I have been trying out how to boost the warmth of my mat as looking to buy a new wider mat but keep it light and not to carry a heavy/warm one when not needed. I normally open my bags like a quilt. I have been trying to create warmth using a lifesystem emergency blanket. Tests was done using an Multi mat 25mm inflatable foam mattress. The bag is a mammut +4 comfort rating. https://www.ultralightoutdoorgear.c...survive-outdoors-longer-emergency-blanket-p14 First I laid the mat on top of the blanket and nothing happened. Second attempt I laid the blanket over my mat and slipped inside the bag and it become very snug. Then I wrapped the remainder of the blanket over the top of the bag and become too warm. With all the tests I was only in the bag for 10 minuets. Unsure but maybe to try 2 blankets which will be very warm and a Klymit V2 which in this set up should be ok to maybe 0degrees, but certainly worth a try.