Hi JenHans,
As you’re a warm sleeper, the only areas where I would expect you to sweat would be where you were in contact with your sleeping surface, as that is where you would be “insulated”. I don’t know what you’re using for your sheets and mattress pad/protector, and that is where I would begin analyzing, as in very general terms, the materials, layers, and components of a sleeping system that are closer to your skin will have a bigger effect on airflow, moisture transport, and temperature regulation than materials, layers, and components that are further away from your skin and softer mattresses will tend to be more “insulating” and for some people can sleep warmer than firmer versions of the same material.
As far as materials and heat in a mattress, I can’t comment better than what I did in one of my earlier replies to you in this thread: There is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range. There’s a lot of good information in that post about sheets, mattress protectors, natural fibers and temperature regulation.
The KISS mattress uses latex over memory foam over a polyfoam core, so while using very breathable material on top, and as you already mentioned you are a warm sleeper, it’s possible you may desire something using more resilient and breathable materials in all of your comfort layers (perhaps no memory foam) or using innersprings instead of a polyfoam core. But I would still address first what you’re using for your top-of-mattress products, as those can have a dramatic impact upon your sleeping “microclimate”. If you’re sleeping too warm on a product like this (Talalay latex is more breathable than memory foam), switching to a memory foam mattress would more than likely have you sleeping warmer than what you are right now. How much you “sink into” the mattress will also have an impact upon your sleeping temperature. Sinking in more to a mattress exposes less of your surface area for heat exchange and also insulates your body more.
While I can’t diagnose comfort issues via an online forum due to the myriad of variables involved (both personal and from the mattress), there is some information about the many different symptoms that people may experience on a mattress and some of the most common causes behind them in post #2 here that may be helpful. If you think you need more plushness with this particular mattress, you certainly could add some sort of a topper, and Talalay latex would be preferable (there are even some microcoil toppers now available), but the concern I would have would be you sinking in even more, which would further insulate you and could cause you to sleep even warmer. This is why I would first address your mattress pad/protector/sheets to see if you can find any issues there to help you sleep more comfortably. If you can address that and decide to keep this mattress, then you might wish to investigate a topper. But if this mattress unfortunately doesn’t work out for you as well as you would have hoped, you at least have a good trial policy and you can return it and you probably wouldn’t want to be purchasing toppers for a product that you may not be keeping.
From a distance, this is about the best I can do with your questions. I’ll be interested in learning about any top-of-mattress changes that you might be able to make and see if they have any impact upon your sleeping environment.
Phoenix