In a recent study, researchers from the European Environmental Bureau (EEB), the Stockholm School of Economics (SSE), and the Potsdam Institute for Climate Impact Research (PIK) questioned the planned development of new nuclear capacities in the energy strategies of the United States and certain European countries.
This has been done for close to a century in wind or run of river hydro heavy countries (as well as some coal ones).
The water heater has a buffer tank and is attached to a meter that only runs when a signal is sent across the power line. This stores about 20kWh for a 300L tank.
Modern insulation would allow going up to a few m^3 for a couple weeks’ worth.
Combine that with some radiant floor heating on a nice thick concrete slab and you could use the battery for home heating. (Though it would need a lot of water.)