> A properly insulated house in any temperate climate require very little heating or cooling.

A "properly insulated" house still requires something around 0,5 W/m2/K. Modeling a moderate 120 m2 house in the coldest months when the temperatures hit 15-20 negative you still need 2,5 kW of heat with domestic hot water on top. Put in the efficiency of a heat pump and you are still easily looking at half a mega watt-hour per month. ~1MWh for a whole house is very reasonable number during winter months, sans electric mobility.

That's entirely unrealistic to cover with batteries with current battery technologies alone, electricity generation is absolutely REQUIRED. Windmills can help soften the blow and storage needs substantially, but the TFA is about solar, which is effectively absent during the winter.