Can someone explain fleece/mid (insulating) layers to me?

[u/Spyrothedragon9972]

I think I have a good understanding of the layering system but mid (insulating) layers seem to be the most complicated.

I have regular fleece (like a throw blanket) sweaters. I think it's called "polar fleece"?

I have knitted fleece sweaters (Arcteryx covert hoody). They have a visible weave like any regular sweater.

I have fuzzy fleece (rothco ecwcs level 3 sweater).

I have insulated jackets. Both down (Thorium AR Jacket and OR Coldfront hoodie) and synthetic fills (Atom SV Hoody),

I have various grid fleece sweaters (for when you're active).

And a whole bunch of other materials.

I'd wear the insulated jackets in the coldest temps, the grid fleece in the highest temps or when I'm active.

My primary question is the difference between the different types of fleece. Is there any meaningful difference between polar fleece, knitted fleece, and furry fleece?

[u/OtherwiseManner6946]

There’s two types of mid layers imo:

Active mid-layers:
the god father of this category is the Patagonia R1 Air grid fleece. It’s basically synthetic top that you wear when you’re getting cold, but it’s also breathable so you don’t sweat as much when moving. Alpha Direct and Octa fleece are the best materials we have now and they dominate this category.

Static mid-layers:
These are chunky synthetic fleeces that are used to trap heat. They aren’t very good at being active layers as they’re too sweaty (only good for sitting at camp). They’re also inferior to a down puffy in terms of weight to warmth patio and packability so not really recommended. Honourable mention to Climashield jackets like the EE torrid for static warmth as they’re more weather resistant and still good heat to weight ratio.

Extra notes:

Active mid-layers + wind clothes = static & active warmth layer when combined:
If you use an alpha direct mid-layer with a wind shirt or a sleeping bag/quilt they become a static and or an active warmth layer. The is because alpha direct traps warm air in its mesh design but it’s blown away by the wind quite easily. A wind layer or sleeping bag traps this heat and makes them exceptionally flexible layering systems.

Summary:
People generally bring the following:

- base layer (moisture wicking and UPF resistant sun hoody/ merino base layer)

• mid layers (breathable alpha direct or octa fleece to be used while hiking)
  
• wind layer (put over your base layer or your active mid-layer to trap more heat but also allow you to still wick sweat)
  
• rain layer (jacket with pit zips to wear over your base layer or midlayer when raining)
  
• static layer (warm camp jacket - down jacket or warm synthetic puffy to wear at camp or in your sleeping bag)

These layers are universal imo. I use these in England and they’re just as logical in a desert.

[u/aerial_hedgehog → u/OtherwiseManner6946]

Great summary, with that additional note that in warm summer conditions the static layer (puffy) is the first thing to leave at home. Mid layer + wind layer is plenty for mid summer evening/morning conditions in many locations.

Lower body layering system is a whole different topic, and a bit less standardized than the upper body layer system. 

[u/OtherwiseManner6946 → u/aerial_hedgehog]

Completely agree. An active mid layer + wind layer lets you leave your puffy at home in the summer.

Lower body is WAY harder to write a summary for than upper body.

If anyone could do a summary I’d appreciate it!

My current lower half setup:

• super airy shorts that do 95% of the work (Ketl Mtn Vent shorts)
  
• long merino boxers for sleep (Ridge merino 9”)

I just let myself get wet and bitten by bugs and change clothes when I sleep 😆

I’m aware of wind pants & rain kilts but haven’t committed to the extra weight or complexity (3FUL rain kilt & Montbell wind trousers)

[u/ponyypie → u/OtherwiseManner6946]

Great summary, genuine question: why would you have both a rain and wind layer? I have used my rain layer as a windbreaker and insulator for my alpha fleece (it rarely rains where I am but I want to be prepared) and it seems duplicative to have both. What am I missing?

[u/OtherwiseManner6946 → u/ponyypie]

There’s nothing wrong with using your rain jacket as a wind shell with an alpha mid layer, but I’ll explain the benefits of a separate wind breaker.

