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  1. #1
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    Top quilt as bottom quilt: Enlightened Revelation

    I've used my Revelation 20 deg top quilt for five nights in temps down to 45. It's very warm, too hot really in anything above 50 deg without venting.

    I've been maxing out my thinlite under-insulation at these temps. So, last night I hooked the up the Revelation as an underquilt. I used four bungee cords to attach the corners up to prussiks on my ridgeline. Works great! Coverage above the head to below the toes (I'm 5'9" tall). Very warm at 44 degrees. My cold spot area measured 85 degrees, which is just two or three degrees below "toasty". Top insulation was a 25 degree synth bag used as a quilt.

    I guess this thing does it all!

  2. #2
    Senior Member BillyBob58's Avatar
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    Quote Originally Posted by dakine View Post
    I've used my Revelation 20 deg top quilt for five nights in temps down to 45. It's very warm, too hot really in anything above 50 deg without venting.

    I've been maxing out my thinlite under-insulation at these temps. So, last night I hooked the up the Revelation as an underquilt. I used four bungee cords to attach the corners up to prussiks on my ridgeline. Works great! Coverage above the head to below the toes (I'm 5'9" tall). Very warm at 44 degrees. My cold spot area measured 85 degrees, which is just two or three degrees below "toasty". Top insulation was a 25 degree synth bag used as a quilt.

    I guess this thing does it all!
    Interesting! Can you say more about what you mean when you say "My cold spot area measured 85 degrees, which is just two or three degrees below "toasty"" ?

  3. #3
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    Quote Originally Posted by BillyBob58 View Post
    Interesting! Can you say more about what you mean when you say "My cold spot area measured 85 degrees, which is just two or three degrees below "toasty"" ?
    Sure, I use a thermometer under my back. 87 degrees is a normal daytime reading. So I call this "toasty" warm at night. When the under-temperature drops to 80 degrees I begin to feel a cold spot.

    I've been doing this awhile to gauge various types of insulation. For example, 1/4 inch thinlinte provides an 18 degree boost in ambient temp. So for me it's good down to about 62 degrees when I start feeling a cold spot. For camping, cold spots are not a big deal so I can go a bit lower. I haven't measured the "shivering" temperature yet

    The 20 deg quilt I used last night provided a 40 degree boost in temperature, from 45 ambient, to 85 under by back.

  4. #4
    Senior Member BillyBob58's Avatar
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    Quote Originally Posted by dakine View Post
    Sure, I use a thermometer under my back. 87 degrees is a normal daytime reading. So I call this "toasty" warm at night. When the under-temperature drops to 80 degrees I begin to feel a cold spot.

    I've been doing this awhile to gauge various types of insulation. For example, 1/4 inch thinlinte provides an 18 degree boost in ambient temp. So for me it's good down to about 62 degrees when I start feeling a cold spot. For camping, cold spots are not a big deal so I can go a bit lower. I haven't measured the "shivering" temperature yet

    The 20 deg quilt I used last night provided a 40 degree boost in temperature, from 45 ambient, to 85 under by back.
    OK, thx, I thought that might be what you were referring to. I have seen that approach mentioned before, but rarely. Looks like a good means of testing to get an idea of what will work before the actual cold temps get here. Is the thermometer right under your back, or between the hammock and the UQ? What kind of thermometer do you use?

    I think someone once said that the temp between their back and their recliner was about like 85F in a warm house, and considered toasty warm.

    I'm fascinated by your test results. For example, most folks seem to need insulation below 70F in order to stay asleep, some more like 75, some maybe even 80?

    So you get an 18F boost from 1/4" CCF, and you just start to feel a cold spot at 62F. So for me, starting from needing nothing above 70F ( assuming wind is totally blocked), I would think 70-18= 52. But for you it is 62, so maybe that means you start to need insulation below 80F?

    Based on that, would that mean the 20F quilt, which gave you a 40F boost, would be good for you to 80F-40F= 40F? Or am I trying to read way to much precision into your results? ( plus there are so many variables, like drafts and gaps and wind and then the personal variables like how tired or well fed or already cold you are) Then again, people do vary a whole lot, and there are a few folks here who would never be warm enough at 20 in a 20 rated UQ, and some only to 40, so maybe it is an accurate assumption?

    Then another thing I wonder about: how well would making these tests in warm weather apply to the real world in cold weather? ( although I guess you have been measuring with the temps in the 40s?) IOW, will there be any difference in the rate of transfer of heat if the differential between skin and ambient temp is greater? IOW, if you get an 18* boost testing at say, 60F ambient, do you still get an 18F boost testing at 30F? I think probably yes, 18* of protection is 18* of protection regardless of ambient temp, but I am not sure.

    Any way, interesting tests, do some more!

  5. #5
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    I'm not an expert in homeostatsis, and I only have a few data points to work with. Maybe by the end of winter I can publish a graph or two. But in my area the temps rarely get below 30 degrees.

    I have a cheap plastic thermometer right under my back. I only take the temperature after a full night outdoors, so temps are stabilized.

    I suspect that, around 87 degree ambient temperature, there is no warming effect from under-insulation. The body probably releases heat elsewhere. So, the boost in temperature I measure approaches zero as the ambient temperature approaches 87. If I use a pad at 87 degrees, I would not expect my back to be 87+18=105 deg.

    Similarly, the 40 degree boost from the underquilt may increase to 50 degree boost or more at lower temperatures. This is because my body may have been releasing excess heat. As ambient temps reduce, I would expect the boost to increase to its actual value, then remain there.

    I suppose after all this we could have a chart showing under-temperature as a function of ambient temperature and insulation type. 87 degrees is toasty warm, 80 is cold spots, etc down to shivering.

  6. #6
    Senior Member BillyBob58's Avatar
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    Quote Originally Posted by dakine View Post
    ...............

    I suspect that, around 87 degree ambient temperature, there is no warming effect from under-insulation. The body probably releases heat elsewhere. So, the boost in temperature I measure approaches zero as the ambient temperature approaches 87. If I use a pad at 87 degrees, I would not expect my back to be 87+18=105 deg.

    Similarly, the 40 degree boost from the underquilt may increase to 50 degree boost or more at lower temperatures. This is because my body may have been releasing excess heat. As ambient temps reduce, I would expect the boost to increase to its actual value, then remain there.

    I suppose after all this we could have a chart showing under-temperature as a function of ambient temperature and insulation type. 87 degrees is toasty warm, 80 is cold spots, etc down to shivering.
    Good points, may be on to something there. Then again, if I am laying on a pad at 85 or 90F, I really would expect my back to be quite hot, uncomfortably so. And sweating to boot. Probably even if I had an UQ under me, but it might not be as obvious. Anyway, I'm glad you have been measuring this and I need to do some of this myself!

  7. #7
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    20 deg top quilt hung as underquilt


  8. #8
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    Awesome! Thanks for sharing

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