The power output of the standard gasoline generator is described in terms of thousands of watts, or kilowatts. In the event that you need to determine if a gas generator meets your energy needs, you may have to convert the power requirement of the appliances to be run from amperes (amps) to watts.
The wattage of a gas generator is the amount of power it is capable of supplying. This power output can be expressed in terms of: Watts (W) = Amps (A) x Volts (V). With the standard voltage of a U.S. appliance being either 120 or 240 volts, start by totaling up the amperage requirement of the 120-volt appliances you want to power. For example, a 17.4-cubic-foot refrigerator/freezer might draw 9.7 amps and a 13-inch TV might draw 4.5, for a total of 14.2 amps.
Total up the amperage requirement of the 240-volt appliances. For example, if you have an electric range that requires about 9 amps and a clothes dryer that requires 28 -- your total amp requirement for 240-volt appliances is 37.
Multiply each amp total by the appropriate voltage to get total wattage. For 120-volt appliances, multiply the total by 120. For a 120-volt total of 14.2 amps, W = V x A = 120 x 14.2 = 1,704 watts. For 240-volt total of 37 amps, W = V x A = 240 x 37 = 8,880 watts.
Add the 120-volt wattage total and the 240-volt wattage total to get the total power demand of the gas generator. So, if the 120-volt total is 1,704 watts and the 240-volt total is 8,880 watts, then total demand is 10,584 watts. If you are using a 15-kilowatt generator, the power output of 15,000 watts should be a sufficient supply for this total.
Some appliances require a higher surge of power at start-up and then run at a much lower wattage. Be sure to note the start-up power demand in any calculations.