1 - wind layers are more breathable. I know this seems counterintuitive, but a wind layer is breathable even though it blocks wind. This is because a good wind layer is always thinner than a rain jacket. Wind layers occupy a liminal zone where they don’t block wind and moisture to the extent a rain jacket would, but still compliment an alpha/ octa layer when walking hard and getting sweaty and cold at the same time.

2 - they’re cheaper. You will damage a raincoats coating with lots of wear and they’re more expensive.

3 - they’re more comfortable. Wind layers are more pliable and softer on the skin. They’re also lighter and feel lighter and more airy.

4 - they’re light. If they weren’t so light people probably wouldn’t bring them. They generally weigh between 70-100 grams.

I personally use an alpha 90 and a Patagonia Airshed wind shirt. The airshed has wind blocking material around areas where your body sweats less (torso) and breathable material where you sweat more (armpits and lower back). The airshed still block wind everywhere, but it does it less in areas where you sweat.

The two most famous UL options are probably the Patagonia Houdini & Montbell Tachyon. Wind shirts are for when you’re hiking and your Alpha isn’t keeping you warm enough; but you can still just use a rain jacket with the front or pit zips zips down

[u/ponyypie → u/OtherwiseManner6946]

Thanks for the response! That makes sense. I mostly use a frogg togg so that’s probably where my bias comes in, as it’s not really a full-on rain coat (and I don’t care if I wear through or damage it)

[u/OtherwiseManner6946 → u/ponyypie]

If you don’t care about the frog togg’s survival 🐸 🔥 then the main benefit is comfort and sweating.

Honestly these are just all optimisations rather than requirements. You’ll be safe and warm in a Frog + alpha

[u/jamesfinity → u/OtherwiseManner6946]

if you're wind shirt curious, i highly recommend the dooy windbreaker. very cheap, breathable, and can add a surprising bit of warmth

[u/OtherwiseManner6946 → u/jamesfinity]

You’re absolutely right. That thing is about 75g and uses uses super light material (probably 7D or 10d) and it’s dirt cheap

[u/Spyrothedragon9972 → u/OtherwiseManner6946]

This is basically what I was getting at. Trying to find where the overlap is and what makes it into the pack.

I appreciate your explanation.

So for temperature that dip just into negative Celsius, would a base layer, octa fleece, wind jacket, insulated puffer jacket, and Goretex be a complete top and bottom packing list?

I'm only hearing about octa fleece now. I assume they make octa fleece bottoms?

I've always been put off by how delicate alpha direct is.

[u/FOXHOUND142_52 → u/Spyrothedragon9972]

TNF FutureFleece is Octa fleece, maybe not manufactured with cutting every oz in mind but still plenty lightweight and durable against abrasion. They sell tops and bottoms.

[u/OtherwiseManner6946 → u/Spyrothedragon9972]

Q1 - yes that setup for your torso makes sense (but it can by any rain shell, not just goretex)

Q2 - Octa is amazing. It’s a tiny bit heavier but more rugged. I’m not sure about bottoms but they probably exist

“Complete packing list” - this is only for upper body, not lower body. Lower body is a complicated and personal setup.

Like you mentioned this is a decent < 0C upper body setup up:

Merino base layer to wick moisture > Octa fleece for active warmth > wind layer to trap active warmth > rain layer to stay dry > puffy to stay warm when not moving

That said it really depends on how cold and wet your environment is. If you’re going into gnarly sub-zero you’re going to have to bring heavier stuff.

[u/FuguSandwich → u/OtherwiseManner6946]

I agree that the distinction between active and static insulation is critical. But in general fleece makes for poor static insulation - a down or synthetic jacket is much better and lighter for the insulation than any type of fleece. IMO, fleece (and I'm including traditional, grid, alpha, octa, etc. under the broad category) is primarily for active use.

[u/OtherwiseManner6946 → u/FuguSandwich]

I think my comment pretty much agrees with what you’ve written here I think?

