solar + storage + water sheath fireplace can run pretty much till you run out of wood.
But yes, unless you spend serious money (own sewer, water from underground etc), it's basically solution for "the power pole is down", not any grid wide problems.
I mean "run out of wood" is the problem though. There aren't that many trees, certainly not enough for everyone in a region to start doing it.
You'd be better off with an air sourced hear pump for hot water anyway - the one in my house uses less power then my dehumidifier.
> unless you spend serious money (own sewer, water from underground etc)
It is often the case (at least where I live) that having a septic system and well is far more economical than obtaining a property with access to city utilities.