Recent sleep system testing

In a recent post, I shared some ideas on how to sleep soundly in the outdoors. Today’s post will cover some specific sleeping equipment testing I did recently.

Last fall, I reviewed the model 65 Swiss army sleeping bag which I have been using for the past 2 years. In that review, I mentioned how the older Swiss sleep system consisted of the sleeping bag, an inner fleece liner and a bivy bag. I wrote that I did not have the additional components, but planned to reconstruct the system using similar ones. Here’s the sleeping bag, with a picture of the bivy below it. I don’t have a picture of the cheap summer mummy bag I’m using as the liner.

Then, on New Year’s Day, I gave an account of new items I received or purchased for Christmas, where I showed you the two faux lamb fleeces I sewed together to form a “bushcrafty-looking” sleeping pad for cool and cold weather.

I decided to take advantage of some recent colder weather (for southern Finland, at least) to test both the reconstructed Swiss system (outfitted with an additional layer, in other words, there were two liners) and the fleece sleeping pad. It’s important to note that this testing was carried out using a mishmash of older/surplus/unique equipment I happen to have, rather than new, off-the-shelf sleeping equipment currently in production. As such, it shouldn’t be seen as a suggestion for a specific setup to be copied. Rather, see it as just one example of what can be used. Maybe it can give you a rough idea of how similar items would work together for you.

Conditions: According to the weather report , the temperature was to range from -20 to -28*C (-4 to -18.5*F) during the night of testing. Since I don’t plan on sleeping outdoors at temperatures much below -30*C (-22*F), I thought this would be a good opportunity to test the limits of all the components of my sleep system combined. Seeing as how I live in a city and didn’t have enough time or daylight to get out into the country, I decided to do my testing outside on the terrace, which was covered with compacted snow. There was a continual breeze in the air, and the temperature upon starting my test was -21*C (-6*F).

Equipment: Nested from the outside in:

  • A waterproof Italian mil. surp. bivy bag, unzipped
  • A Swiss mil. surp. sleeping bag (with a comfort rating of roughly 2*C (35*F) without the fleece liner)
  • A no-name el-cheapo mummy bag (with a comfort rating of 10*C (50*F))
  • A Freetime Micropak 1400 mummy bag (with a comfort rating of 3*C (37.5*F) and an extreme rating of -12*C (10.5*F))

Also:

  • Two thin foam sleeping pads, 5 mm (0.2″) each (they were under the sleeping bags, but inside the bivy bag
  • Faux lamb fleece on top of the foam pads
  • Clothing: thin and thick long underwear, fleece jacket, gloves, balaclava and two pair of thick knit wool socks over thin hiking socks

I didn’t bother weighing this equipment, but roughly knowing the individual item weights I estimate it to be about 5 – 6 kg (11 – 13 lbs.), not including the clothing. I know, I know. One good winter sleeping bag, bivy bag and sleeping pad would weigh a fraction of that. What can I say, I have an aversion to buying new stuff if I already have equipment that works, even if it weighs more.

Test: I slipped into my nest-o-bags at about 10:30 p.m. and promptly fell asleep. The plan was to sleep the whole night outside. I decided to end the test when I woke up at 1 a.m., though not because I was cold, or even cool, in any way. I felt so warm, in fact, that I suspected that the temperature had risen dramatically over the time I had slept. I checked the temperature: still -21*C (-6*F). The reason I woke up was because I was snoring so loudly! I tend to snore when sleeping on my back on the ground. 🙂

Results: Over the past few years, I have suffered through enough uncomfortable nights at a wide range of conditions in different sleep systems to know when something works or not. So although I only slept for 2.5 hours, which is a far cry from a full night’s sleep, the fact that I woke up very comfortably warm indicated to me that I should have been fine all night, at least at that temperature (based on past experience, I would have woken up sooner if I were too cold; since body heat output drops while sleeping, there’s a significant difference between being awake and asleep in a sleeping bag). The fact that I was still so warm leads me to assume that this particular setup would be reasonably comfortable down to -25*C (-13*F), at least. Further testing will say whether this is the case, because that is always the only way to know for sure. So I’m planning on testing it at -25*C (-13*F) and -30*C (-22*F) for a full night. By the way, the temperature ended up hovering around -21*C (-6*F) all night, so no insight into heat retention at lower temperatures would have been gained by staying out the rest of the night. As for the faux lamb fleece sleeping pad, I was very surprised at how well it worked! It provided plenty of cushioning and was very warm as well. Not bad for 30 Euro ($40 US) and a few minutes of sewing!

