Hi I live in Quebec city, it's not Siberia nor Alaska but we do have low temperature for weeks in a row. "the battery warmer only works when plugged" : on page 365 of owner manual, they say that the charge indicator blinks once after staying on for a few seconds when the battery has been fully charged and the battery heating system has been activated. I observed that behavior last winter and the "on - blinking" occurs only once in a while, so it looks like the battery heater is not constantly on. The heater "draws a small amount of power" : I didn't have to shut off the charger when the kitchen oven was on as they were both on the same circuit (don't be scared, the situation has been corrected). Last winter, the car never failed to start when left unpluged for the night at minus 25 celsius. I agree that this stuff is not highly scientific, but many aspects of the Clarity are in that "flou artistique".