Hi Rosie,
This thread is fine
The better options and possibilities I’m aware of in the Greater Vancouver area are listed in post #2 here.
You can read about some of the factors that can affect sleeping temperature in post #2 here. Soft foam materials where you sink in more deeply and that don’t have some type of breathable cover or material over them or that use a mattress protector or sheets over them than don’t ventilate or wick moisture well can be more insulating and sleep warmer than firmer materials or materials that breathe and wick moisture more effectively. In other words … it may have been the type of polyurethane in combination with the other materials that were in or over your sleeping system rather than just the polyurethane itself.
Phoenix