12 kw is enough. A 50 square meter facade is a 50 square meter storefront. Generally, a 50-square-meter store room can be renovated into a small hotel. Then you need 2 kW blower, 3 kW air conditioner, 2 kW lamps, 3 kW refrigerator and other small household appliances. I have a 2 kW backup power supply.

Kilowatt, which used to be power in the early days, now has a tendency to extend to unit of power in the whole field of physics. In electricity, kWh and kWh are exactly the same, but the names are different.