Depends if you need heating/cooling. Otherwise 500W would cover lights, fridge, TV. So 100kW battery, 200 hours.

Depends on the size of the house's load and the size of the battery and the efficiency of the inverter.

Ford's promo site says 'up to 10 days with rationing power' asuming 30kWh use per day with extended-range battery. But it's not clear to me if 30kWH is normal use, and rationing would be less, or if that's the rationed use. A 300 kWH battery seems rather large to me, and i haven't seen an actual spec for the Ford.

Edit: reread their site after reading sibling posts, in a different blurb they say 3 days or 10 days with rationing with the same assumption about 30 kWH per day; so their rationing assumption must be getting down closer to 9 kWH per day. Either way, a nice feature to have that would eliminate a portable generator for me.

The average household electricity consumption per day is 28.9 kWh. For comparison, the Tesla Model X long range has a battery capacity of 100 kWh.

So in theory, a fully charged Model X could power the average home for 3 days. Really puts into perspective how much energy is needed to move a car at highway speeds.

Ford claims three days based on 30 kwh per day usage.

So the standard "house battery backup" systems are around the 20-30kWH range, and they are good for about 1-2 days depending on your usage.

The F150 Lighting has up to a 150kWH battery, so somewhere in the 1-2 week range, depending on use.

From other reports I've seen claims of three days at "normal" power draw, up to ten days if you're deliberately conserving power.