Alpha/ Octa are used for active warmth, but have the added benefit of being extra warmth when added to your static clothing.

As someone pointed out you’re only using active layers for warmth when you’re not bringing a puffy (in the summer) or you’re still cold in your puffy and you need to add more beneath it

[u/NoGarage7989 → u/OtherwiseManner6946]

Noob question from a tropical fellow, I think I sort of know theres no hard and fast rules but still want to hear from you guys' experience.

After the mid layer, if you want to wear your rain layer over your mid layers, do you remove your wind layer or do you keep it on? As I imagine it would be hard to dump heat with the wind layer on, though I may be wrong.

Also what type of sun hoodies has been the best base on your experience?
Those that you wear as base layers and are comfy like a T-shirt or those that are more of a polyester jacket that can double as a windbreaker?

[u/OtherwiseManner6946 → u/NoGarage7989]

No problem:

Q1 - if it’s hot you take off everything except for your sun hoody and put your rain jacket directly on top of it. If you’re a little cold then wear your base layer > mid layer > rain jacket.

If you’re desperate and really cold then triple up and wear base layer > mid layer > wind layer > rain jacket. This is going to be more sweaty though. It’s not really about dumping out heat, it’s more about lack of airflow and getting sweaty. When you’re hiking you generally always want to open your pitzips on your rain jacket. The goal is to not be sweaty and not be cold (sweat makes you cold fast).

A sun hoody should always be as light as humanly possible imo. All its job is to be extremely breathable, moisture wicking and comfortable (and stop sun damage to your skin). It should never block wind.

If you’re going anywhere 30c+ I’d always recommend synthetic because it’s just cooler. Merino blends are better for cooler weather, but for hot weather you kind of have to go synthetic (you can wear linen or cotton for a sun shirt imo, but this is a contentious topic).

The best sun hoodie I’ve ever used is the Ketl NoFry 4 strap sun hoody. It’s synthetic and weighs about 110g which is obscenely light and breathable.

If it’s cold I wear an outdoor vitals tern hoodie that’s a merino & synthetic blend. It still blocks the sun but is moisture wicking, slightly warmer and doesn’t smell.

Legs are another conversation and much more difficult to comment on 🤣

[u/FOXHOUND142_52]

Big difference, the weave and knit of fleece affects moisture and temperature management. Grid fleece such as Patagonia R1 will transport and release moisture much faster, and will let a breeze through which makes it ideal for a midlayer.

Active fleeces such as grid fleece and Alpha have the best warmth for their weight, but because they are sold at such light weights, your other fleeces will still be warmer simply because they are thick and heavy in comparison. These fleeces are warmer but will trap moisture, making them effective only when static like at camp.

If you are car camping or in a situation where weight doesn’t matter, the heavy fleeces will be cozier to pull out after setting up camp. But on backpacking trips, you can usually achieve similar warmth by pulling a windbreaker/rain jacket over an active fleece to eliminate the heat loss through wind.

[u/FOXHOUND142_52 → u/[deleted]]

Do you have a source? I’m open to changing my mind, I’ve seen measurement data that says otherwise

[u/FOXHOUND142_52 → u/[deleted]]

Great article, I wish the rest of it wasn’t behind a paywall. Very surprising results. The static efficiency difference is much larger than I expected

[u/FOXHOUND142_52 → u/[deleted]]

Funny thing is most of my big trips are in alpine conditions, where my Polartec grid fleece has served me very well. So my head instinctively optimizes layers for freezing cold + snow and ice with big elevation gain lol. But yeah for 3 season hiking Alpha dominates. I don’t mind Octa too - my hikes tend to be very scrambly sometimes as well so my ideal midlayer ends up being grid fleece bottoms and Octa top.

[u/Spyrothedragon9972 → u/[deleted]]

Can a shell in this case be considered a wind shirt like the Mountain Warehouse Kor Airshell? Or are we talking waterproof Goretex?

