What size Generator Should I Buy to Power House?
Here in Charleston SC we are used to hurricanes and as such generators are a must if don't want to be bothered with the inconvenience of power loss. Unfortunately, most people don't understand what size they should get if they want to buy one as protection against power loss.
Often times the public thinks you can buy a large inverter generator or large portable and that will power your home. Sadly that is not the case. It can power a lot of things, but an entire home it will not. That's where a whole home generator comes in. In the southeastern United States: Florida, Georgia, South Carolina, Alabama, Mississippi, Louisiana, North Carolina and the east coast of Texas there is an insane amount of humidity. Coupled with heat of the summer, a portable generator just doesn't have the power to keep the HVAC running should you lose power.
A large portable may be able to run just the HVAC of your home, and only one unit, but the problem is home over 3000 sq ft, have two units usually. One for upstairs and one for down. Then you wouldn't be able to also keep your refrigerator, TV, or lights on as well. We suggest at least a 22kW generator for the average home in America, and 24 if you have a larger than average.
The next issue with a portable vs an entire home standby generators is the conversion from grid to generator, I.E. taking your home off the grid to run power from the generator. Generac makes an automatic transfer switch so that when it detects power loss it will automatically switch your home to the generator. Otherwise, how do you get power to the things you want if they are plugged into the wall?
Yes, you can save thousands of dollars if you don’t mind having to pull your large inverter/portable generator out of a garage or shed and hook it up during the outage. It has to be at least 7500 watts and you'll still want to have a transfer switch installed by an electrician. This is assuming you have a house under 1800 sq ft. with only one refrigerator, etc. and standard appliances. That will still only run a small window AC unit.
Consumer Reports has done a neat little interactive tool on their page about sizing the right generator.
The bottom line is a portable is just not the right generator if you want safety and convenience for power loss. By the time you get a portable, deal with the hassle, you'll figure out it was the wrong idea. Just figure out how to get a home standby or you're going to regret it.