Upper limits of sleeping bags

Discussion in 'Sleeping Bags & Quilts' started by Zequico, Sep 23, 2020.

  1. Zequico

    Zequico Day Walker

    Hi guys! This is my first post on the forum, and I have a question about the upper limits of sleeping bags. I'm looking for a sleeping bag, but I can't decide between aegismax nano-L (574g, comfort: 10 °C) and nano 2(M:624g or L:742g, comfort: 5 °C and looks to have a better construction). I will use it mainly in the summer in Portugal, where the temperature is well above the comfort temperature of both bags(>15ºC). I'm also planning to buy a silk liner for warmer nights. Maybe, I will try to sleep on it during the winter in the south of Portugal, with night temperatures of 9-10C. So, how many degrees above the temperature rating, according to your experience, can you sleep comfortably before you start sweating? And what sleeping bag do you recommend me to buy?

    Sorry for my English.
    Marco likes this.
  2. Foxster

    Foxster Section Hiker

    Forget the rating numbers, they are made up by the makers to sell bags.

    Instead multiply the amount of fill by its fill power. Compare the result between bags. It won't give a perfect comparison because there's a bit more to a bag than just these two numbers but it will be a damned sight better than rating numbers.
    Zequico likes this.
  3. dovidola

    dovidola Thru Hiker

    What @Foxster said. Plus, if still in doubt, go for the warmer one.
    Zequico likes this.
  4. Stube

    Stube Summit Camper

    Welcome to the forum Zequico - your English is excellent by the way.
    This is a difficult question as it depends on whether you are a hot or cold sleeper.
    I sleep hot and often use just a silk liner to sleep in Southern England summers. (12+ degC}
    I would find either of your bags too warm even for winter sleeping.
    I would go for the cooler bag and silk liner to save weight and give flexibility.
    If the bag has a full length zip you could also use it as a quilt in summer it's cooler.
    Marco and Zequico like this.
  5. Henry

    Henry Ultralighter

    I’ve got the nano2. I was warm at 5-10 degrees with a decent mat and leggings T-shirt combo, no hat, arms out of bag.

    Id be getting pretty hot at 15 degrees plus; but sleep experience can be a very personal thing; (I think I’m pretty average).

    The nano 2 zip is not full length so you can’t turn it into a quilt style if you’re too hot. For me it’s too warm for those summer temps, fine for the winter ones. I slept at near freezing in it; that’s about it’s limit for me.
    Zequico likes this.
  6. Zequico

    Zequico Day Walker

    Thank you all for your advice. I will buy the nano.
  7. JRT

    JRT Backpacker

    Hiking in Italy in summer 2018 - it was about 25-30°C during the day and dropped to around 15-20° at night. Probably similar temps to Portugal. I slept with just my S2S Thermalite XL liner and was fine, still too warm even. I found it to be very good at wicking the sweat out and it weighs bugger all.
    Zequico likes this.
  8. Marco

    Marco Ultralighter

    It depends on the brand. Some brands (mostly the cheaper ones) clearly make up the temperature ratings, as well as the compressed volumes. However, serious brands try to offer good values: there is no point (from a serious brand viewpoint) to sell bags if your customers are not happy with them.

    That said, even the EN standard for temperature ratings is quite inaccurate. Testing the same bag in different labs can show ratings as different as more than 5 ºC.
    Last edited: Sep 27, 2020
    Zequico and Mole like this.
  9. Marco

    Marco Ultralighter

    Good point. The key to extend the comfort range of a bag towards the warm side is ventilation. A full zip works much better than a half zip. And a quilt even better than a bag ;)
    Zequico likes this.
  10. Foxster

    Foxster Section Hiker

    I wasn't aware of the inaccuracies in testing and that may partially explain some of the inconsistencies I've seen, but not all.

    I don't have the numbers to hand at the moment but a while ago when I was last buying a winter bag I found major issues with the ratings of some big-brand bags. This was not the first time I'd seen this.

    For instance, I was comparing two top-line bags. One was rated at 10°C colder than the other and yet had less fill and lower fill-power than the other. Now I appreciate that construction of baffles and such contributes to a warmer bag but surely not enough to overcome such obvious factors as the fill to such a large degree.

    Then there is the inconsistencies with the ratings used. Some quote a single number, like -5°C, some two different comfort ratings without explaining what they are, some make their own up rating.

    So, until the makers get their act together, I maintain that the temperature rating are useful only as a very broad system to identify bags as, say, a winter versus a summer bag. After that they are best ignored and the fill amount and fill power are more useful. Though, of course, I suspect that there is a bit of "creativity" with those numbers too.
    Zequico likes this.

Share This Page