Figure out exactly what you’re planning to use the portable generator for. You cannot use portable generator for very large appliances, such as whole-house air conditioners or swimming pool heat pumps. However, you can use it for most other appliances.
Calculate the amount of watts the generator will need to power at any given time. You need to determine the approximate electrical load for all appliances that may be powered at the same time by the generator. Each of your household appliances should be labeled with how many watts they require. These might be measured in watts or kilowatts. One kilowatt is equal to 1,000 watts.
Look for portable generators that support the amount of watts needed to power all the appliances you plan to power with the generator at one time. For example, your refrigerator and television might both require 2.4 kilowatts to operate. If these were your only two appliances, you could pick a generator to power just your refrigerator or both the refrigerator and the television.
Overestimate. Whatever you determine as your maximum watt needs for the generator, pick a portable generator with more power than that. If you’re powering mainly smaller appliances, such as a coffee machine on a camping trip, choose a portable generator that powers several more watts. If you’re powering larger appliances, such as your refrigerator or furnace, choose a portable generator with at least one extra kilowatt of power.
Pay attention to the physical size of the generator if you’re planning to take it with you on camping trips or picnics. It needs to be able to fit in the vehicle you plan to transport it in.