By the Numbers: Rethinking Fleece

That’s a lot of measuring and data, thanks

Yeah, fleece is heavy for the warmth.  You have good data that quantifies this.

Maybe fleece is good for heavy exercise when you don’t want much insulation or you’ll sweat

Run hot myself but this can help people who run cold even summer months.  There’s the various thicknesses and then wind resistant layers/panels too.

Think for backpacking … “active“ vs “at camp“ insulation needs to be the main planning consideration.

Maybe fleece is good for heavy exercise when you don’t want much insulation or you’ll sweat

I agree with Jerry. Fleece is great for hiking/skinning/skiing/jogging etc. in cold weather. And for grabbing a beer afterwards.

This will probably sound strange, but I also like the old Marmot driclime wind shirt for similar activities if it’s cold and windy or I will be moving fast. After all these years and new technologies, I still find myself reaching for it.

I’m loving this By the Numbers Series! Please keep it coming!!

I really appreciate the history included in the article; I think it helps navigate today’s current products.

I’ve always thought of fleece as active insulation, i.e. warmer wind shirts; info on breathability, water resistance, drying time, and wet performance could be enlightening.

Wouldn’t a fleece with high breathability and low R value function similarly to a wind shirt?

Since Patagonia funded the research on fleece pollution, I’m a little surprised to see them introduce new fleeces with no mention of micro fiber shedding. Does anyone else think about the pollution or do anything different to try to mitigate it? Based on top loading vs front loading washing machine results maybe gently hand washing fleeces is warranted?

Polartec might be trying to do something about micro fiber shredding…or maybe just marketing.

IME fleece’s effectiveness is awful in wind. so it needs a shell or windshirt as an add on–and that has to be considered in terms of its already high rate to warmth ratio. In other words, it weighs still more than its own weight in order to be effective in wind.

down is far warmer with less weight than fleece. Obviously it performs poorly when soaked, and fleece still provides some warmth in those conditions.

Down also tends to handle wind better than fleece.

I stopped carrying fleece on my backpacks in the Sierra. Too heavy! for its warmth to weight.

In the great outdoors, fleece is for when you expect your insulation to get wet.  Around town, who cares what it weighs?  Unless the referenced testing was done with wet insulation, I’m not sure how useful the results.  (I can’t read the article.)

Great article. Thanks!

It would be really great to see data on how they compare when wet, hot much water is retained when given a good squeeze and dry time.

Fleece in the High Sierra?  Yeah, probably not necessary.  But what about wetter climates?  The Pacific Northwest?  The Winds with its temperamental weather?  The Adirondacks which feel like a temperate rain forest?  In those areas, I still like having one fleece layer.  Also, based on the most recent reviews I’d be tempted to pick up a EE Torrid Apex and carry that rather than my Stoic Hadron down anorak.  (Who else remembers Backcountry.com’s Stoic brand before it disappeared and then re-emerged again as a casual front-country house brand? )

the article says that batt insulation has better than 4 times as much warmth for the same weight as fleece.  Lots of other good information.

I was looking at that again.

Stephen measures the clo/oz/yd2 of Apex as 0.58 or 0.59.  The claimed value is 0.82.

When I’ve measured it in my more crude setup I’ve got closer agreement.  I measured 0.92 compared to the claimed value of 0.82.

In Stephen’s earlier article he measured cork which has a known insulation value, as a verification of his test setup, and got good confirmation.

Measuring insulation is tricky.  Maybe there’s a scale error.  The relative comparison of fleece to batting, or different fleeces is still valid though.  Hmmm…

I think active insulation pieces have pretty much taken the place of fleece. They’re warmer for weight and with the right fabrics, quicker to dry.

Fleece is still a bargain compared to these pieces and will last forever, not so with syn insulation.

I still use very light fleece as base layers for shoulder season and winter.  Kuiu’s Peloton 97 hoody weighs all of 5 oz, ditto on their zip off bottoms. They make a nice sleep layer too.

Related to this article, Dave C’s “the fleece killer” is worth looking at

My thoughts exactly, except I’m using Montbell Chameece which is close in spec to Kuiu. Thinking they are both Toray fabrics? Light insulation layer on its own or under a puffy, windshirt or rain jacket.

yup- very close, yes to Toray as well

the Kuiu is nice as it has a hood and the zip off bottoms I thought originally, a bit of a gimmick, but that actually work really well.  cool/cold morning wear them out of camp, warms up drop your pants (but no need to take off boots/shoes) unzip and voila- base layer off

Bill – curious how your Montbell Chameece weighs ~5 oz as MontBell USA’s website gives the nominal weight as 9.7oz.  I made my own 1/4zip fleece top from Polartec 100wt fleece and it runs 8.6oz.  It’s a velour/fleece variant, but I don’t have the specific Polartec fabric style # handy.

