Originally Posted by cinnamon
I have a diy TQ, and UQ of 5 oz apex and have had it down to the upper 30's. and at those temps the TQ was plenty warm and I could probably push it down to below freezing, but was at the the lower limit for the UQ. personally I sleep rather cold.
Ha, it's funny how things work out for different folks. Partially trying to explain my surprisingly good results with a mere 2.5 oz ( literally: I had about 1 sq.yd. of CS XP under me in a short WB Yeti style UQ) insulation, I had theorized that I might not get results quite so good in a TQ, especially compared to down, because the UQ might not drape on and around me as well as down. As opposed to my dif cut UQ, which is pulled snugly against my back and around my shoulders. So I thought maybe I might not be quite as warm on top with a given wt of TQ compared to my UQ, just due to fit and drape. But for you it was just the opposite! Now I have to come up with another theory!

Originally Posted by FLRider
The formula for figuring temperature ratings from CLO values is as follows:

84 - (14 * CLO * X), where the final result is in degrees F, CLO is the CLO value of the material and X is the weight of the insulation in oz/sq yd. Note that this assumes no base layer worn (if there is a full base layer, change the 84* to 70*)

So, for Climashield APEX (CLO value 0.82, per Thru-Hiker), the value would be:

84 - (14 * 0.82 * X)
= 84 - (11.48 * X)

So, 2.5 oz:

84 - (11.48 * 2.5)
= 84 - 28.7
= 55.3*

5 oz:

84 - (11.48 * 5)
= 84 - 57.4
= 26.6* F

7.5 oz:

84 - (11.48 * 7.5)
= 84 - 86.1
= -2.1* F

10 oz:

84 - (11.48 * 10)
= 84 - 114.8
= -30.8* F

Now, below freezing, these calculations break down some. Since moisture accumulation through condensation, as well as drafts, become much more important when the outside temperature is 70*+ different from your skin temperature, the insulation you're using has to be much better fitted than at warmer temperatures. Figure these as "ballpark" temperatures, assuming a "normal" sleeper, perfect humidity, no drafts, and no wind.

Figure on them being within 10* of comfort and you should be pretty close. Hope it helps!
Good to see a formula like this, even if I am at least somewhat surprised by the results at both extremes! So apparently the idea is that 1 CLO is 14*f worth of protection? What is the starting figure of 84 based on?

So I have been warm with 2.5 XP ( CLO .82 per oz), in a WB torso UQ, car camping between 46-49 and 95-98% humidity per nearby weather stations, right next to a lake, no warm base layers. ( https://www.hammockforums.net/forum/...ad.php?t=11090 ) though I was def warm and might could have got a few more degrees. But in order to have some slack built in for field conditions, I decided per this quote from the thread: "So, I think I can safely say that this ~9.5 oz synthetic torso quilt will be bombproof, all by itself, for 55 plus, pretty safe in the field for 50 or maybe even 45( especially with warm sleep clothes like fleece)." According to your formula, 2.5=55, and I said bombproof to 55. So I guess that is right close!

Cannibal has reported using 10 osy CS XP at a bit above zero ( in the snow with no tarp!), at minus 11F and some colder temp of maybe ~ minus 20F? And I think he was always warm enough, if mem serves(no doubt with plenty of base layers plus he sleeps real hot apparently). So maybe the minus 30.8F with 10 oz from your formula is really not all that far off at least for some people?

All of which I really find quite amazing, whether with 2.5 oz or 10 oz per sq.yd. I mean really, can anyone get much warmer with that amount of insulation, or a torso quilt of that total weight ( maybe 18 to 20 oz?). Maybe, a little, but that is still awfully good! CS is great stuff as long as you have room for it.