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One more question.... When bags have a listed loft is it measured by laying the sleeping bag on the ground and measuring how high it "puffs up" or by how much insulation you will have around you when laying in it. If the latter, wouldn't it mean you really only have half the loft insulating you since your laying on the other half. So when you lay on your side the other 3" will loft back up and insulate you back? Or does it mean that is how much insulation is between you and the cold air outside. So when you measure your loft it should actually be around double what is listed? Which I would doubt or I got screwed on my bags loft. <img src="/forums/images/graemlins/frown.gif" alt="" />


Usually, a bag's "loft" refers to the overall loft, from the ground to the top of the bag. Sometimes you'll see the term, "top loft," which means just that, the thickness of just the top portion of the bag. So, a bag with 5" of loft puts about 2.5" of insulation between you and the outside air.

There are some bags that have the down distributed other than half & half. I have an old Trailwise bag that has 60 percent of the down on top, and 40 percent on the bottom. It has a side block baffle to prevent the down from shifting. This is probably more likely found on cold-weather bags these days.