We sleep on a king-sized Nordic HDM from European Sleepworks (based on researching through this site, have had it about a year and really like it, especially the flexible slat system underneath). My wife ends up sleeping hot despite the latex over coils and is waking up in the middle of the night (she doesn’t start out hot). We don’t currently have another protector on the bed.
I was hoping you could help provide a distinction between the St. Dormeir mattress protector and the 45th Street Bedding Washable Wool Mattress Pad. I read through some of the other threads so it seems like one of those options might be good for us, but I wasn’t sure how we should interpret the difference in fill (4.5 oz/yd vs. 10 oz/yd). Will one be better at temperature regulation? Is one more likely to cause a difference in the feel of the mattress (and if that’s the case would we likely be able to make up for the difference by adjusting the slats)? Or is there another approach you’d recommend?
While it’s not possible to quantify the effect on sleeping temperature of any component for any particular person because there are so many variables involved and there is no standardized testing for this … there is more about tracking down a potential cause or causes of any temperature regulation issues your wife may be having (at least to the degree possible) in post #2 here that may be helpful.
Since it would be unusual to have temperature regulation issues on a mattress that used latex on top of a microcoil (which is very breathable) and that had a wool quilted cover … I would probably start with your sheets and your bedding/blankets and/or your bedclothes because synthetic fabrics will tend to sleep warmer than natural fabrics. Changing the temperature of the room would also be worth considering.
I would also keep in mind that wool is more “temperature neutral” rather than “cool” so for some people thicker layers of wool may still be warmer than they prefer.
In terms of the differences between the two protectors … while I don’t have any personal experience with them I would guess that the 45th street bedding would have a greater effect on neutralizing temperature swings (in both directions) because of the greater amount of wool but it would also have a bigger effect on the compression and contouring and on the “feel” of the comfort layers in the mattress underneath it.
Since a mattress protector will affect the feel and performance of the upper layers more than the deeper layers … I don’t think that changes in the tension adjustable foundation would have a significant effect in “offsetting” the effect of the mattress protector.