My A/C is 10kw running, with 18kw tankless water heater. You oversize generators when drawing lots of current from switch mode power supplies as harmonics confuse the AVR. Aka tankless water heater.
I have a home lab, full rack. Around 4kw including a dedicated A/C.
I have excess power and will run an extension cord to neighbors if needed.
I’d also want capacity to charge an EV should I get one.
Price between 22kw and 40kw was negligible relative to total project cost. The only downside is I have to turn on everything in the house twice a year to exercise it and avoid wet stacking.
Final note is that in order to use an automatic transfer switch you must have sufficient capacity for connected loads. A smaller generator would have forced me to install a second sub panel for loads I want to run during an emergency.
5kw is the normal running consumption. Startup currents are higher than normal operation and so you need to have a beefier generator. But yes, 40kVA is a lot, big houses should do fine even with high transient loads with a 22kVA generator.
But let’s not forget this is HN, maybe OPs house is humongous
Yes but you can't really buy generators with more than 22kw and even that is plenty to run the AC for a 5500 sq ft home with plenty of breathing room to run the electric washer/dryer
Oh of course you can buy generators that will run the utility circuit of a nuclear power plant, they need to come from somewhere. Somebody will sell you one. I have not personally seen a residential generator larger than 22.5kw when searching for homes in hurricane country. This is in response to a guy saying he has a giant 30+kw generator for his home, which would be... extremely unusual unless he was also running an off grid welding shop or something equally unlikely