You wouldn't use it to heat your entire home...just use it as a supplemental heat source for the areas you're in the most. Keep the thermostat at 66? and use the heater in the room(s) you're in.
Use your ceiling fan on low blowing upwards to keep the warm air moving.
I have a Gen 3 and love it! It's built to use in a 1000 sq foot area. We did the math and, based on what the utility company charges us for therms and the number of therms they say it uses, we pay about .18 an hour to run it on high. Ahhhhem.....I'm worth .18 an hour :)