Stacking a -1C and a +10C quilt ok for Overland in May?

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Stacking a -1C and a +10C quilt ok for Overland in May?

Postby bongoman » Wed 03 Apr, 2024 9:02 am

I am walking the Overland Track in late May.

I have a -1C quilt and a +10C quilt and at this stage am carrying both.

According to a formula I found online for calculating the combined temperature rating of two sleeping bags: X - (21-Y)/2

where X is the rating of the thicker bag and Y is the rating of the thinner bag, this gives me a rating for the stacked quilts of -6.5C

Does it sound like a reasonable plan to carry both quilts? I'll be sleeping on a Nemo Tensor pad (uninsulated) and can also pack a silk liner.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby Moondog55 » Wed 03 Apr, 2024 9:45 am

From memory that formula is for Fahrenheit

https://support.enlightenedequipment.co ... ro-camping
I'd reckon that combo good much lower than -1C, probably closer to -10 or -12C
Are both quilts the same insulation? Down or synthetic? If one is synthetic and the other down using the down on the inside gives better results where moisture management is concerned. With suitable clothing I've been able to take my own combination of the S2S 10C Traveller and my Nunatak ~10C overquilt [ 100GSM APEX] down to well below freezing comfortably but that is with a winter rated mattress. I think you should add in a CCF pad if it's going to get cool or buy an insulated mattress. An added CCF pad is the best and cheapest option
Ve are too soon old und too late schmart
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby bongoman » Wed 03 Apr, 2024 10:26 am

Thanks for the reply and advice re also adding a CCF pad or upgrading to a insulated mat.

The +10 C is synthetic, the -1C is down. I guess I also need to be careful about not compressing the down too though if the synthetic bag is on top?
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby crollsurf » Wed 03 Apr, 2024 11:45 am

Stacking definately works but different manufactures use different ratings. Enlightened Equipement isn't a comfort rating. My -6C EE quilt is really only good down to 0C. My 10C synth EE on the other hand is good almost to 10C.

You can also boost the rating by wearing a puffy jacket and pants to bed. Also need to consider whether you are a cold sleeper or not.

Too many variables to say conclusively if that setup will be right for you, but it sounds like you should be OK.

The Nemo Tensor pad doesn't sound like it's up to the task. A combined R rating over 6 would be OK, 7 would be great.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby JohnnoMcJohnno » Wed 03 Apr, 2024 12:47 pm

A couple of thoughts, pretty much what everyone else has said. The stacking formula looks about right provided the quilt and bag temperature ratings are based on the same standard. But the non-insulated mat is a concern. It might be OK if you're staying inside the huts, but those tent platforms get *&%$#! cold. I'd be either upgrading the mat or adding a CCF Pad. You won't get the sleeping bag rating you're hoping for unless the mat is up to scratch.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby craigprice » Thu 04 Apr, 2024 4:31 pm

Here's something else to think about - I never got this concept to work, for me the top quilt always seems to slip off the bottom quilt no matter what I do, unless in a bivy sack. I am what they call an active sleeper ie I turn continually during the night by preference. Ok on the tent floor as it doesn't go far, *&%$#! nuisance on a bench in a hut.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby craigprice » Thu 04 Apr, 2024 4:34 pm

Here's something else to think about - I never got this concept to work, for me the top quilt always seems to slip off the bottom quilt no matter what I do, unless in a bivy sack. I am what they call an active sleeper ie I turn continually during the night by preference. Ok on the tent floor as it doesn't go far, big nuisance on a bench in a hut. My preference is always to use a winter thermarest under and good quality winter/snow rated quilt (and sleep in my own tent not the hut). Extra temp control is better done with thermal underwear/ clothes.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby Moondog55 » Thu 04 Apr, 2024 5:07 pm

Re craigs comment
I have never had the same problem but I did suffer from cold air along the sides. I needed to use an extra tape under the mat to control drafts but problem fixed with an extra large sewn in footbox plus mat sleeve
Ve are too soon old und too late schmart
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby headwerkn » Wed 10 Apr, 2024 12:52 am

I'd be more tempted to use a thermal liner (eg. S2S Thermal Reactor) in conjunction with the -1C quilt, rather than faff with a second quilt (unless it's synthetic and you're using it to manage condensation).

For reference, I used a +5C quilt with a Thermal Reactor liner on an Uberlite mat with a 3mm foam mat underneath in September conditions (snow on Ossa etc). I wore regular 100 weight merino thermal top and bottom, basic bed socks, beany and synthetic hooded puffy, and found that plenty warm.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby Franco » Wed 10 Apr, 2024 8:53 am

Don't forget loose(clean...) socks, a beenie and gloves. Those do make a big difference. As stated by several others, IF the mat is not up to it, you will be cold. I have seen folk cold inside a -12c down bag at around 0c because of sleeping on a 2-3 R mat .
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby myrtlegirl » Wed 10 Apr, 2024 9:21 am

I've been that person with a good bag (-3C) and a poor mat (R2) in about +2C, on a tent platform in calm clear weather. It was awful. The side that was on the mat froze, and ached so badly, and I had to turn all night to defrost it. The non-ground contact side was fine, and I'd naively assumed the warmth would spread down to the other side - nah. It would have been even worse if there had been any wind.


After that, I spent 4 times more on a mat than I'd ever spent, and have never regretted it.
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Re: Stacking a -1C and a +10C quilt ok for Overland in May?

Postby Moondog55 » Wed 10 Apr, 2024 9:57 am

Only took me a decade or so to upgrade to a ThermaRest mat way back when.
But personally I've never found liners add any real warmth boost, they may keep a bag cleaner but the added weight for a thick fleece type thick liner that might add a couple of degrees to a bags warmth is IMO better used as a properly designed overbag or overquiilt.
More so sometimes than going to a heavier and warmer bag;especially if you happen to toss and turn all night like me
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