Using two down bags

Discussion in 'Sleeping Bags & Quilts' started by Diddi, Sep 24, 2018.

  1. Enzo

    Enzo Thru Hiker

    The heuristic I use is to note the number of degrees bellow 20c the bags are rated at and sum them. Apex 67 is ~11, so 9 plus my 400g quilt say -4 so 24 +11= -15. In practice I wouldn't take it past -10.
    Very tempted to combine rsbtr new 7d and see if I can get ~200g of 900+FP down to make a cutting edge stitch thru liner bag. Though I have a cumulus 150 quilt 370g so probably only 100g to be saved.
  2. ZenTrekker

    ZenTrekker Section Hiker

    I don't combine bags to save weight, I do it to save money!
    Diddi likes this.
  3. Diddi

    Diddi Thru Hiker

    And its the same reason i wanted to know if it would work.
    Cant justify forking out hundreds of pounds if i have the kit already gone are those day :bag: :angelic:.
    Weight has never bothered me either on my back as i class it as training :)..
    Great info on the clips etc thanks :thumbsup:
  4. ZenTrekker

    ZenTrekker Section Hiker

    If you go for the 'button-hole' elastic option, just stitch them together so you form a loop that will fit around your sleeping pad. Then you just button-in the toggles wherever you want i.e. you can have the quilt tight (close together or looser (further apart). I use 3 x elastic loops because I have three attachment points each side on my Cumulus quilt. I tend to only attach one side of the quilt, so I can get in and out easily. If it gets cold, then I do them up on both sides.

    Hope that helps, Phil
  5. KVerb

    KVerb Trail Blazer

    I've used my Aegismax quilt on top of my Aegismax G1 at -7°C. Was toasty all through the night, but in the morning the quilt was pretty damp and collapsed, luckily it was just a one-nighter because I didn't have the chance to dry it out due to rain. I'm hoping to make a synthetic overquilt someday to avoid the down collapse.
    Enzo likes this.
  6. Nevis

    Nevis Section Hiker

    In the winter i use an EE Revelation quilt with a modded Costco quilt over it, i just hemmed the bottom of the quilt and put a draw cord through and four kamsnaps up the back. It works most times but does occasionally slip off the EE during the night, have had no issues with being too warm or cold or any dampness.
  7. oreocereus

    oreocereus Thru Hiker

    Out of curiosity, why do you have two of the same bags? Maybe you could sell one and get a more suitable bag/quilt for layering and more versatility - ie something lighter and synthetic which could be used for summer as well, being synthetic will be a more optimal layering solution, more likely to not be “too” warm (2x 400down bags seems very very warm). And it would probably work out cheaper, as synthetic quilts are much more budget friendly, even after the sale of your second bag.

    But maybe your second bag is a family members or a friends?
    Diddi likes this.
  8. KVerb

    KVerb Trail Blazer

    I have to say it was very misty and rainy the whole night. Good to know that it probably won't happen as badly in dryer weather.
  9. Diddi

    Diddi Thru Hiker

    The other bag is for the Misses as she likes to camp with me in warmer times..
    Have two synthetic bags but a tad heavy compared to the pd400's
    oreocereus likes this.
  10. Piiber Teravhammas

    Piiber Teravhammas Trail Blazer

    I have used Malachowski 300 UL II (rated 1C for men) and Cumulus Xlite 200 (I think my version was rated at 10C) together at -12. I slept like a baby.
    I think I have used my Malachowski down to -3 - (-4) with Aklima woolnet long underwear.
  11. fluffkitten

    fluffkitten Moderator Staff Member

    If I manage to get out this winter I'll be using my two sewn through Aegismax bags together, the M2 inside/under the E. Bit weighty and not something for the Cairngorms but plenty warm enough for anywhere I'm likely to go.
  12. Clare

    Clare Thru Hiker

    My EE quilt has those buckles at the mid points and Kam Snaps at neck and above the footboy. I first thought of putting the female/male equivalents on my soon to be acquired overquilt (thanks @Enzo) but because the male Kam faces inwards not outwards, it will be a mild fiddle to connect it all up, Wrong way round Kam then buckle, then buckle, then wrong way round Kam etc

    A simpler plan, following from William's larks foot idea, is to larks foot a tab of grossgrain with velcro on it into each of the existing tab loops that already house the Kam clips and the buckles on my quilt. Then, put equivalent tabs and velcro on the over quilt. That way I don't have to mod (spoil) my quilt and the velcro fastening in the dark and rain will be easy. I can add velcro tabs to the overquilt I am getting from Enzo, or to a poncho from As Tucas if I get one, or to a dust sheet overbag which I'm going to make soon and they will all connect to my quilt easy peasy and interchangeably. No damage will be done to my quilt in the performance of this idea.
    WilliamC likes this.
  13. Enzo

    Enzo Thru Hiker

    You too can look this cool @Clare ! Lol
    That said a useful thermal addition round camp.
    Dave V, gixer, Clare and 1 other person like this.
  14. Clare

    Clare Thru Hiker

    @Enzo I just can't wait, you look angelic. There is a strange open/cool area between waist and knees.

