Down vs Synthetic - Location and Humidity concerns

[redkyte510]

Hi All,

I've been doing a lot of reading on this site to do with making my own quilt/pod (see my DIY - Burrow / Pod design thread here... still in the very early stages I might add).

My reading has led me to the concern that Down is so susceptable to moisture ingress that the climate of the UK in which I will use the system will be deleterious to the effectiveness of the down. The Humidity here tends to be in the region of 65% - 85% all year round, with weeks spent at over 80% if not over 90%. Whereas the N. American Continent is significantly dryer (generally) at the 50% - 60% mark.

So my question is:

Do I just make my system synthetic and accept the weight but guarantee being warm

or

Do I go for a down system, but overstuff it by a few ozs to get the lofting requried?

A side question is, I have heard tell of a tool/spreadsheet somewhere on here that allows one to calculate the loft requriements of a quilt for a given temperature range. Can anyone point me to this resourse please?

TIA

Red Kyte

[MAD777]

I've camped all my life in Florida, where humidity is equal or greater than the UK, and have used down exclusively with no problems. But here is the caveat; time spent per trip is 3 to 4 days max. From my experience, down is fine for short trips, even in extreme humidity.

Others who have thru-hiked the Appalachian Trail can chime in about long term experience. The 2400 mile AT follows the Eastern forests of the US, where at least the southern half is generally humid.

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[redkyte510]

I've camped all my life in Florida, where humidity is equal or greater than the UK, and have used down exclusively with no problems. But here is the caveat; time spent per trip is 3 to 4 days max. From my experience, down is fine for short trips, even in extreme humidity.

Others who have thru-hiked the Appalachian Trail can chime in about long term experience. The 2400 mile AT follows the Eastern forests of the US, where at least the southern half is generally humid.

Mike,

Thanks for this. My experience of down is fairly limited so any help is appreciated!

[BillyBob58]

Hi All,

I've been doing a lot of reading on this site to do with making my own quilt/pod (see my DIY - Burrow / Pod design thread here... still in the very early stages I might add).

My reading has led me to the concern that Down is so susceptable to moisture ingress that the climate of the UK in which I will use the system will be deleterious to the effectiveness of the down. The Humidity here tends to be in the region of 65% - 85% all year round, with weeks spent at over 80% if not over 90%. Whereas the N. American Continent is significantly dryer (generally) at the 50% - 60% mark.

So my question is:

Do I just make my system synthetic and accept the weight but guarantee being warm

or

Do I go for a down system, but overstuff it by a few ozs to get the lofting requried?

A side question is, I have heard tell of a tool/spreadsheet somewhere on here that allows one to calculate the loft requriements of a quilt for a given temperature range. Can anyone point me to this resourse please?

TIA

Red Kyte

Well, this is the eternal debate. But first thing I would like to say: the weight penalty, particularly for quilts above 20F, is quite minimal, and bulk would be a bigger issue, especially for those with very small packs. And if you feel a need to over stuff, there goes a lot of any weight benefit right there.

Before you call me crazy, consider the original WB Yeti that used about 10 oz of torso sized Climashield XP insulation and weighed roughly 18 oz total, and was rated about +5F, and was well tested by one well known user here(a warm sleeper)to well below zero F. Only a few of these were made before a temporary problem arose obtaining CS and there was a switch to down, the long proven, excellent zero rated WB Yeti. Weight? 18.5 oz, without any added over fill. So that is not exactly a huge advantage in weight compared to the original, even before considering moisture management. But it will no doubt stuff smaller.

Want another example? The AHE Jarbidge CS Apex is conservatively rated 25F, and has been used by many successfully to that temp and even below. Now, it is not quite full length at only 58" long, but not far from it. It weighs about 19 oz. A typical high quality 73" 20F down model will weigh 23.7 oz. But that is 26% longer. Adjust for length, and you have no more than a 1 oz difference, before adding over fill to help with humidity. My AHE Ridge Creek, a custom fit for a WB Ridgerunner, weighs 19.75 oz including 4 corner mini biners and stuff sack. The down equivalent is rated 5*F warmer and is listed as 17.25 oz(including stuff sack?).

So you can see the warmth to weight ratio differences are not huge, and almost non-existent if you feel you must add over stuff to make up for humidity or condensation. Volume will be a bigger consideration, depending on pack size.

