I don't have an accurate thermometer, but I just wanted to say:

I got back from a very long trip (four legs, total driving time approx 20 hours), and I had the empeg running the whole time with Mlord's high-temp warning active. I was running the heater in the car (and the vents run fairly close to the empeg). It never got hot enough to trigger the alarm. I was actually quite happy about that.