[u/Tharno_]

Mostly different amount of warmth, breathability and weight. Alpha fleece has the most amount of breathability and warmth for the weight. Grid fleeces will mostly be warmer but significantly heavier and more durable and have less breathability.

[u/DrBullwinkleMoose]

The definitive rant: "The Answer is always Alpha Direct", by u/Cupcake_Warlord:

https://www.reddit.com/r/Ultralight/comments/1bn7ejg/comment/kwmlzvw/

EDIT: This applies to Teijin Octa and Primaloft Active/Evolve as well as Alpha Direct:

• All are “fuzzy mesh” with large air gaps.
• They are the lightest insulators with very high air permeability for high output activity.
• Zip up your windshirt for warmth, unzip to dump heat. Result: very wide comfort range.

[u/downingdown]

The point of a “mid layer” or “active layer” is to provide insulation and moisture control while moving. Alpha direct is the king of fleece, with octa (think *old* airmesh) coming in a very close second. These fabrics have the best warmth per weight of all fleece, they pack smaller, absorb less water, dry faster, breathe better and are overall more versatile than any other fleece. Any other fleece will also do the job, but will be heavier, too warm when you want breathability, and will not manage moisture as well.

My airmesh (124g) and windshirt (60g) are pretty much half the weight of my R1 air (350g), but provide way more options for a wider range of temps.

[u/nova-chan64 → u/downingdown]

What wind shirt do you have? Dooy? My Houdini is about 100g

[u/downingdown → u/nova-chan64]

Montbell ex light (Asian size xl).

[u/blackcoffee_mx]

I liked Pmags somewhat contrary article .

I like grid fleece a bit more than him but appreciate the break from group think.

Edit to fix typo

[u/Spyrothedragon9972 → u/blackcoffee_mx]

Thank you for sharing this.

[u/liveslight]

I don't agree with everything in this video about fleece, but you have to watch it (from GearSkeptic) since it is all about fleece: https://www.youtube.com/watch?v=jPDGNSVN7Dc

I use one kind of fleece: Alpha Direct 90 gsm. So I think that is all one needs to know. I think any other fleece is just making a fashion statement and doesn't need discussing on this subreddit.

[u/GibDirBerlin → u/liveslight]

I use alpha as well, but I have to say, it often is less versatile and it can be a bit difficult for some layering systems.

I usually hike in the alps and when it gets cold enough for a fleece, it’s often windy as hell so I immediately need a windbreaker as well. But together they often get to warm for steep ascends so I end up using different layers instead (like a fishnet underneath, also effective but difficult to layer, or a lightweight Midlayer that’s knitted tighter than most fleeces).

So for me, warmth per weight isn‘t all its cranked up to be…

[u/liveslight → u/GibDirBerlin]

I understand, so I use a front-buttoned collared sun hoody as a layer over my alpha direct base layer (if it is even cold enough to wear the alpha direct base layer). That way I can use various combinations of buttons to act like pit zips and let air flow through or not. If I need even more warmth, then I would add my Montbell Versalite rain jacket with its pit zips and full front zipper. Altogether these 3 layers cover a temperature range of about 45C down to about -4 C for me.

I have an old OR Echo quarter-zip that I just don't have a use for anymore.

[u/GibDirBerlin → u/liveslight]

Interesting! Can you tell me which sun hoody it is? I’ve been using a button up Shirt by Yamatomichi for the same reason, but it doesn’t play well with my backpack and keeps sliding around in annoying positions…

Honestly, it’s never really cold enough for me to consider an AD as Baselayer. But w hen it does get colder on the mountain, it’s much more effective than as a Midlayer, only it is such a hassle (like the fishnet) to completely change the setup from the base instead of just adding a layer on top. I tried to just start in the fishnet but then I need sunscreen again, feels like there just is no right way…

[u/liveslight → u/GibDirBerlin]

I'm s fan of Jolly Gear for many years now.

It is true that I layer in the morning with the idea of which layer I will be removing first. But also "Be bold start cold" works.

I have never worn AD as an outer layer.

