LOL guys! My house uses a lot more than 15 kw. I have Central Air Conditioning in the Summer and Electric heat pump for winter. uses almost 30 amp 230 volt. Then add the 15 amps for the blower motor. We have 50 amp 230 volt for the stove/ oven. We have Electric dryer at 30 amp 230 volt. On demand hot water heater that uses up to 2 x 40 amp 230 volt circuits. To that add lighting, 3 computers, tv's, 1 large fridge, 1 large freezer, air compressor for the septic system, microwave oven etc. That adds up to a serious load.
i like COMFORT! We could alternate a lot of the loads but why do it if you have the generator that can do most of the loads to live in comfort - while others are just barely running the window A/C and their freezers and fridge.
I have been through a long power outage and it gets boring if you don't have power for the TOYS like TV and computers. You get the picture...
So please don't judge if some of us like the bigger output generator sets.
BTW I took a 15KW 400 HZ generator and turned it into a 42kw generator by replacing the generator head with a new civilian one. I took a bit of wiring because there were components missing from the 400 generator wireing. The head swap was the easy part!