I still have a little 3500w portable for....whatever. When we did the remodel on the kitchen and bath, we budged $5000 for a whole house unit based on what our contractor would do. That meant, I had to do some of the work. Farm & Fleet for the 18/20kw Generac generator, with the whole house Nexus controller and 200amp smart switch, a little over $4000+tax. We were also upgrading the service drop to 200amp, and an outside disconnect on the kitchen budget. All that work done at the same time. I went and got the generator on my trailer. Dug and poured a concrete pad for better stability than the plastic one commonly used. Had a neighbor with a skid steer set it on the pad. We have natural gas, but it will also run propane. Dug part of the area for pipes and wires. That was 10 years ago and that same generator is still under $5000. I shopped around and one store sold it to me for $500 less than another. I service it. But if need be, local companies can be hired to do annual service.
Power goes out, 20 seconds or so later it is running. Adjusting valves is easy. It looks similar to a Kawasaki V twin. Of course, we have to be smart enough to not run two driers and the A/C at the same time as everything else in the house is on. Might run it all. The only time you can tell when something turns on and puts a draw on the generator is the A/C. No sense in working it hard.
Whole house units can be affordable. Sure beats dragging the portable out of the shed. Running extension cords. Pulling a cold generator to start when it's -6F outside in a 30mph wind. During a 4 day outage, the house next door froze it's pipes and they burst. Flooding the basement 3 foot deep. Furnace ruined, and not able to pump it dry and keep it dry. It sat until mid spring. Then got abandoned and foreclosed on.
To keep it John Deere related, here is a pic. You can just see it behind a bush between the tractors. Exhaust facing away from the house. A neighbor actually softened their vinyl siding near theirs. You cannot see the sidewalk between the generator and the house, which is why it's so far away. We also did not want any fumes hanging under the overhang of the roof. Or coming in any of the windows which could be open.