I really would like to hear BPL's official response to Richard's issue (that BPL is still endorsing or at least suggesting the use of loft as a measurement of warmth - not to mention the inconsistent measurements).
This has been bugging me lately in just about every BPL review that involves insulation.
IMO, BPL should *only* be publishing measured thermal resistance in sleeping bags and clothing, and *not* mention loft at all. I know many will disagree here, but unfortunately if you are using loft to gauge how warm something will be, you are being led astray.
As an example, my first thought on reading this would be "hey, the Mont-Bell has more loft, is lighter, and cheaper - I should get that instead."
But both the inconsistent loft measurements by BPL as well as the unsuitability of using it as a measurement of warmth means that the Mont-Bell jacket may not actually be warmer. It could be not as warm, in fact.
I'm glad that at least relative warmth has been measured in some capacity, but nothing is shown to compare it to. If it's because you're just starting to measure this now and in the future, and don't have any other measurements on other products, fine, but at least delete the "measured loft" section on the table, because it will mislead people into thinking that those numbers are the ones to use for comparing the warmth of these garments.
As for Mike's comment - there is so much information here in the BPL forums which disproves "warmth is subjective." I suppose that the times which you *feel* warm are subjective in part, but insulation value is completely measurable. Additionally, and more importantly, subjective statements of warmth during whatever activity in whatever temperature have shown to be almost entirely meaningless. You don't know what the person's thermal output is (very small changes in activity can change this a large amount), how the wind is affecting things, what the sky temperature and radiation losses are, how much moisture is currently on - and evaporating from - the person's skin, what the humidity level is, if the person was slightly hypo- or hyperthermic for a period of time before the evaluation, etc. A small change in any one of these can mean the difference between "feels nice and warm" and "I was cold."