This is Exped's warmest mat (R factor of 10, compared to the pathetic 8 of their Downmat 9 LW
) Wider and thicker, true, but also 900 grams heavier! It's semi-self-inflating (open the inflation valve, leave for 10 minutes, then finish off with a few breaths of air into valve)
I've used this a few times, and by gum, its warm and comfy! However, last weekend I thought I'd try it with the ultralite mesh cot I have (Luxurylite). Lots of snow and sub-zero temps. Trouble was, the cot wasn't flat - on a slight sideways slope, so the Comfort tended to slide off it. So I completely deflated the mat so that it would contour to the cot, relying just on the foam interior to provide insulation under my sleeping bag (the mesh cover on the cot provided no barrier at all to cold air under the cot). Not only did I sleep right through the night - without any late night "comfort" visits to the tree-line - but when I did wake up I could feel heat radiating off the mat upwards into the bag.
I'm not sure if the down bag would have worked as well, I'm guessing that my weight would have compressed the down insulation in a deflated downmat so much that its insulating properties would be lost. Down relies on loft for its heat retentrion properties, and doesn't do well when heavily compressed. Might be worth considering the Exped Sim range, as at least you would retain insulating properties if the bag developed a leak, as well as a degree (if significantly lesser) from the foam.
) Wider and thicker, true, but also 900 grams heavier! It's semi-self-inflating (open the inflation valve, leave for 10 minutes, then finish off with a few breaths of air into valve)I've used this a few times, and by gum, its warm and comfy! However, last weekend I thought I'd try it with the ultralite mesh cot I have (Luxurylite). Lots of snow and sub-zero temps. Trouble was, the cot wasn't flat - on a slight sideways slope, so the Comfort tended to slide off it. So I completely deflated the mat so that it would contour to the cot, relying just on the foam interior to provide insulation under my sleeping bag (the mesh cover on the cot provided no barrier at all to cold air under the cot). Not only did I sleep right through the night - without any late night "comfort" visits to the tree-line - but when I did wake up I could feel heat radiating off the mat upwards into the bag.
I'm not sure if the down bag would have worked as well, I'm guessing that my weight would have compressed the down insulation in a deflated downmat so much that its insulating properties would be lost. Down relies on loft for its heat retentrion properties, and doesn't do well when heavily compressed. Might be worth considering the Exped Sim range, as at least you would retain insulating properties if the bag developed a leak, as well as a degree (if significantly lesser) from the foam.
