I worked as a tech and had to wear a polyester lab coat and I couldn't do it. I have hot flashes and the polyester held the heat in. I roasted. I quit the job just because I couldn't stand being overheated and sweating all the time. For a quilt, maybe it will keep you really warm. I use cotton because that's what I was taught and I'm a good girl and do what I'm told (when it comes to quilting only) ha ha