Try putting a multimeter on it to measure the resistance. I'll go do mine right now and you can compare...
OK, I'm back! Man it's cold out.
I read 16.4 ohms at the plugs/prongs of the heater cord.
Which is roughly what is should be,
according to this calculator: Enter 110 volts, 16.4 ohms and hit "calculate" = 737 watts. @ 115v = 806 Watts.
Mine's a 800w nominal heater.
Ohms Law Calculator