenon @ 60g through out and the Alpine Generator with 100g in the body and 60g in the arms and hood.

But as much as these 8 jackets look the same..they clearly are not.

Patagonia uses a Primaloft 1 and Priamloft Sport for insulation. There is a significant difference in insulation value between the two Primaloft offerings. RAB is using Primaloft 1, the gold standard for synthetic insulation by most accounts.

Acrteryx offers the garments listed here in Coreloft. By Arcteryx’s admission its Clo rating is 5% less than Prmaloft 1.

MontBell is using their own Exceloft synthetic insulation. “Exceloft a combination of 8-denier compacted polyester tubing with extra-thin, 0.7-denier polyester thread makes the insulation remarkably compressible. In addition, Exceloft absorbs very little water, making it highly resistant to saturation and extremely quick to dry.”

My take from all that is either a combo of the Exceloft and their shell materials or just Exceloft makes a warmer garment for fill weight than Primaloft. But I have not seen Clo numbers to prove me right or wrong. Just a educated guess from using all these garments as they were intended and in a controlled environment simply for this comparison.

Which brings me to the real part of the story when you make comparisons. The outer shell materials are obviously really important for the intended use. As is the detailing and construction of the garments.

The combos I have used and like are a combo of pull over and and zip front. Generally I want a hood on the 100g layer but a hood on both is welcome as well. Although I think at times the 60g garments can be really versatile in both versions, with or without a hood.

Weights in a Men’s Large on my digital postal scale:


Patagonia Nano Puff Pullover

Patagonia Nano Puff Pullover 10.5oz (no hood)

Patagonia Nano Puff Hoody

Patagonia Nano Puff Hoody 13oz

Patagonia Micro Puff Hoody

Patagonia Micro Puff Hoody 18oz











Atom LT Hoody (vented) 14.6

Atom LT Hoody (vented) 14.6oz

Atom SV Hoody 18.6oz

Atom SV Hoody 18.6oz











MontBell Thermawrap BC (no hood and vented) 13.1oz

MontBell Thermawrap BC (no hood and vented) 13.1oz

MontBell Thermawrap Pro Hoody 16.8oz

MontBell Thermawrap Pro Hoody 16.8oz












Rab Xenon Hoody 11oz

Rab Xenon Hoody 11oz

Rab Alpine Generator Hoody 20.7

Rab Alpine Generator Hoody 20.7


How about a direct comparison of the 60 g garments no vents?

Patagonia Nano Puff Pullover 10.5 (no hood)

Patagonia Nano Puff Hoody 13oz

Rab Xenon Hoody 11oz
And 60g garments with vents.

Arc’teryxAtom LT Hoody (vented) 14.6

MontBell Thermawrap BC (no hood and vented) 13.1oz


Again as close as the weights are you will want to decide on a hood or a simple collar.  Be sure to look for a stretch fleece vent under the arms. Both will add weigh to a garment. And depending on your requirements may have some use.
The side venting on a shelled and lightly insulated garment is most easily identified in my mind with the Atom LT. I started using the Atom series several seasons ago and have written about it many times in the last 4 years. Mountain Hardware offers a version as does Mont Bell among others. For an active layer (your action suit main upper layer in cold weatehr) where you also need some extra warmth I think the idea is brilliant. Enough so that I have stopped using soft shell jackets. Changing out instead for a 60g layer of synthetic insulation with venting and a good hood.

It is lighter, warmed and breaths better than any soft shell I haev seen. The only down side is durability on rock.

Arc’teryx Atom LT in use @ -25C

When you you start thinking about using that 2nd layer for additional warmth you’ll want to notice a couple of things prior to purchase. Because it will be noticeable later from what I have experienced with these jackets. How well does the hood fit a climbing helmet? What kind of protection will the shell material offer in addition to the 80 or 100g of added insulation?

Patagonia Micro Puff Hoody 18oz

“Lightweight, 1.7oz 30-denier 100% recycled polyester ripstop, windproof shell made of recycled polyester and treated with a Deluge® DWR”

Arc’teryx Atom SV Hoody 18.6oz

Gossamera™—100% Nylon ripstop fabric with water repellent coating DWR

MontBell Thermawrap Pro Hoody 16.8oz

“Ballistic” nylon is one and a half times more abrasion resistant than other similar weight fabrics and boasts three times the tear strength of nylons that are almost 20% heavier. 100-wash rated POLKATEX DWR treatment.”
Alpine Generator Hoody 20.7

30D triple rip stop Pertex® Endurance outer and a Pertex® Quantum 20D rip stop lining
Fit? Fit is obviously such a personal thing. I am 6’1″ and 190#.

Here is how I have used these garments and my comment on the fit in that use.