Many report never having issues with their down and moisture, particularly for shorter trips or if drying by sunshine or dryers is available.
( folks on longer trips on the humid Appalachian Trail sometimes take breaks in nearby towns where gear can be dried) Others report losing loft on multi day very damp trips, even when no rain gets on the quilts. I have seen this happen with friends and at least once myself. These were 5 day trips, and the quilts were rated a good bit warmer than temps encountered, so no one got cold. But there was concern about if the trips had been even a few days longer. One good day of bright sunshine would have solved the problems, but this did not happen. The ones with synthetic had no issues from moisture whatsoever, even without any drying opportunities. Loft remained about as it was at the start. EDIT: on one of those trips where my friend was shocked to see so much loss of loft, I even made an error and soaked the foot end of all of my synthetic insulation on the very first night. Made no difference in warmth that night, and was fully dry- NO sunshine - by the next nights camp, and stayed that way until the end of the trip)

These days treated down should solve any concerns. I have some of this, so I hope it works as claimed. But I read some negatives about it, from well respected people and companies. That it doesn't work as well as claimed, or wears off, other problems. So I am not sure what to think about that.

[Just Bill]

My personal opinion:

Above 45*- synthetic can be equal and often better (Primaloft Gold) than down on many common metrics.
I would choose synthetic easily in these conditions.

Between 25* and 45*- Length of trip and your conditions should be the deciding factor. Your comfort with these conditions and your gear is important too.
As Mike mentioned... short enough trip and it doesn't matter. At some point if you have to size up your down/overfill to fight humidity... how much further ahead are you really on a cost/weight basis. Pack size will likely be better.
This is a coinflip if you have very wet conditions- but I tend to go with down in favor of pack size and weight.

Below 25*- I will almost exclusively use down.

I build 45* Primaloft Gold Quilts, but the only time I built any 25* versions were for:
Older female backpackers (who needed a warmer quilt for summer conditions.)
Those who were allergic to down.

Otherwise even if am 'making money' off selling synthetic for those temps I will usually talk you out of/talk you through it for that middle range quilt and strongly suggest you buy a down quilt from someone else rather than sell you a 25* synthetic.

The only deep winter trip I'd take synthetic would be for a prolonged trek in below freezing conditions which 99.9% of us are unlikely to ever take.

[rweb82]

The other important thing to note regarding down vs. synthetic is the lifespan of the materials. A properly taken care of down garment (quilt, jacket, etc...) can last decades. Down will not break down (pun intended) through repeated compression cycles like synthetic fibers do. As such, a synthetic quilt will need to be replaced more often than its down counterpart- usage being equivalent between the two.

I'm not saying synthetic is bad at all. In fact, the synthetic insulation most cottage vendors use today is quite good. And companies that produce 100% synthetic items have a great reputation (i.e. Arrowhead Equipment). I prefer down for the smaller pack volume. I also do not add overfill to my quilts- as most cottage manufacturers already overfill their quilts by 15-20%. But if pack volume is of no issue to you, synthetic may be a great option- especially if price is of concern. The counter argument to the price issue is that most vendors now offer budget down quilts that are in the same price-range as a good synthetic quilt.

[redkyte510]

My personal opinion:

Above 45*- synthetic can be equal and often better (Primaloft Gold) than down on many common metrics.
I would choose synthetic easily in these conditions.

Between 25* and 45*- Length of trip and your conditions should be the deciding factor. Your comfort with these conditions and your gear is important too.
As Mike mentioned... short enough trip and it doesn't matter. At some point if you have to size up your down/overfill to fight humidity... how much further ahead are you really on a cost/weight basis. Pack size will likely be better.
This is a coinflip if you have very wet conditions- but I tend to go with down in favor of pack size and weight.

Below 25*- I will almost exclusively use down.

I build 45* Primaloft Gold Quilts, but the only time I built any 25* versions were for:
Older female backpackers (who needed a warmer quilt for summer conditions.)
Those who were allergic to down.

Otherwise even if am 'making money' off selling synthetic for those temps I will usually talk you out of/talk you through it for that middle range quilt and strongly suggest you buy a down quilt from someone else rather than sell you a 25* synthetic.

The only deep winter trip I'd take synthetic would be for a prolonged trek in below freezing conditions which 99.9% of us are unlikely to ever take.

Just Bill,

Thanks for this, an interesting insight.

You say you make primaloft quilts. Where do you get the insulation from might i ask?

Also, how do you go about calculating the loft requirements?

