just a few miles from Charlie Lindbergh's farm, and a little ways south of Brainerd (remember the movie _Fargo_?), and there is a major climatological boundary in the 150 miles between there and the much warmer area (!) you'll be in, but I remember well the block heater ritual on our cars and the big Minneapolis-Moline diesel tractor with the snowplow in the shed. The car and the pick-up were always both Ford gas-burners but had 750 or 1000 watt tank (spliced into a heater hose) or block heaters with automatic thermostats and when both of them were plugged in, they kept the interior of the garage, which was an insulated addition on the northwest (windward in a blizzard) side of the house above freezing even when it was below zero outside -- esentially we were using the vehicles' motors as space heater radiators. That made everything easy to start and comfy to drive off in, and probably didn't raise the overall utility bill all that much because it protected the house walls from some radiant losses. Besides, farmers were allowed separate electric meters with cheaper rates for such essential business uses in those days.

The big M-M tractor was in an insulated machine shed with woodstove available, and had a huge 1750 watt, 220 volt tank heater with its own pulse-type circulating pump and thermostat, and that also kept the whole shed quite warm, in spite of there being a lot of air leaks around the big door, etc. The tractor was straight ether starting, no glowplugs, but it was never a problem to get it running when needed -- the bigger problem was busting through the snowbank which formed in front of the door without sliding sideways and damaging the building.

At St. Cloud State College and many shopping center and factory parking lots up there they have long had parking meters with an extra coin slot and a plug socket so that for an extra quarter you can get two hours of heat from your block heater!

One of my uncles was for 50 years or so one of the township snowplow operators, and I never heard of him ever having any trouble starting his big CAT 12E grader, either. On the other hand, when the local high school switched to diesel school buses, they eventually had to build a garage, but only because the kids would sneak out late at night and unplug the block heater extension cords when the buses were parked out of doors.