said by TheMG:Ventless heaters also exist, Some that do not require any power all.
I would consider alternatives for emergency heat. Perhaps one of those propane or kerosene heaters that vent through the wall (often called "direct vent" heaters).
Reason being that the efficiency of the generator in turning fuel to electricity is very low, much less than 50%. This means most of the fuel the generator burns is heating the outdoors, and not the house.
Then you could use the extra capacity to power other things, instead of blowing it all on electric heaters.
Anyways, just an idea.