It also looks like a Powerwall 2 costs about $7,500 plus about another $5K for installation.

I use about 20kWh per day--I have a somewhat smaller house--and vaguely looked into whole house batteries a few months back and concluded they would only make sense if I had it wired into just a few critical systems like my furnace. But, at the end of the day, I should still just get a propane-fueled generator at this point if I ever got anything.

So $2K for a battery that can power a house for a day seems almost an order of magnitude off if they literally mean power an entire normal house.