They say these are cooler and may be, but being 100% rayon, they stretch way too much and bunch together. If you like to make the bed nice and taught, the top sheet will hang down far on one side. They are extremely soft--I'll give them that. My big pet peave is that Tempur Pedic took away the two different color straps and instead added a tag that says "bottom" in the middle of the sheet. My wife sewed two pieces of fabric around the straps so that we know which are which. Really Tempur Pedic, the colored straps were one of the best things you ever did. Neither of us ever questioned which were the top/bottom of our king sheets. I'll pay the extra few dollars. Bring them back or perhaps even flip over the strap so one set is black and one is white. Next purchase will probably be at a Tempur-Pedic store so we can feel the sheets.