[rfuerst911sc]

If cost is no issue I would prefer a water cooled unit vs air cooled. Water cooled are quieter and can run for much longer without issues. I would not rule out a clean used unit .

Size: obviously you need to add up all the load to figure out the size . Having said that are you REALLY going to run everything at the same time ? Example: you are surviving through a nasty storm . Power has been out for 24 hours .

Are you going to run the AC/heat , water heater , well pump , microwave , coffee maker , oven , washer/dryer at the same time ? I highly doubt it . My point is I believe the " average " home can get by with a 12k generator and a little bit of load management.

A smaller generator uses less fuel . Is that important ? Well look up fuel consumption for a 20k LP generator. If you have a 500 gallon tank which only holds 400 gallons and you are out of power for a week you are out of propane .

A clean and safe transfer switch install is a must, the last thing you want is to endanger the life of a utility line worker . Manually controlling load via breakers is simple enough but may not be for everybody .