I'll try too answer this..
I purchased, a B & S "storm responder" from Sears.. 5K~6K watts.. Runs 11 hours on 5 gallons of gas.. (depending on the Load Cycle).. It is enough, I "TESTED" Loading on my home.. I was enough to power My computer/freezer/fridge/TV/ AND My AC/Heat pump.. (Barely all @ once)..
I also had a Generac 6000 that could do same amount of "load" , but less hours run time..
Hooking one up...
YOU CAN USE THE 120/240 "LINE OUTLET" TO Reverse plug per'se, into your DRYER outlet... making it a "inlet" into your home powering it.
DOING SO MAKE SURE YOU TRIP YOUR MAIN BREAKER TO THE GRID!!!!!!! aS "YOUR POWER" will go to the nearest transformer turning your measly power into 7K +/- volts possibly causing death too line workers thinking those power lines were not "energized"...
My house is "wired" for a Gen-set already.. All I have to do is trip My breaker & I'm set.. Generator runs in the detached garage..
Of course FOLLOW SAFTEY GUIDELINES, in other words Carbon monoxide poisoning..
Smaller portable generators (1000K ~ 3000K watts) are enough to power your fridge/freezer and maybe light & TV/Radio.. Though the extension cord outlets, (don't forget to buy those, AND long enough to have the generator OUTSIDE.. )
Edit too add, (about the transfer Switch on breaker panel),, I just cut the Main breaker..
I carry about 20 gallons of fuel, because I'm right on the main grid..
Generators are great to have in winter, In case of Ice Storms also..
Be sure (If you buy one) buy your gas cans NOW, you'll have mucho trouble finding some..
Plus I got a Boat tank that hold 30 gallons if I've got to use that too..