I know this thread is about insoles, but I just wanted to share my own experience. I picked these boots up from Salomon several week ago, and even with the -20 F and near -50 wind chills that the polar vortex brought us in Wisconsin, I haven't even come close to experiencing cold feet. I've been using them when riding my fat bike. I believe Salomon uses Aerogel in not only the insoles, but also the boot's upper.