I just bought a Sealy Hope Mills mattress and I've been sleeping too warm.   I have never had such a problem before.  The mattress is in the same room as my previous and the room temperature is the same. 

I'd like to change it for another Sealy mattress as firm as possible.  I'm considering the Bryant Park or the Eaglewood Cushion Firm because they don't have memory foam on top, which I have been told is the material that causes to sweat at night.  The Stonedge could be another option but I believe it has memory foam on top.  Any suggestions on what might be the firmest and coolest?

I appreciate your input.  Thank you in advance.