Author Topic: Sleeping bags: how do they wear out, how long?  (Read 305 times)

Sleeping bags: how do they wear out, how long?
« on: May 16, 2018, 08:22:39 pm »
Do sleeping bags (with synthetic fill) lose their insulating properties over time or use? What's the process, if so? Would this happen without visible wear and tear on the bag?

Reason for asking: I was cold at Long Itchington (and on the way up there and back again)! Thinking it might be a good idea to get a warmer sleeping bag, it seemed a good idea to start by checking what I had. It's a Snugpak Softie 6, which is rated down to zero for comfort with an absolute low of -5. Well it was definitely wasn't near zero on any of those nights. I think it might have gone down to 4 on one night. I was using the bag with a liner (also synthetic) and a decent mat, and it definitely wasn't the mat at fault; I felt cold on top warm underneath me. But I bought this sleeping bag back in 1996. It get used pretty intensively for the first year or so and sporadically since then. It doesn't look worn. But maybe the filling just loses insulating property by being bundled up in a stuff sack for many years? And/or maybe I just feel the cold more than I used to.

Obvious follower: what bags do people recommend? Had a look in Blacks, knowledgeable seeming(?) person reckoned a 3-season bag would be too warm. I'm not so sure!
When the sun is up it is always shining
On cloudy days you see the silver lining

Kim

  • An appetite for the epic, but no real stamina
Re: Sleeping bags: how do they wear out, how long?
« Reply #1 on: May 16, 2018, 08:56:01 pm »
Being stored in the stuff sack probably doesn't help, though I think that's more of a problem for down than synthetic.

How much sleeping bag is enough is going to vary from person to person.  I wouldn't want less than a 3-season bag for BRITISH could-get-down-to-zero-with-a-couple-of-days-notice conditions, though I do sometimes sleep with my feet sticking out the bottom, or with the whole thing unfolded into an awkwardly-shaped quilt if it's warm.  It's much easier to let heat out of a warm sleeping bag than keep heat in a cold one!

I think comfort can vary with age.  I camped happily with a skinny synthetic bag and a closed-cell foam mat when I was a teen, but as an adult I feel the cold.  I also went from being borderline anorexic to the lardy side of healthy in my early 20s, so it's hard to say what had the most effect.
To ride the Windcheetah, first, you must embrace the cantilever...

Basil

  • Um....err......oh bugger!
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Re: Sleeping bags: how do they wear out, how long?
« Reply #2 on: May 16, 2018, 09:28:17 pm »
Being stored in the stuff sack probably doesn't help, though I think that's more of a problem for down than synthetic.

Yes.  I was taught that by the rather keen chappy who sold me my latest.  It now only lives in the stuff sack when actually travelling.  Between times it lives folded in a Ceredigion Council recycling bag on top of the wardrobe.
Sadly, it's been there rather a while recently.
Quote from: Kim
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Re: Sleeping bags: how do they wear out, how long?
« Reply #3 on: May 16, 2018, 09:29:43 pm »
My understanding is that synthetic insulation is made up of long fibers which get broken up into shorter ones with use. This lowers the amount of loft you get, and thus the insulation value. This process can be quite fast - I recall an article on backpackinglight.com where they tested a synthetic puffy jacket and found the loft was considerably reduced after a week of hard use. I'm not sure if storing compressed was meant to be an issue for this as opposed to actual use but it is recommended that you store sleeping bags uncompressed.

Down is meant to be more resistant to this kind of degradation. I think the reason people are more careful storing down is that it's typically more expensive rather than because it's fragile.

You say you bought the bag in 1996. I have a vague feeling that at some point in time, probably after 1996,  those temperature ratings went from 'whatever the manufacturer could get away with' to a more realistic standardized test. You'd need to check, but if you were to buy a new bag you might not want to judge it based on the rating of your old one.

A few other things can have big effects on how cold you are sleeping. If you get in the bag cold it can take hours to warm up. Eating a high-fat meal for dinner helps. Being even very slightly damp has a huge effect. It's also a good idea to fluff up your bag before each use.

Kim

  • An appetite for the epic, but no real stamina
Re: Sleeping bags: how do they wear out, how long?
« Reply #4 on: May 16, 2018, 09:40:06 pm »
A few other things can have big effects on how cold you are sleeping. If you get in the bag cold it can take hours to warm up. Eating a high-fat meal for dinner helps. Being even very slightly damp has a huge effect. It's also a good idea to fluff up your bag before each use.

