Comparing Fleece and Down midlayers

Does anyone have any practical experience comparing down jackets and fleece + windproof? 

Suppose I have a heavy 600g fleece jacket (like the Rab Outpost) with Polartec 360 gsm fleece and I wear a windproof on top of it. What kind of down jacket does this correspond to, roughly? 

What I am ultimately trying to understand is - in sub-zero temperatures, can I use the standalone fleece as an active layer and add a windproof while resting or at camp?

I see content on backpackinglight which claims the CLO/oz value of 300 fleece at 0.16/oz and 625 FP down at 0.92/oz and 850 FP down at 2.53/oz. These numbers don't make much sense to me, in particular the difference between the 625 and 850 FP down. It suggests that I need 2x the weight of 650FP down to get the same warmth at 850 FP down. This seems to be the spreadsheet with all the numbers.

I also see other claims  that R3 fleece is roughly comparable to 550 FP down.

I dont think heavy weight fleence is that sensible. Fleece is good at mounsture management, but down will be more insulating. Base layer and synthetic insulation is what I use these days.

When moving, I use base layer (merino wool or polyester) + outer layer (waterproof jacket, only if wet)

When not moving, I throw a synthetic belay jacket over it, or down belay jacket if I’ll only be out for a single day of cragging and I know it’s not going to rain.

Having heavy fleece or even a down mid layer seems like overkill, but I ice climb in Michigan, and it doesn’t get below 0F that often anymore.

Maybe explaining what activities you intend to do with it and what temps would help? If you’re hiking with a heavy pack on or climbing I feel like those would get too warm and sweaty. When chilling at a belay could make sense, but could also just get a warmer belay jacket.

The answer is no. 

A 300 weight fleece will not be warm enough with a wind layer to replace a down jacket, and it's too hot when you are active. 

In terms of equivalence if the 300 weight fleece is dry, fits snuggly, and you put a snug wind layer over it that would equate to ~1.5x the insulation of a ghost whisperer style down jacket and about 1/2 of a proper down parka. If you run hot you might get away with this, but then that makes the fleece terrible option when you are active. 

A 200 weight traditional fleece or an R1 style fleece is a much more useful piece, but they don't replace a down layer. 

There are synthetic jackets available now that are just about able to be the "one piece to rule them all" but that's a very hard thing to optimize for a range of temperatures.

The traditional base layer + 200 weight fleece (or R1 or R2 equiv) layer + wind layer + belay layer is still the most popular, and for good reason. The belay layer is the one that your vary based on temperatures, but the other layers pretty much always stay the same. 

Use the 300 weight fleece for around town in winter. Only folks that run extremely cold (looking at you ladies) or are climbing in extremely cold temperatures will find a 300 weight fleece ideal. 

I think that the days are R1 + windvreaker are also a bit gone. Baselayer and synthetic jacket seem better.

Wictor Dahlström wrote:

I think that the days are R1 + windvreaker are also a bit gone. Baselayer and synthetic jacket seem better.

It does seem to be moving that way

Wictor Dahlström wrote:

I think that the days are R1 + windvreaker are also a bit gone. Baselayer and synthetic jacket seem better.

Yes, this is my current system too. Merino base + Synthetic + Wind/waterproof if needed. I usually rent a down and was considering buying my own. Hence the question.

Chris Wernette wrote:

When moving, I use base layer (merino wool or polyester) + outer layer (waterproof jacket, only if wet)

When not moving, I throw a synthetic belay jacket over it, or down belay jacket if I’ll only be out for a single day of cragging and I know it’s not going to rain.

Having heavy fleece or even a down mid layer seems like overkill, but I ice climb in Michigan, and it doesn’t get below 0F that often anymore.

Maybe explaining what activities you intend to do with it and what temps would help? If you’re hiking with a heavy pack on or climbing I feel like those would get too warm and sweaty. When chilling at a belay could make sense, but could also just get a warmer belay jacket.

The objective is mountaineering to 6000M peaks in the Himalaya. I usually rent a down before the expedition, I have all the other layers. I never used fleece in practice. So when I saw the heavy ones like in the old movies, I wondered if they could substitute the down, especially as they are much cheaper! Thanks for explaining, I'll just buy the down.

Scott D wrote:

The answer is no. 

A 300 weight fleece will not be warm enough with a wind layer to replace a down jacket, and it's too hot well when you are active. 