Patagonia Nano Puff Pullover: I generally use this as an over shell for the Atom light. It is a big and boxy cut on me. Nothing flattering but I love the weight and warmth of this jacket/ sweater. Cuts the wind perfectly and protects the side vents on the Atom LT. My “perfect” combo weatehr combo.

Patagonia Nano Puff Hoody: This one is again big and boxy for the size on me. It is a little heavy and I don’t like the hood size. But for the weight and versatility of a full zip and a usable hood others might love this one.
Micro Puff Hoody: With Primaloft Sportinsulation this one holds little interest for me. Thankfully the price point reflects the use of a lesser Primaloft insulation. Same issues with Patagonia for fit and pattern on me for this one.

Atom LT Hoody & Atom SV Hoody:  I’ll admit these are go/to pieces for me. They fit like they were designed to layer together and every detail is almost perfect on both jackets. Almost. I don’t liek the zipper or not being able to adjust the hood. Both are trivial however as the over all designs are so good. Awesome hoods by themselves or in combo and over my Petzl helmets, which generally impresses me. I have zero complaints on these two after several years of use in some really cold conditions. They have a tailored athletic fit which I really like and never bind while climbing. I simply love the combo.

Monthbell Thermawrap BC (no hood and it is vented): I like the option of not having a hood on occasion. And I really like the vented style garments. AKA Atom LT. The 50/80g insulation combo adds a garment to this collection that is significantly different in warmth to others. I have to look for places to use the BC. And then decide why I should instead of an Atom Lt. But the BC is differnet enough and good enough to make the effort.

Montbell Thermawrap Pro Hoody: This is a jacket that made me realise I really am a gear snob. For it’s 80g weight it seems warmer to me than the Atom SV @ 100g by comparison. I really like the pattern and detailing of the Pro Hoody. The hood (which will take my helmets) and slick knit cuffs stand out. No adjusting required on the cuffs. As does the pattern’s cut. The Pro is an athletic cut and very fitted. This has become one of my very favorite 100g jackets…even though it is only 80g weight insulation. Go figure! Big surprise to me all round and a very pleasant surprise at that.

Rab Xenon Hoody: This is a sneaky little guy. It is not sewn through like the Patagonia 60g Primaloft. And it is two ounces lighter. It has a Pertex QuantumGL® 10 Denier shell fabric inside and out. There is more to this one than easily meets the eye. The only down side for me is the hood is good only under my helmet. The shell alone and the way RAB has done the insulation makes this one sort of “out of category” in a very good way. The Xenon is very warm for its weight. Better than the Nano Puff Series for warmth imo.

Rab Alpine Generator Hoody: If the Xenon is “out of category” the the AG is THE ringer here. It is punching way above its weight class. No one else using a Pertex® Endurance outer and a Pertex® Quantum liner. The hood is the best of the bunch with a hood imo. Given the fact the Acteryx hoods are VERY good. The sizing is spot on for layering and a ereal “belay jacket”. This jacket seem to me to be a specific built belay jacket here with no compromises. There are no bad 100g jackets listed here but the AG is a step above all the ones I looked at in this revirew. It is as obvious and as simple as that.

The others will do well around town. The Alpine Generator will obviously do well in the mountains.

The point to the conversation here is that as singles or as combos synthetic garments for climbing even in the harsh conditions can easily be justified. With the right combination of garments you could easily use a lighter one listed here for a chilly day cragging or a combination of several for a speed ascent of the Cassin.

Ready to buy or just compare prices?

Product Name Price Buy
Patagonia Nano Puff Pullover
Patagonia Nano Puff Hoody
Patagonia Micro Puff Hoody
Arc’teryx Atom LT Hoody
Arc’teryx Atom SV Hoody
MontBell Thermawrap BC
MontBell Thermawrap Pro
Rab Xenon Hoody
Rab Alpine Generator Hoody

There are 16 comments

Add yours
  1. Mike Layton

    Great review Dane!

    What’s your take on adding a windshirt over your base or R1 but under the next insulating layer to act as a mild VBL (or microclimate as Twight put it)? Also, where is your shell factored into your system?

    Got my own similar system, but I’m curious on your take.

  2. Dane

    Hi Mike, Lots of ways to use these pieces I think. I use a Atom LT and a R1 Hoody as my action suit top for cold weather alpine climbing and water ice. If I need more a Nano goes over it. Or just a Nano if it is warm enough. Depends so much on conditions. Atom LT sucks by itself in the wind. I don’t use a shell any more with this system. Seems redundant. Shells cuts the ability of these garments to breath. And all are shells anyway. I have used the microclimate idea as well and don’t generally use that idea now. Kinda like a VBL, at least for me it is limited to really cold weather. I do use a R1 hoody and a lwt shell alot when I can’t wear a Atom LT though. Hope that answers the question.

