I’ve been sleeping on these for about a month. I don’t know if they somehow actively cool, but they are incredibly light and as such don’t seem to retain body heat making them very comfortable for the warm weather months. I’m someone who needs at least a light coverlet for a little weighted feel to sleep, and these are the first sheets I’ve been able to combine with the thin blanket and sleep through the night without kicking them both off. Liked them enough that I just sent a set to a friend as a gift… never done that with SHEETS before!