In terms of equivalence if the 300 weight fleece is dry, fits snuggly, and you put a snug wind layer over it that would equate to ~1.5x the insulation of a ghost whisperer style down jacket and about 1/2 of a proper down parka. If you run hot you might get away with this, but then that makes the fleece terrible option when you are active. 

A 200 weight traditional fleece or an R1 style fleece is a much more useful piece, but they don't replace a down layer. 

There are synthetic jackets available now that are just about able to be the "one piece to rule them all" but that's a very hard thing to optimize for a range of temperatures.

The traditional base layer + 200 weight fleece (or R1 or R2 equiv) layer + wind layer + belay layer is still the most popular, and for good reason. The belay layer is the one that your vary based on temperatures, but the other layers pretty much always stay the same. 

Use the 300 weight fleece for around town in winter. Only folks that run extremely cold (looking at you ladies) or are climbing in extremely cold temperatures will find a 300 weight fleece ideal. 

Understood. Thanks for explaining!

Y C wrote:

The objective is mountaineering to 6000M peaks in the Himalaya. I usually rent a down before the expedition, I have all the other layers. I never used fleece in practice. So when I saw the heavy ones like in the old movies, I wondered if they could substitute the down, especially as they are much cheaper! Thanks for explaining, I'll just buy the down.

Damn, I mean this is totally different than my objectives or what most people on here are familiar with. It might be the case that it’s so cold at that high of altitude it warrants a heavy mid layer. Check out Colin Haley’s mountaineering layering guide.

I think if you’re going for extended trips many people recommend synthetic, because if it gets wet it’s not totally useless, whereas if down gets wet it needs to dry before being insulating again. Might not have that good of conditions on a trip to the Himalayas, so it might not have time to try.

https://www.patagonia.com/stories/colin-haleys-clothing-system-for-alpine-climbing-in-the-chalten-massif/story-95145.html

Y C wrote:

The objective is mountaineering to 6000M peaks in the Himalaya. I usually rent a down before the expedition, I have all the other layers. I never used fleece in practice. So when I saw the heavy ones like in the old movies, I wondered if they could substitute the down, especially as they are much cheaper! Thanks for explaining, I'll just buy the down.

I’ve got an XL BA fire tower parka (310g fill weight, 850fp, fully box baffled) if you’re interested. Pics should be in my post history in the buy/sell forum.

Chris Wernette wrote:

Damn, I mean this is totally different than my objectives or what most people on here are familiar with. It might be the case that it’s so cold at that high of altitude it warrants a heavy mid layer. Check out Colin Haley’s mountaineering layering guide.

I think if you’re going for extended trips many people recommend synthetic, because if it gets wet it’s not totally useless, whereas if down gets wet it needs to dry before being insulating again. Might not have that good of conditions on a trip to the Himalayas, so it might not have time to try.

https://www.patagonia.com/stories/colin-haleys-clothing-system-for-alpine-climbing-in-the-chalten-massif/story-95145.html

Yes, I have gone (on steep (40 - 60+ degrees) compact snow slopes. Roped up, no fixed ropes, single semi-technical ice axe) from summit camp to the summit between 6000-6500m in a thick down + feather jacket (maybe 200g x 750 fp) directly over a base layer. Perfectly comfy on the way up, starting around midnight. Hot af on the way down after sunrise. The challenge is the layering system for doing actual climbing (not just advanced hill walking) at that altitude.

I have almost decided to have a down vest as a 2nd midlayer - adds decent warmth, leaves the arms free to move. 

So - merino base + R1/R2 + down vest + waterproof with zippers in the armpits. And then have 2 levels of backup - (750 fp x 150g or maybe a bit bulkier, not sure yet) down jacket. Another similar synthetic jacket (Rab Xenair alpine).

Chris Wernette wrote:

Damn, I mean this is totally different than my objectives or what most people on here are familiar with. It might be the case that it’s so cold at that high of altitude it warrants a heavy mid layer. Check out Colin Haley’s mountaineering layering guide.

I think if you’re going for extended trips many people recommend synthetic, because if it gets wet it’s not totally useless, whereas if down gets wet it needs to dry before being insulating again. Might not have that good of conditions on a trip to the Himalayas, so it might not have time to try.

https://www.patagonia.com/stories/colin-haleys-clothing-system-for-alpine-climbing-in-the-chalten-massif/story-95145.html

That's a very useful article. Thanks for sharing!