Yes it gets cold here, and i have had a few power outages. 6 people a year, on average, crash right in front of our house, and there is a powerline that keeps getting knocked down. Last week it was around -45 and i think i killed my heater, it was 250W in a 55 gallon tank. was on all the time i think it burned out, or wasnt strong enough to heat my tank so i ordered a new heater off the net. the biggest heater at my lfs was a 150W, my 250W couldnt keep it up to 70 degrees, which is really cold, so i put a blanket over the tank, heated water, siphoned it under my filter intake tube, and once a long time ago, i had to take one of those mini bbq gas powered grills, put a metal bucket on it, and siphon water into the bucket from the tank, and have a pump run water back up into my tank and under the filter intake tube from the bucket. but that was when it got really cold out. we also have a wood stove, and generally dont heat our house with anything else.