RedKyte

[redkyte510]

The other important thing to note regarding down vs. synthetic is the lifespan of the materials. A properly taken care of down garment (quilt, jacket, etc...) can last decades. Down will not break down (pun intended) through repeated compression cycles like synthetic fibers do. As such, a synthetic quilt will need to be replaced more often than its down counterpart- usage being equivalent between the two.

I'm not saying synthetic is bad at all. In fact, the synthetic insulation most cottage vendors use today is quite good. And companies that produce 100% synthetic items have a great reputation (i.e. Arrowhead Equipment). I prefer down for the smaller pack volume. I also do not add overfill to my quilts- as most cottage manufacturers already overfill their quilts by 15-20%. But if pack volume is of no issue to you, synthetic may be a great option- especially if price is of concern. The counter argument to the price issue is that most vendors now offer budget down quilts that are in the same price-range as a good synthetic quilt.

rweb82,

Another interesting point. I didn't realise that synthetic sleeping bags degrade so...

I've had the same synthetic bag for almost 6 years and I haven't noticed the quality degrading at all.

RedKyte

[Just Bill]

Just Bill,

Thanks for this, an interesting insight.

You say you make primaloft quilts. Where do you get the insulation from might i ask?

Also, how do you go about calculating the loft requirements?

RedKyte

Can't really say what a UK source would be. I buy mine now direct from Primaloft.

I 'do the math' but having done it...
3.0 ounce or 100GSM is 45* when properly quilted.
A double layer of that with offset quilting is 25*

They do sell a 4 ounce/120GSM version too that runs about 40*.

Synthetics go by CLO values, not loft.
That said... the reason you will often hear me argue against using synthetic much past 25* or so is that the math breaks down as you approach zero degrees.
So much so that you almost have to switch back to a loft chart rather than a CLO chart.

With Climbashield Apex... the chart is roughly
2 ounce= 50* (really should be 2.5)
4oz= 40*
6oz= 30*
8oz= 20*

My chart stops there. Enlightened Equipment dropped their zero degree Apex. Though if that was due to lack of performance or the fact they were big enough to fill a medium sized backpack I can't say.
To those that use it... it's a free country. But I would not make, sell or suggest anyone use the stuff at that temp range. If anything... a Hybrid of a 20* down with a 45* synthetic is a nice balance. For folks who are allergic to down... buying a commercially made synthetic sleeping bag is where I suggest they look. Something that has been EN rated and designed for those temps. I have not looked in several years but usually it's not Apex that's in those bags. Taking a quick look at REI:
Big Agnes- Primaloft Black Hi-loft (a continuous filament designed for colder temps)
Mountain Hardware- Thermal Q insulation (a generic hollow fiber fill)

The 3.6 Apex gets you 45* which is the weight I pushed for when I used to use Apex years ago.
Apex has the advantage of being cheap and easy to work with... though technically it should also be quilted 24" OC though no cottage vendor I am aware of follows that spec.

Primaloft Gold is 'Premium Synthetic' and costs more for material and labor. At one point I was the only vendor producing sleeping gear with it for that reason. (May still be).
There are ways to avoid the quilting, but not for a 'registered vendor' like myself. For personal use I have cheated the specs a bit at the expense of durability to produce a few FKT quilts (12 ounce and under).

However give the current extremely low down prices there isn't much reason to produce a $200 premium synthetic when you can buy a good quality down bag for $150.
There is a small niche group of people who have enough understanding of the product to appreciate it... but not enough to justify the costs for me at this time to stick with it. I make a batch of 15-25 a year to sell to existing customers and/or long distance hikers who know about it as I still have some material left. I may look at doing them again but I'm focused on the bridges for the time being... but quilts is actually where I started making gear.

The Hydrophobically treated downs have also hurt synthetic development as that was always a 'concern' with down that helped synthetic grow.
Patagonia remains one of the big pushers of synthetic insulation for apparel so much of the development by Primaloft is in that area...
No complaints from me... but the eco-friendly and high recycled content has been the focus of recent innovation.
The thermaplume insulation is pretty neat, but it will be years before that pans out to something any of us can buy.

So overall... innovation for synthetic sleeping gear is pretty stagnant.
Not much economic interest or consumer demand for it and I'm too small a guy to overcome some of the manufacturing challenges that could make it more readily available.
Though eventually I think the market will support a premium synthetic quilt for summer use, especially in a top quilt.

For DIY... Quest outfitters is the last place in the USA I am aware of. I think RBTR gave up on it.

[Shug]

Down loft chart.
Shug

down loft chart copy.jpg