Hi again!
I would be surprised if the wool is the culprit in your sleeping hot. Wool is among the best temperature regulating materials … and in combination with cotton which wicks moisture into the wool has one of the best effects on cooling. I would also keep in mind that wool regulates temperature in both directions (it’s used in the desert and also in cold climates because of this) so while it may not feel “cool” … it generally doesn’t feel “hot” either and it also helps to regulate the moisture (which can trap heat) and reduce the perception of temperature that comes from higher humidity levels (similar to how temperatures feel cooler on less humid days than they do on more humid days). It’s interesting to note that perspiration itself is a form of phase change cooling as moisture changes from a liquid into a vapor and absorbs temperature and takes some of the heat away as it disperses. So each layer in a mattress can either add to or detract from the other layers that are involved in the microclimate and their ability to ventilate (add to the dispersal of heat and water vapor) as well as wick moisture and store moisture away from the body is all part of the puzzle.
The fact that removing your previous mattress protector helped reduce the heat leads me to believe this may be more related to the cover materials - Layers that are closer to the top sleeping surface will have the greatest impact upon comfort and sleeping temperature (including any mattress pad, sheets, and linen). I am not sure if you have already read some of our posts that discuss temperature regulations issues, but you can read more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here more about tracking mattress temperature regulation issues potential causes ~ Post #2 here (at least to the degree possible for a specific mattress) and the posts it links to that may be helpful.
Latex and cotton are both breathable, temperature regulating materials that would be a good option for a topper. If changing your protector and bedding doesn’t resolve the heat issue and before buying a latex topper, I’d test this combination first by opening your zipper and putting some cotton over the existing latex to see if it makes any difference. I’d also be careful with adding 2" more thickness to your bed as this may impact your spinal alignment and cause back pains down the road. Another temperature-related factor that I’d look at is … how deep of a cradle you sleep in. The deeper you sink … the more body heat is “trapped” under you regardless of the materials used.
Let us know how all these small changes pan out.
Phoenix
@lorim … Have you ever tried alpaca wool & silk products next to your skin? You can read a bit more about Alpaca fiber vs Wool fiber here