How Did They Do That Anyway?

It was cold last night. To say "very cold" is simply not descriptive enough. Both our remote thermometers showed 10 degrees below zero. That's 42 degrees below freezing. That's 82 degrees below our daytime comfort level. At night we turn the thermostat down to 65 degrees but that still means the furnace has to heat the house 75 degrees above the outdoor temp. That is Cooooooold. How did our grandparents survive their pioneer years in sod houses or in their first wood homes with no insulation? And how did the Native Americans survive the winters when cold spells far exceeded what we are currently experiencing! I'm grateful for a good furnace. Still....that kind of cold tends to put a nagging fear in me that is relieved when weather brings warmer days.