^^^
I'm curious about those temperatures, as well. I posted some pix upstream of the temperature of my SEATING SURFACE. Maybe these temps refer to the maximum temperature of the HEAT COIL?
If you've ever taken apart a seat heater and looked at them, the wires are very thin. Something on the order of 22-24 gauge, or finer. (That way they heat up with lower current more than a thicker wire would need.)
I have not been in sub-zero temps with my truck yet. But, having complained about what I perceived as low temps on my seat, the more I use them, the more I've found that 1 bar is fine. I'll start with 3 bar, and drop it to 1 bar within about 10 minutes or so.
My dream? I'm in arctic-like cold and I come out to my truck, frozen in a block of frozen precip, the cold air slicing into my lungs with each breath. I climb into the seat and start it up (which it does right away
): yeah, it's freezing inside the cab. One push of the ol' three-bar seat heater, and in about 30 seconds I'm cocooned in warmth from the bottom and back of the seat. Oh, -23F outside? And the truck sat all night? Huh. Getting a bit warm from the seat, may have to crack a window...