Two notes: in a modern insulated home in not so cold climate 1kW absorbed is enough to heat a home with -20℃ outside, with is still far more than a simple fan but a power level a classic small generator can provide. The second note is that if you get gas from pipes the supplier need electricity to pump it, so it might have autonomous power or not, you can't be sure.
As a safeguard I prefer a classic wood burning stove, witch is far from being comfy but works alone, reliably and I can stock enough woods or emergency source it almost anywhere...
Living in the French Alps I do not know much about New England homes (insulation, ventilation, power system, ...) but IME gas heating systems are in the mean LESS reliable than heat pumps and electricity + wood is the combo to be comfy normally and backed up in case of trouble.
