I use a dyna-glo kerosene heater with white kerosene (no odor). I used these after Hurricane Irene and then Hurricane Sandy and her 11 day aftermath without power.
They can go against a wall and one actually heated our whole house, but I use two of them set on low to balance the temperature of the home. On cold days I even put one in the basement when I am working down there.
Dyna-Glow 10,000 BTU Heater