I have a block heater. But, when it is 10F out, it only gets my engine to about 80F. Still takes 4-5mins to get to 161F, where I can get into EV mode and turn on the heater. Of course, once I'm in EV mode, the engine begins to cool again. When it drops below 161F, my ICE turns on... Vicious cycle.
__________________
|