Maybe I'm being a bit dim here, but how can you tell if the down is lofting properly and not lying flattened along the bottom of each tube?

The destructions tell you to get the down out of the ends if it's become compressed there by tapping it when it's part-inflated. I assumed mine was lofting proberly because it felt a lot warmer to lie on than my Airic.

Hmmm... not quite the confidence-inspiring answer that I was hoping for, but thanks all the same, Kate.

Destructions? Please tell me you meant instructions!

My downmat is very warm so I'd recommend going for a nice lie down and seeing how warm it feels.