Sizing A Generator For Home Use?

If I want a standby generator for power outages, do I just add up the wattage of the appliances I expect to run?
I'm guessing not - that at the very least, I'd want to add a fudge factor like ten for fifteen percent. -- PeteCresswell

"(PeteCresswell)" wrote in message

If I want a standby generator for power outages, do I just add up the wattage of the appliances I expect to run?
I'm guessing not - that at the very least, I'd want to add a fudge factor like ten for fifteen percent.

How long do you expect your longest power failures to be? Here in Florida where they can run into weeks (following a hurricane) it is very important to install the RIGHT size generator or you will end up with a massive fuel bill. The principle is this; a 4000-watt generator will produce 2000 watts while burning far less fuel than a 12,000 watt generator producing that same 2000 watts.
I find that a typical load for my house is about 2000 watts or less. Yes, there are times when it is higher and there are some things (like my central air) that I can't run at all with my 4000 watt Onan, and there are times that I have to manage my load. That said, even my little Onan could run up an astounding fuel bill if I ran it for 24/7/30. Just one gallon an hour (at current prices $2.55) would cost you $1,836 a month! I find that one of the most useful specifications for a standby generator is the fuel consumption at 50% load. Pay great attention.
Vaughn

"(PeteCresswell)" wrote in message

If I want a standby generator for power outages, do I just add up the wattage of the appliances I expect to run?
I'm guessing not - that at the very least, I'd want to add a fudge factor like ten for fifteen percent. -- PeteCresswell

That's how I would do it. The newer inverter-type generators are more efficient and quiet, due to the way they throttle-back automatically under lighter loads.
Another method is to build a battery bank and backup power supply. It's essentially like a big UPS (unterruptible power supply.) This consists of batteries, an inverter and an automatic transfer switch. This option is more costly than a standby generator, but operates seamlessly and silently with your conventional power. This option is better if you are running lighter loads and don't want a power failure to affect things like computers and clocks.