This mattres protector is actually breathable and cool. I used it for the first time and did not get too warm at all. My mattress top is bamboo, and is extremely soft. With this protector it is a little less soft because of the waterproof material. However, I don't think you can get away from that with a mattress protector of you want it to be water proof. This is an excellent choice! The last one I bought must have been polyester because it was so hot to sleep on. I love this one! Highly recommend.