Active insulation like Alpha Direct is great.  I have a Rab Alpha Flash jacket made out of the stuff.

In the article, the measured CLO/oz for Alpha Direct is .15 vs .12 for  “Ptec Thermal Pro HiLoft Azurro MY”.  That’s not a huge difference in CLO/oz between “traditional fleece” and “Active insulation”.   Worn on its own (meaning without some sort of additional wind blocking fabric on top like a wind shirt, rain jacket, or other woven fabric) I’d argue the Thermal Pro HiLoft would be warmer on a breezy day, and thus maybe a bit more functional, with the downside being it’s probably slower to dry.

I’ll admit I haven’t really put my Rab Alpha Flash jacket through any personal testing as a back country item.  I need to do that, because if I really like it, I may acquire some Alpha Direct and sew some additional tops for family / close friends.  I’m no Senchi Designs, but I’m capable of making a top or two of reasonable “MYOG” quality.

Mike- Have you ever used the Patagonia Capilene thermal weight base layers (or whatever they call them these days) and, if so, what would you say the difference would be between that and the Kuiu Peloton 97 material- warmth/wicking/wind resistance/odor issues?

I have; the thermal weight is a little heavier fabric, but the grid design of the Patagonia ones probably moves moisture better

if it’s really cold- I use the thermal weight as my base layers; just regular cold to cool :)  I use the Peloton 97 ones

a lot of time in shoulder season the Peloton becomes more of a mid-layer (and I use it sleep in as well), so it’s pretty versatile

neither offers too much in wind resistance, I would say equal as far as odor resistance- both are pretty good for synthetic

You are correct Jeff. My Chameece is 9.5 oz. I mentally confused it with my Alpha hoody at 5.5 oz. Thanks for catching that. I water the Chameece almost daily in cool weather. The Alpha is too delicate for daily use.

Pouring rain, hail, snow flurries, thick fog, and 40 degrees F for days and nights and days. Oh, and add some wind, and no sign of sun. That’s why a fleece still goes with me on every trip here in Alaska.

I use fleece not for the weight/warmth ratio but because it helps mellow out temperature and moisture swings with varying exertion.  I mostly have 100 weight items and think it’s about right.  If you need more warmth use a puffy, if you need wind resistance add a shell.

The fleece type that impresses me most is Polartec Powerstretch.  I think it manages moisture better than the Powerdry grid fleece.

One of the biggest complaints about fleece is also its strength- resistance to compression.  For alpine skiing against a -30 chairlift it is great to have a fleece layer.  On his South Pole trip, Ray Jardine suffered mild frostbite on the front of his thighs due to the incessant wind compressing his down pants- a fleece layer probably would have prevented it.  When it’s cold and you’re sweating the feel of fleece between your backpack and body is way better than a puffy squished there.

For me, on multi-day trips where I need insulation hiking, polyester fleece is the first layer over a light merino t-shirt.  On day trips I may choose a wool fleece or sweater instead.

Lots of discussion about the performance of fleece but almost no discussion about cost.  Standard fleece garments are CHEAP.  Combine fleece with a shell and you have a fairly versatile combination that performs even under wet conditions and you are not concerned with damaging fragile shell fabric.  For Summer+ (late spring+summer+early fall) in the alpine, fleece is just about perfect for those on a budget.

I have no trouble wearing a light fleece under a pack. It does not get damaged.
A windshirt over it, and the combo is fine in the snow.

Cheers

In terms of fleece micro-pollution, I rarely put mine through the washing machine. They respond well to vigorous sponging, look OK cosmetically and don’t seem to pong. I’m hoping that this will significantly reduce the environmental downside. If I’m wrong, please disabuse me!

Fleece is still pretty much universal in the UK because of its ability to perform well in damp and wet conditions, its versatility, its cheapness and its longevity. I find that batted insulation collapses too quickly and needs replaced too often, while down is pretty useless for active wear in a wet climate.

In dry cold, I’d use something else I guess, but that’s not something we experience much over here.

Do folks have recommendations on which fleece to consider if one is in the market? It looks like there are many options under 8 oz so I’m trying to stay under that number rather than go for a Patagonia R1 or something heavier.

Kuki – Peleton 97 Fleece Zip T – 4.5oz – $89 USD

Decathalon – Quechua MH100 Hiking Fleece – 7.4 oz – $20 USD

North Face – TKA Glacier Snap Neck – 7.40z – $60 USD

Arcteryx – Delta LT Zip Neck – 7.8oz – $115 USD