The issue is that you will always have the plastic under any new covers and I suspect that the heat will always build up, especially in the weather that we're experiencing at the moment and probably will in most years to come if the trend upwards continues. I don't actually find my plain jane cloth seats (OEM Simora) too bad but I do miss the leather seats in my old Audi Q5 when I''m in the T6 - they're ventilated.