A crucial step in choosing a generator is ensuring that you get a model that will supply enough power for your home. Our calculator, which provides an average wattage rating for most common electricity-using household appliances and devices, will help you tally your needs. Remember that when you've lost the power at your home, you probably will not run every appliance or device--generators are intended to temporarily provide for your basic needs during an emergency situation.

Note that the figure generated by the calculator includes 20 percent more watts than the actual total. This addition compensates for differing wattage ratings among appliances and device; it also accounts for the fact that the circuit breakers on a generator tend to shut off power before maximum load is reached, a move designed to protect the wiring.

Don't be surprised if the initial wattage total you get seems high. You might need to run the calculation two or even three times before you arrive at a figure that more accurately matches your essential requirements.