You can buy 256Wh battery banks for around $150 now. You can pair them with a timer for charging/topping off at night when electricity is cheap. They even accept solar input.
Throw one in every room and between appliances like the fridge or oven. Now you have a UPS for your whole house and the cheapest energy rates throughout the day.
Do those have an inverter built in? If not, at $600/kWh very pricy compared to what this guy used at $190/kWh for batteries, or $360/kWh including the inverter:
If is he talking power bank, then big ones, usually called power stations, have inverters. But they can’t be used as UPS since they cut power when switching sources.
Throw one in every room and between appliances like the fridge or oven. Now you have a UPS for your whole house and the cheapest energy rates throughout the day.