People lived in the north prior to the invention of electricity, so it's possible. Maybe more difficult now due to the quantity of firewood that would be needed with a larger population? Architecture (and dense urban development) plays an important role in electricity-free livability across various climate conditions. Some buildings work well in the cold, some work well in the heat. That's not to say you as an individual can address these problems, but society as a whole can design urban systems which support low-energy living in even difficult conditions.