Perhaps you should also consider what kind of mattress you have.
If like me you have a box mattress with a thinner separate mattress that goes on top of it, check what it is made of. Mine was made of foam rubber, which I found too warm, even although I am rarely too hot at night, or at any other time.
Creating a through draugth by having a bedroom window even very sligthly open, as well as a window at the other side of the storey your bedroom is on open, will make your bedroom cooler.
Finally, which way do your bedroom windows face? Mine are due west, so rollling the blinds down at about two in the afternoon, just as the sun is getting round there, really helps.
I know this has nothing to do with bedding, but all of these tricks are inexpensive, so if you have not already tried them, they are a good place to start.