What we mean by "it depends" is what is the makeup of the cover, quilting foam, FR solution or fiber used in the cover on top of the latex. Most latex is constructed with air holes sometimes call pincore. This allows air to travel through the latex allowing surface heat to dissipate from the sleeper’s skin surface. Most urethane foams particularly memory foam will trap heat to a greater degree than latex. There is some latex sold without pincore holes in it, in this case these mattresses will sleep hotter.
Natural latex generally will sleep cooler due to the fact that being natural it captures less ambient heating or cooling. However most all synthetic latex has pincore holes in it as well, making it more breathable. Blended latex either Talalay or Dunlop performs pretty much the same with perhaps slightly better results than all synthetic. Most blended latex will consist of approximately 70-80% synthetic latex (SBR) with the balance being natural latex rubber.
As we have mentioned before, pure wool works as a great thermal asset to latex mattresses. Wool wicks skin surface perspiration away from the body, leaving the skin dry thus cooler in the summer and warmer in the winter. Wool builds a microclimate that is very conducive for your body to naturally air condition itself. The fabric or ticking as we call it in the mattress industry is also a crucial factor to contributing to heating and cooling. There are also fabrics made of synthetic yarn that are specifically engineered for the cooling such as Cool Max, Thermic, Phase Change etc.
Generally latex does not sleep hot. Just be aware of the factors that we have mentioned above, and you should sleep cool on your new latex mattress.
Finally, the top of bed, like pillows, sheets, comforters, etc., is an often-overlooked part of the equation as to why people sleep hot in bed.
There are a few factors contributing the warmth, but changing these will make some improvements, but will not eliminate the issue.
First, while the waterproof mattress protector is an excellent choice and works for most people and doesn't cause a problem heat wise, it is less breathable than say a washable wool mattress protector. We think that the waterproof one is a better solution, but for those suffering high sweats, other options may need to be explored.
Second, a comforter, like a duvet cover, can be contributing to the problem, too. When using a duvet or heavy comforter, you have multiple layers of fabric that can help retain body heat. Another way to think of it is in colder weather, we put layers on to keep warm.
Third, for those that sleep hot, there are other sheet options to help keep you cooler like those that you a phase change material like Outlast. Unfortunately, we am not well versed in this so I cannot give you good recommendation.
While these recommendations can mitigate the issue, it will not completely eliminate it. In our experience, the ChiliPad works the best, but does have some drawbacks like it uses a fan to cool the water in the pad so the fan kicks on and off during the night.