I've come round to barakta's way of thinking regarding hot water bottles.

If it's even vaguely cold, then I'll have a load of cold arse and hip lard to warm up before I reach equilibrium in my sleeping bag, and until that happens I'll be feeling cold.  My usual technique involves getting into the bag early after a brisk walk to and from the wash block and wriggling around doing Stuff (reading, spodding, plotting routes, whatever) for an hour or so before I do anything that might slow my metabolism like fall asleep or lie still listening to music.  A small hot water bottle (or other water container you trust not to leak) can achieve a similar effect in much less time.
To ride the Windcheetah, first, you must embrace the cantilever...

quixoticgeek

  • Mostly Harmless
Re: Sleeping bags: how do they wear out, how long?
« Reply #5 on: May 16, 2018, 10:42:58 pm »
But maybe the filling just loses insulating property by being bundled up in a stuff sack for many years? And/or maybe I just feel the cold more than I used to.

Obvious follower: what bags do people recommend? Had a look in Blacks, knowledgeable seeming(?) person reckoned a 3-season bag would be too warm. I'm not so sure!

Storing a sleeping bag in a stuff sack is a really good way to shorten it's life. If you want to make a bag last longer, store it uncompressed. A good bag will come with a storage sack. If not, use a large pillow case.

As for recommendations, I like the Mountain equipment Lamina series of bags. I have the Lamina 35 and a Laminina 20. (5°, -7°) bags. I also have an As Tucas Sestrels Quilt for racing.

If you're feeling flush, then Tundra Sleeping bags are lovely, big and warm and down, and light. But you pay for what you get.

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

nicknack

  • Fledgling Swampy
Re: Sleeping bags: how do they wear out, how long?
« Reply #6 on: May 16, 2018, 11:11:49 pm »
I still have the one I had in the Scouts - 50 years ago. Blacks Icelandic I think. Can't remember when I last used it though.
This old man came rolling home.

Re: Sleeping bags: how do they wear out, how long?
« Reply #7 on: May 17, 2018, 08:41:50 am »
Thanks everyone. It seems likely that my sleeping bag is in fact degraded and it's not just me being 22 years older; I guess this is a good thing! And I reckon I'll ignore the recommendation of the woman in Blacks, who probably is 22 years younger than me (and likely wants to get rid of stock I've since found out is specifically made for them despite the Berghaus name) and go for 3-season not 2.5. As for those ratings:
You say you bought the bag in 1996. I have a vague feeling that at some point in time, probably after 1996,  those temperature ratings went from 'whatever the manufacturer could get away with' to a more realistic standardized test. You'd need to check, but if you were to buy a new bag you might not want to judge it based on the rating of your old one.
That's an odd one. The 0C comfort rating is what the manufacturer gives for the same model now, so presumably to ENwhateveritis, though they don't specifically state this so maybe not. Given that I was buying it for a year's "backpacking" in the "Big OE" sense in NZ, I find it curious that I'd have bought something rated down to 0. But I guess I might have reckoned warmer can be made cooler easier than cold can be made warmer, and might have been thinking of Kiwi Alps and things.
When the sun is up it is always shining
On cloudy days you see the silver lining

Re: Sleeping bags: how do they wear out, how long?
« Reply #8 on: May 17, 2018, 09:34:02 am »
The last synthetic bag I had went from being comfortable at -5° outdoors to not warm enough at +5° to +7° indoors over 2 years of frequent use (every weekend, pretty much, in the stuff sack during the weekend, but not otherwise).
Down generally lasts better, but it's still best stored loose.

EN temperature ratings started in 2005, but it took a while before most bags were tested against it.

Re: Sleeping bags: how do they wear out, how long?
« Reply #9 on: May 19, 2018, 08:41:47 pm »
  My usual technique involves getting into the bag early after a brisk walk to and from the wash block and wriggling around doing Stuff (reading, spodding, plotting routes, whatever) for an hour or so before I do anything that might slow my metabolism

Got to ask, what's spodding?

Interesting thread - just bought a factory second Snugpak Softie 9 hawk in fetching black. Functionally fine I think. Have heard some reports that they overstate their bags' temperature abilities. No idea if true. Also bought a softie lite jacket/extra layer and fetching softie hat just in case. Oh and softie tent bootees :)