Adding up the running watts and the highest starting wattage of all the devices you wish to power with a generator will help ...

To determine whole-house generator sizing, the first step is for the homeowner to determine the number of appliances and electrical devices that will be run and calculate the total wattage.

Total Wattage: 1,050 + 350 = 1400 watts The total wattage you need to run a small refrigerator would be 1400 watts, so you would need a generator that provided at least that many watts.

Your generator also must have at least a 30-amp/240-volt output. To calculate wattage for a standby generator, check a year's worth of electric bills to find the highest kilowatt usage.