Do yourself a favor, look at power consumption of your house. These “electric backups” are normally 100ish ah at 12v or 1200watt total. Your refrigerator uses that in a couple hours. Then what?

If you look at off grid systems, they are 10-20x the capacity of these little portable power packs, and have 1500-5000w solar arrays to replenish them.

At the VERY Cheapest using old school SLA batteries to power a house for a day your looking at $1200 in batteries, some complex wiring, and a weight of 1000lb. Add to that chargers and stuff as batteries do not stay charged they must be maintained it’s just a bad idea.

Get a gas generator, 4 stroke. Get an electrician to install it. Grab 4 or 5 Jerry cans, and call it a day. It will be more reliable, cheaper, and not dependent on the sun to replenish it which generally when the power is out is t reliably uncovered.