Do you have a mattress protector on your bed? Is it made of vinyl or shower curtain type material? If so, switch to a natural fiber one (we use the My Green Mattress organic cotton). A synthetic mattress protector will trap heat and make you hotter. We have a Woolino wool duvet insert with a linen duvet cover, organic cotton sheets, and a Faribault Mill wool blanket if we need an extra layer on cooler nights. Our bed is sooo comfy and cozy, not too hot or cold. Natural fibers are key! A set of cotton sheets and a wool blanket should be a good combo. Everyone thinks of wool as a cold/winter fabric but it’s good year round, a chameleon of sorts. More on reddit.com

I was also sleeping hot and made some significant changes to my bed. I love my memory mattress just for the comfort. So, I bought a wool mattress topper, cotton percale sheets, a silk duvet and use either a cotton or cotton/linen duvet cover. We also have a wool duvet that my husband seems to like more than the silk but doesn’t really care. I truly believe that using natural instead of synthetic materials has made a huge difference. More on reddit.com

Twice in the last 6 years I've ordered 400 thread count sheet off of Amazon and within a few years they ripped. Bottom sheet just ripped down the middle. I have sheets that are 75 years old that my grandmother embroidery that I'm still using that are in great shape so I was kind of done with buying cheap sheets. Target recently had a sale on a thousand thread count sheets for only a little over $100 and I will tell you that they are absolutely heavenly. They're so thick that I can only drive one sheet at a time in the dryer and sinking into them at night is absolutely heavenly. More on reddit.com

Take the duvet off the bed and just use sheets in the summer. There's no such thing as a not hot duvet, that's the point of the duvet. It might take a few tries to get used to it but I promise you a human being can sleep just fine under only a sheet. Air is the insulator, not the material the sheet or duvet is made out of. Materials that trap air within them give a layer of insulation that is proportional to how much air they trap. A thick ass duvet is going to make you hot, doesn't matter if it's coated in silk or cotton. Down is hot because the little feather fluffs are evolutionarily designed to trap as much air as possible with as little material as possible. It's not intrinsic to the materials feathers are made of. Silk can be just as hot as cotton if the weave is tight and the threads are as heavy, but usually it's a looser weave of thinner threads. If you want more weight on top of you (I hate it but whatever) just get a weighted blanket. You can't have a big fluffy duvet on top of you and be cool. That's just thermodynamics. More on reddit.com