  3. CuriousKane

    Quick question. Is it important to have highest value insulation piece(down, primaloft) as close to skin as possible? Simply put consider two combos. Combo 1 being silkweight base under atom vs Combo 2 being R1 under atom. Does this have a noticeable difference?

  4. Dane

    Sure, you’ll be warmer in the R1. But only because you have more insulation. Not because of where the insulation is positioned. Don’t over think it.

  5. Tony

    Thanks for the article, Dane. When you are out and it’s snowing hard do you let one of your active layers take the brunt & get wet and then change it out for something dry, or when you stop do you just layer your system over the top and trust that the moisture movement, breathability and insulation of the system will dry out (sufficiently, if not fully) that wet layer, assuming you’ll need to strip back down to that layer to do some more work at some point?

  6. Dane

    Hi Tony, Hope the info has helped. I don’t climb in the rain..hopefully. But snow? I let the Atom Lt take that straight on if I can stay warm enough. May be a Nano Puff over it in the wind. Both shed snow easily unless it is really wet. Same conditions a soft shell will fail I think. I actually stay drier and warmer in these kinds of jackets than I ever did in my soft Arcteryx shells. At that point a hard shell would be more appropriate. I don’t normally carry a shell if that tells you anything.

  7. John

    How does your layering system change for bc skiing? Coming for doing the majority of my skiing in Colorado, I felt like I had it pretty dialed with cold dry weather. When you are doing an overnight what do you do for more insulation for your legs?

  8. Kevin

    Great review, thanks for the contribution Dane! The FA Igniter is glaringly missing from your comparison chart – 100g P1, 14oz. The FA Igniter + Atom LT weighs the same as the DAS, but, as you argue, is far more versatile. My Igniter matches up exceptionally well with my Arc’Teryx shell – one size up on the Igniter and they’re almost identical in cut (really shows how even Arc’Teryx has fallen prey to size inflation).

    Softshells are for cragging. Hardshells are for expeditions. Though I don’t think I’d want an Atom LT as my outer layer on a mixed route. How much more durable are the shell fabrics on these than what we are conditioned to believe? In other words, are these a full replacement in your shell system? You just told me to go buy an expensive softshell and now this (ha)!

  9. Dane

    I haven’t used a soft shell or a hard shell for several years while winter alpine or water ice climbing. Been no need. And all of the jackets listed have certainly been durable enough for anything but a full on off width crack. Although I am testing a pair of super light weight shells and a new soft shell again now. I don’t think I will be making any changes in my winter climbing kit. But I have ben surprised before. It is an on going arms race to keep current on the newest technology. The Cold Thistle blog has a recent tutorial on the use of belay jackets. It is worth a read I think if you have questions on how to use and layer these 60s/100s and the bigger belay jackets. Pretty much every reputable manufacture is making a decenht 60 and 100g insulated jacket. (or 30g, 40g, 60g, 80g, 100g combos) The Eddie Bauer versions and a couple of other company’s offerings will be compared with those listed here and highlighted on the Cold Thistle blog shortly. Easy enough to pick the jackets of this ilk you like for price, fit, insulation values, insulation quality, shell materials and features. There are enough differences between jackets (and now there are dozens of simialr jackets) that almost anyone should be able to find something that will work for them. Good luck!

  10. Dane

    John asked, “How does your layering system change for bc skiing”. Article and details listed here are how i use these jackets/sweaters climbing. How I dress for back country skiing, alpine touring, side hill or down hill @ a resort are four almost totally different subjects. And even that is so weather dependant. No matter. Short version? I don’t typically use anything I have detailed here for skiing. The Nano Puff Pullover is the one exception. As would be what ever insulation I might carry in my pack.

    • sikejones

      RE: BC Skiing- Soft shells work great for going to the bar, otherwise they dont breath well and dont pack
      well. Not warm enough for sitting, to warm for moving. Although i do
      like a non-insulated soft shell, makes a nice wind layer over capline. Synthetics puff coats are a must.
      I think the Patty Micro Puff is the best weight to warmth coat for
      skiing anyway, I am not much of an ice climber. The Arcteryx atom is a
      great coat but I find the vents too cold for standing and the insulation
      too warm for moving..another bar coat? Seems like a great ice climbing
      coat, the fit lets you move very freely. I try not to layer too much whiel skiing. it is a pain to have too many garments and to be changing all the time.
      So i usually just wear my capaline up and my micropuff down. Simple and
      light. If it is wet out then you need a hard shell also. Windy? well
      the hard shell or the non insulated softshell will work and thats my
      whole quiver.

      • Dane

        Skiing is a totally different use and topic for these garments. I too ski pretty stripped down. You’d freeze your ass off at the first belay if you dressed like that climbing. Patagonia Nano pull over is what I use as insulation and/or a wind shell. If I wanted something warmer the Rab Xenon Hoody 11oz would go in the pack instead.

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