    My sewing machine has gone off to be mended, so this and the dust sheet project on hold for a little while.
  15. Enzo

    Enzo Thru Hiker

    Poor lighting, the footbox end goes down your front and the head end over your head and buckles around in front of your thighs so the open area actually has 130g of apex.
  16. Chiseller

    Chiseller Thru Hiker

    I have used my bpl apex summer quilt inside my golite ultra3 in winter. It worked very well. I had the apex inside as the golite has a very moisture resistant footbox and piece along the neck for breath condensation.
    Ill try it the other way round for fit and function this year if it gets cold enough.
    Ive slept below zero a few times in just the golite and base layer so id only pack them both on well below zero sleeps.
  17. DuneElliot

    DuneElliot Section Hiker this get up how are the ladies not banging your door down?
  18. Enzo

    Enzo Thru Hiker

    That's why I selling it, I value my marriage!
    Balagan, Diddi and FOX160 like this.
  19. Adventurer

    Adventurer Day Walker

    I’ve not long bought a cumulus 350 quilt 2018 version. Went out not long ago and it was quite frosty. Very impressed with the bag.
    Bought it from

    My twitter pics of it in use

    However for the colder weather I’m going to try the cumulus quilt with my PHD filler/liner K series bag. Not sure what that would get me down to in temp but PHD say it’s gets you down another 10 degree. So that would be -8 comfort, does that sound about right?

    I’ve also got a zipless PHD lightweight bag that’s around 700g that’s supposed to go down to -5, and does it? No I’m freezing..... I think I’m a cold sleeper. To be honest I prefer the cumulus quilt to my PHD sleeping bag.
  20. ZenTrekker

    ZenTrekker Section Hiker

    I bought one of these to go with my Cumulus Quilt 350

    Haven't had a chance to use it yet but I reckon it should be OK down to -10˚C in combination with the 350 quilt and a good sleeping mat (154,00 EUR)
  21. Bob-W

    Bob-W Trail Blazer

    I've a PHD Minim 200 bag (I got it in one of their sales - it's in the upcoming March 2019 sale as well), rated to +6C and a Cumulus 150 quilt rated to +4C. Either is fine from late spring to autumn, in summer I use one and my wife the other. Once it gets colder I'll combine them, quilt over the bag, and have used this combo down to -6C and been comfy. Don't worry, my wife doesn't sit there shivering, she has a Cumulus 350 for the cooler nights :)

    There's a formula to work out the comfort temperature of any bag/quilt based on the loft. Note that loft is loft so it works for down and synthetic bags. Loft is also "additive" so you can use the formula for combinations. Let the bag/quilt fully loft then measure its depth in centimetres. You want the depth of a single layer so for a sleeping bag without a zip you divide that figure by two. For zipped bags and quilts open them out then measure. Add the depth of the two bags to get total loft. The formula is:

    Temp in Celsius = 17.5 - (3.5 * Loft)

    5cm of loft equates to zero Celsius, drop 3.5C for every extra centimetre of loft.

    As someone noted above, having a synthetic bag/quilt as the outer means that hopefully the dew point is located in that layer
  22. Michael_x

    Michael_x Section Hiker

    Just wondering if a formula for two sleeping bags, where half the loft of each is squashed flat below you, is valid for bag +quilt.

    With bag plus quilt half the bag loft is lost but all the quilt loft is still above you with none squashed.

    So in theory bag + quilt ought to work out as warmer.

  23. Bob-W

    Bob-W Trail Blazer

    You just want the distance between you and the outside, that's the loft which is why I said to divide the height of an unzippered sleeping bag by two so that the layer under you is discounted.

    So sleeping bag measures 5cm but that's top and bottom, divide by two (assuming the top and bottom have equal fill of course) to give 2.5cm. Quilt measures 3cm but it's just one layer so no need to modify it. Add the two together => 5.5cm and plug in to formula:

    C = 17.5 - (3.5 * 5.5) = -1.75C

    Hopefully that's clearer.
  24. cathyjc

    cathyjc Thru Hiker

    Much too reductive. I'd freeze if I followed that formula.

    I use a Cumulus ~500gms fill (450 + I added some extra down in the top) for 3 season and can take it down to 0C , just o_O.
    The loft of both top+ bottom is 5.5" (=14cms) but as it's differential fill the top is probably nearer 9/10cms.
    By your calculation I should be able to go down to somewhere between -14 and -17 C :nailbiting::roflmao::roflmao::roflmao::roflmao::roflmao:.

    PS. I actually think it's dangerous quoting such a formula. Anyone who is new to this "game" who followed it could be badly caught out when they found the SB they had bought (spent a lot of money??) just didn't keep them warm enough. And that could be somewhere they couldn't get back to "civilisation" :wideyed::(.
    Last edited: Mar 15, 2019
  25. ZenTrekker

    ZenTrekker Section Hiker

    I agree about using formulae @cathyjc because there are too many other variables, your sleeping mat, what you are wearing, what you have had for dinner and how warm or cold a sleeper you are.

    I have a cumulus 350 quilt 2018 version, so 150grams less down than your '450'. I have slept comfortably down to -1˚C with a summer inflatable mat. I wasn't roasting hot neither was I cold, just about right. I wouldn't want to go lower with this combo though.

    Might be worth reading this article
    cathyjc likes this.

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