In spite of claims to the contrary, these sheets are no help at all for anyone who sleeps hot - especially on a memory foam mattress. The fitted sheet, noted as "waterproof," is backed with a thin rubber-like material. How can that help with heat???On the plus side, the top sheet is very thin and silky in texture. The fitted sheet has a very stretchy skirt (the top sleeping surface is backed with the material described above, but the fitting skirt is a different material) and really holds the sheet in place so if you need a sheet that doesn't wrinkle or "crawl," this is, literally, a good fit.The bottom sheet takes about three to four times as long to dry as the top sheet. I guess this is because the fitting skirt is a different material and the backing on the sleeping surface. One has to wonder how long that backing will hold up. Will it crack or crumble like so many waterproofing surfaces? Don't know.So far I have not found any good solution for the problem of sleeping hot on a memory foam mattress. This is one more failed experiment. Now that I've tried it, you won't have to.