We live in a 900 sq ft house. We only use one window AC to keep the bedroom cool, though it actually does very well keeping the whole house at about 70. We just don't get very hot here in summer normally, and AC is uncommon here. The AC doesn't actually kick on very much. I use fans as much as possible to keep it comfortable. I use natural light as much as possible, but have thermal curtains on the windows that are closed if the sun in coming in during the summer. That helps keep it cooler.
We use an efficient wood stove for heat. It only takes us about a cord and a half of wood for a year, since we like it about 60-62 in the bedroom.
We've been changing over light bulbs to LEDs slowly, and lights are kept off if not in use. So that helps on power use. The appliances we picked out are all low on power use.
It's also just the two of us, which helps keep it low. Interestingly, our power use dropped considerably when we moved here from the apartment we lived in, even though the space was same size. The apartments were build in the mid 1990s and the house is 1900. There isn't any insulation in the walls, but there is a good amount in the attic and the vinyl siding, which has a foam under insulation, was put on over the old shakes. So the places is actually well insulated.
We ran about $120 a month at the apartment.
