Increasing fp and dwindling returns

[TeeDee]

Thank for your thoughts youngblood.

I've come to belief that it's not a matter of "things not making sense when they should" but rather that the data I want just not available since all of the testing has been focused on a different paradigm, that of the manufacturers than a DIYer.

Also, I'm still unsure if my original thoughts on the insulating properties of higher fp are incorrect since the data isn't available to confirm or deny. Is the better temp rating of higher fp due to better insulative properties or to more loft of the 1 oz measured? Also, not really too sure of the influence of "feathers" on insulation value because of the lack of data. Also, in the pics I have seen of the "feathers" in down, they are entirely different to flight feathers which and are designed for an entirely different function. Closer to "down" than to flight feathers.

If you compare 1 oz of 800 fp against 1 oz of 900 fp, what is the cause of the difference? Greater loft, hence greater hindrance to convection and/or conduction or something else? Most of this is just unknown, but some of the data that I saw on the BPL thread still seem to indicate that a lower fp, although heavier, may actually provide better insulation. It is still not clear if that is actually true, but the empirical evidence seems to point that it might be. So do you opt for heavy, but warmer, or lighter, costier and maybe colder??? Don't really know if the conclusions are true or false yet.

Since I had already made the choice for the higher fp due to Ed's generous offer, I got lighter and about the same cost. But I am still not too sure about the "theoretical" temp rating on the quilts I made. The loft is enough that I may not be able to test the temp rating, but I would still like to really know. Just curiouser and curiouser.

But then a little knowledge is dangerous, a lot of knowledge is downright fatal.

[BillyBob58]

.............. a lower fp, although heavier, may actually provide better insulation. It is still not clear if that is actually true, but the empirical evidence seems to point that it might be. So do you opt for heavy, but warmer, or lighter, costier and maybe colder??? Don't really know if the conclusions are true or false yet.

Since I had already made the choice for the higher fp due to Ed's generous offer, I got lighter and about the same cost. But I am still not too sure about the "theoretical" temp rating on the quilts I made. The loft is enough that I may not be able to test the temp rating, but I would still like to really know. Just curiouser and curiouser.

But then a little knowledge is dangerous, a lot of knowledge is downright fatal.

If you had some of that 900 fp left over, then what you need is to make a summer-fall rated quilt. If you have any older gear around, say a 25 or 30 degree 650 FP of X loft, make your 900 FP test quilt of the same loft. Then compare on a day with an appropriate temp. If you can account for all the other variables somehow( baffle height and number of/distance between baffles, etc), you might be able to tell if the 900 FP quilt is as warm as the lower FP of the same loft. I imagine it would be easier to compare if there was as much dif as possible, like 550 to 900. ( you might could even rig some sort of hot plate or freezer testing to help eliminate weather variables. Using much smaller, more easily produced quilts. If you couldn't tell much dif either way even between 900 and much lower, then there is probably no dif worth mentioning.

Of course, that would be a lot of trouble, both the production and the testing. Then again, you would then be the original published researcher on the subject.