Now that I have established what works well for me toward the colder end of the spectrum (in my particular case), I can experiment with different setups for warmer temperatures, i.e. leaving out this bag or that bag to fine-tune the comfort level. This weekend I will test the bivy, Swiss bag, liner bag, i.e. as close to the original Swiss sleep system as I can get (which, by the way, cost me about 33 Euro ($43 US) altogether), plus the pads underneath (I’ll leave out the innermost sleeping bag mentioned above). The temperature is expected to be about -7*C (19.5*F), so it’ll be a decent test for that setup.

When testing sleeping equipment like this at lower temperatures, it’s a good idea to either carry out your testing near a place where you can “escape” to if you get too cold or otherwise bring an extra sleeping bag or two just in case. One time a few years back, I actually had to leave my camp in the middle of the night and hike to the cabin nearby because I was too cold. Not fun. Just be smart about where you do your testing, considering the potential danger/discomfort involved!!!

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11 comments on “Recent sleep system testing

  1. Ron says:

    There you have it; you don’t need a multihundred dollar, highbrand sleepingbag to stay comfy.
    A bit of thinking ahead, some ingenuity and problemsolving thinking will get you a long way. Who cares about the weight? I wonder who will be hiking 25km at a temperature of -25C, without the use of a pulka, sled or toboggan. I know I must certainly would not!
    Now all you need is to tackle the snoring…. if that even wakes you up… than it must be some solid hardwoodsawing you were doing! 😉

  2. wgiles says:

    I have spent cold nights in several different sleeping bags. One thing that strikes me is that a fleece liner appears to make a big difference in my perceived comfort level. I have one of the Swiss army fleece liners, but I haven’t used it yet. It is much thicker than the ones that I normally use. My warmest bag is my 40 year old down bag and my second warmest is a Therma-Nest tapered bag that I got around ten years ago. I have several Eureka 30F bags that I got cheap and keep in the vehicles for emergencies. I have slept in these and been plenty cold on a night that didn’t get to freezing. I have some 0F rated bags that were also cold on a 30F night on a cot pad. I stuck a fleece liner in the bag and was fine. I don’t trust the ratings. I think that the only true test is to try the bag(s) yourself and decide, like you did.

    • Right you are, a sleeping bag liner can definitely go a long way! I bet a lot of folks would save a good deal of money if they nested bags instead of buying new bags with a lower rating, which, as you mentioned, can’t always be trusted.

      Thanks for the comments!

  3. I agree- sometimes I wonder what the field tester was wearing when they temperature rated the sleeping bag.

  4. Dan says:

    Great review I seen your 1st review of the swiss army bag, do you no anyone in the uk that sells them; none on ebay to? atb dan

    • Thanks! Don’t know offhand of which shops carry it in the UK, but I’d check the big ones first. Mr. Google would also probably be able to help. 🙂

      • danny says:

        I just got 4 bags and 2 liners only, for the family on camo trips, I got just 1 bag and had to get more, very very impressed, ive had british army summer bag, austrian sniper bag, german one similier to swiss but no hood, I had dutch arctic m80 and brit arctic. I must say im chuffed to bits, in arctic I use 2 swiss bags n 1 blue fleece liner, autumn just 1 bag n one line. Summer just liner or swiss on its own. Never had a bag so roomy to. The material is silent also at night. This is thebest. Love the hood to, thanks to your reviews tho mate, atb Danny

  5. danny says:

    I just got 4 bags and 2 liners only, for the family on camo trips, I got just 1 bag and had to get more, very very impressed, ive had british army summer bag, austrian sniper bag, german one similier to swiss but no hood, I had dutch arctic m80 and brit arctic. I must say im chuffed to bits, in arctic I use 2 swiss bags n 1 blue fleece liner, autumn just 1 bag n one line. Summer just liner or swiss on its own. Never had a bag so roomy to. The material is silent also at night. This is thebest. Love the hood to, thanks to your reviews tho mate, atb Danny

    • Thanks for the comments, Danny! I think I’ll keep my Swiss bag until it falls apart. 🙂 My “nesting formula” for the different seasons is very similar to yours. Also totally agree re: the roominess, material silence, hood etc. etc. etc. A great bag all around!

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