What size generator do you need? Add running watts, then the largest starting watts.
Running that sump pump from a battery bank instead: what size battery bank for a sump pump backup.
A battery bank stores watt-hours instead of burning fuel. Whether it replaces a generator depends on the daily watt-hours you measured. This page does not publish that comparison in dollars. See what size battery bank for an off-grid cabin and how many batteries you need for van life, plus the battery bank sizing tables.
Add the running watts of the loads you will power at once, then the largest starting watts. This page does not publish a house wattage total.
Add the cabin's running watts and its largest starting watts. This page does not publish a cabin wattage total. Battery-bank sizing for a cabin is on the cabin page.
Floor area is not a wattage. Add the running watts of the loads in that house and the largest starting watts. This page does not publish a wattage for a 2,000 sq ft house.
This page does not publish a refrigerator wattage. The refrigerator battery page is the battery-bank side of that load.
Compare a battery bank with a generator only after you have the daily watt-hours and the seller's prices. This page does not publish those prices.
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Shop gear matched to this page: inverter generators on Amazon · LiFePO4 batteries on Amazon
When the outage is a fridge and a CPAP rather than a generator, the one-day bank is battery backup for a fridge and a CPAP.
References for depth of discharge and cycle life:
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Estimates follow industry-standard sizing rules and common safety margins. Always confirm with a licensed professional for final sizing.
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