You can power all those gas appliances with a reasonably-sized generator, though. It's also possible to run a heat pump on a generator, but you'd need a much bigger generator and a soft-start for the heat pump to limit starting current.
You wouldn't even need that. The electricity usage of gas appliance is miniscule as it's usually just to automatically light the pilot or vent. An 100Wh battery could probably power everything for a week or longer.
Good point, although ideally the house would be wired to make it easy to connect that battery to just the gas appliances so that other stuff (lights, fans, refrigerator, etc.) wouldn't drain it much sooner.
Personally, I'd rather have the generator if I had the space, but this would be a good option for people in townhouses and condos.
