Ive been trying to learn how to calculate the clo value in a down jacket.
I dont need 100% spot on value but if i could get within ~0.3 clo of the actual clo value
then i would be happy. I think i got a way to do it but im not sure if its the right way.
Here is how i do it with the numbers for 800fp down:
Patagonia Fitz Roy Hoody:
Richard.N says that it has a clo value of 3.94.
ive read that it has 181grams of down.
800fp down is 45.93g/1,62oz/clo in densitys betwen 1,62oz/yd2/in3 and 4,05oz/yd2/in3.
181/45.93 = Clo 3,94.
Eddie Bauer peak XV:
Richard.N says that it has a clo value of 7.47.
Here is how i do it: 12,76 oz/361,7g of down and 2.5inch loft.
361.7/2,5 = 144,7g/inch of loft. 147,7-115 = 29,7. 29,7/5,11 = 5,81.
1,0581*45,93 = 48,59. 361,7/48,59 = clo7,44.
Not 100% spot on but close enough for me, could be that i use 800fp numbers and the jacket has 850fp.
Feathered friends Rock and Ice parka:
Richard.N says it has a clo value of 11,98
Here is how i do it:
size M = 582g of down. im guessing it has 4" baffle height from pictures ive seen.
582/4 = 145,5. 145,5-115= 30,5. 30,5/5,11=5,96.
1,0596*45,93 = 48,66. 582/48,66 = clo 11,96.
Again close but not 100%
Using this method seems to work just fine, but i only know this because i can compare my results to Richard's results. I own a Wolff-Wear -50 Expedition jacket, it has 800g(!) of 800fp down in size M, 4" baffles.
800/4 = 200. 200-115 = 85. 85/5,11= 16,6.
1,166*45,93= 53,55. 800/53,55 = Clo 14,93.
Can someone tell me if a clo value of 14,93 seems reasonable for this jacket?
Sorry for my bad english but i hope you can understand.