Question: Mountaineering clothing layering breathability question.

Hi all,

So here are my current clothing layering tops. This would be for Alpine climbing.

The question for you experts is:  How do the layer materials affect the overall breathability of the system?

My current setup is:

1- base, Arcteryx Delta shirt......mid: Arcteryx Atom Jacket / or Fleece jacket......outer: thin Puffy: EB Cirruslite down hoody 

....so my question is which Mid-layer in the system will allow most breathability when using all 3 layers?

.......the Atom jacket has 2 layers of thin nylon which is more wind resistant when worn as the outer layer (good), but will those nylon layers reduce breathability (bad) when under the down puffy, compared to the fleece as the mid layer under the puffy? or does it not matter?

Here are pics of each setup for a visual:

above with a fleece mid layer

.....hope this question makes sense?

Thanks in advance!!!

It very much matters, each one of those layers of thin nylon isn't very breathable and it does all add up, as a general rule I'd recommend avoiding individual layers of fabrics if you want breathability. Your fleece will be the most breathable of the layers you suggested, GSM is a good approximate for breathability in fleeces and other knit apparel such as baselayers. 

If temps allow and it's not too windy I'd use an atom instead of the down jacket, there wouldn't be many scenarios where I'd pick a down jacket as my main outer layer. 

Your layering system is a little anachronistic tbh, if you can I'd look at some active insulation pieces and pairing them with a wind jacket. Polartec Alpha is great, the patagonia nano air is popular but less breathable than something like a mountain equipment Kinesis. 

Are you familiar with the "action suit" concept?

Don't feel like you need to buy more kit though, people did a lot more with a lot less in the past. 

Test out both systems and see for yourself. That way you can evaluate how they move together as well. Maybe one is more breathable but it snags the upper or lower layer and causes other problems. Go test them and see which you prefer.

It doesn’t matter how breathable your mid-layers are if you’re wearing a down jacket over them. You should wear your down only when you aren’t moving or exerting. 

that guy named seb wrote:

It very much matters, each one of those layers of thin nylon isn't very breathable and it does all add up, as a general rule I'd recommend avoiding individual layers of fabrics if you want breathability. Your fleece will be the most breathable of the layers you suggested, GSM is a good approximate for breathability in fleeces and other knit apparel such as baselayers. 

If temps allow and it's not too windy I'd use an atom instead of the down jacket, there wouldn't be many scenarios where I'd pick a down jacket as my main outer layer. 

Your layering system is a little anachronistic tbh, if you can I'd look at some active insulation pieces and pairing them with a wind jacket. Polartec Alpha is great, the patagonia nano air is popular but less breathable than something like a mountain equipment Kinesis. 

Are you familiar with the "action suit" concept?

Don't feel like you need to buy more kit though, people did a lot more with a lot less in the past. 

Thanks! I'm open to new options.......what is the "action suit concept"?

I plan to wear the Atom as my outer layer most of the time, hence the appeal to a little wind protection. 

The action layer concept was first conceptualised by Mark Twight. It's very simple, you design your clothing system so that it's suitable for your activity and the conditions you'll be facing. You shouldn't have to be changing and modifying what clothing you're wearing, ideally that includes not using zips but in reality zips are assets for increasing the range of conditions you can wear your clothing in. 

Usually this involves much like what you have, a moisture wicking base layer, an insulating mid layer, and a weather resistant outer layer. 

The crux of an effective action suit is breathability of course, staying warm is easy. Ideally you want to be optimising each individual layer to be as breathable as possible while being adequately warm. Recent advances (e.g., active insulation pieces) in the outdoor apparel market have made this much easier. 

Down insulates best when close to the body. It’s also not very breathable, so outside of very cold conditions I’m not sure you’d want it while moving.

Also keep in mind that the hardshell is really only going to come out when you need it, for wind or moderate+ precipitation. It’s simply too hot to move in otherwise. Puffy plus hardshell while moving would turn you into an oven.

https://omegle.onl/

Pending your definition of Summer, you’ll probably be wearing a base layer and maybe a grid fleece or softshell for 90+% of your time on Baker and then layering up during any stops.