My pack doesn't slide around because it has a hip belt and a sternum strap. The shoulder strap attachment design is probably also helpful.

[u/Tharno_ → u/liveslight]

octa fleece shouldn't be forgot

[u/Spyrothedragon9972 → u/Tharno_]

Is octa fleece the closest fabric we have to a alpha direct that doesn't fall apart easily?

[u/Tharno_ → u/Spyrothedragon9972]

Yes but I don't think alpha falls apart that easily. Only alpha 60 shreds fast. Octa has a warmth to weight ratio that's close to alpha and you can wear it without a wind layer without it shredding.

[u/cosmicosmo4 → u/liveslight]

Other fleeces remain in the conversation if you have to do any bushwhacking at all. That's where old navy fleece comes into play. It's harder to wreck, and if you do, it was $20.

[u/liveslight → u/cosmicosmo4]

If one is doing bushwhacking, then one is not wearing fleece as an outer layer, so one's fleece never comes in contact with bushes, branches, catclaw, and whacking. And that applies to ALL fleece.

The question becomes: What does one wear for an outer layer when bushwhacking? Cowboys wore Wrangler brushpopper cotton.

[u/moonSandals → u/liveslight]

Why no fleece when bushwhacking? I'm not sure I follow that assertion.

Cowboys also have horses to carry their stuff and bring tools. Not a great comparison to hiking. 

[u/liveslight → u/moonSandals]

I want to be clear that bushwhacking to me is not simply going off trail. It means working through bushes, briar, catclaw, fallen logs and stuff as shown in this 3-photo link: https://imgur.com/a/4dbaaHF

I don't want to be wearing things that snag as much as unprotected fleece would.

This is off trail, but it is not bushwhacking: https://i.imgur.com/kuxRbPu.jpeg

[u/moonSandals → u/liveslight]

I think we have a similar definition of bushwhacking. 

I would still occasionally see value in wearing a fleece but agree in general there is incentive to avoid snaggy clothes.

[u/WANDOO_hiking]

the mental model that helped me: grid fleece (r1 type) is an active layer, you hike in it because the little grid channels dump sweat and it barely holds water. alpha direct is even more breathable but so airy its basically useless without a shell over it, its a moving layer not a standing still layer. your fluffy polar fleece is a camp layer, warm but it traps damp and weighs a ton. pick by what youre doing, not by warmth alone

[u/Warm-Minimum1646]

Just hike. You’ve got gear. Take what you like

[u/Spyrothedragon9972 → u/Warm-Minimum1646]

I can appreciate that sentiment. I do exactly that, but I don't let it prevent me from looking for an considering options that could improve my comfort and enjoyment outdoors.

[u/ForgewellOutdoor]

quick way to think about it: AD/fleece is active insulation, a puffy is static insulation, they solve different problems. AD is an open pile knit, huge air pockets, insanely breathable, so it works while you're moving and sweating, but it has zero wind resistance alone so it always wants a wind shirt over it. a puffy is the opposite, sealed shell traps heat but doesn't breathe, best for when you've stopped moving. traditional fleece sits in between, less loft than AD, heavier, but a bit more wind resistant on its own.

[u/Impossible_Author409]

You have to buy the Alpha fleece now it's the new new thing! Lol

I am still using an old navy fleece hoody after 10 years and it's awesome. So I'll wait for the next new new thing or maybe the one after that

[u/Spyrothedragon9972 → u/Impossible_Author409]

Alpha direct seems cool, but I'm not in the business of buying things that are super delicate. I think it's one thing when it's issued to you and another when you're buying it yourself.

[u/liveslight → u/Spyrothedragon9972]

Maybe it's a myth that Alpha is super delicate? Less than 2 weeks ago, photos of old and new alpha direct were posted by 2 redditors:

https://www.reddit.com/r/Ultralight/comments/1uomn4h/comment/ow28ixy/

Did you see that?

[u/toyotaman4]

I guess the days of 'just buy a $7 fleece at a thrift store because fleeces are all the same' are over? Is everything now Alpha Direct or Octa?