In the event of an extended power outage, a portable generator will provide the electricity needed to light and warm your home, and to use essential appliances and devices. Thinking of acquiring one? Read on for a concise buyer’s guide.

The first thing you need to know is that the majority of standby generators for home use are portable and powered by gasoline. They range in power from 1,000 to 6,500 watts. It’s essential to determine what electrical capacity you’ll need for your home, by calculating the total wattage of the appliances in use—and then adding a safety margin of 25% to cover the extra power it takes to start up appliances like a refrigerator or sump pump. Refer to the following table.



Approximate wattage required

Oil-fired central heating

1,200–1,800 (furnace and fan)

Gas-fired central heating

1,200–1,300 (fan)

Electric heating

1,500 (per 1.5 m [5 ft] baseboard heater)

Other appliances

Approximate wattage required

Water heater


Sump pump





1,500 (per element)

Electric light bulb

60–150 (per bulb)


Other criteria to consider before you buy

  • Noise: the noise level produced by newer generators is 65 decibels or lower, which is around the level of human speech.
  •  Run time: generators operate for between 5 to 11 hours on one tank of gas and oil.
  • Automatic voltage regulator: prevents damage to refrigerators, freezers, TVs, etc.
  • 12-volt charger: some models can be used to charge an automobile or marine battery.
  • Automatic idle control: reduces noise and prolongs the lifespan of the generator.
  •  Electric start: this feature allows the generator to be started at the touch of a button; all models, however, are equipped with a pull start (manual) system.
  • Automatic transfer switch: connected to the breaker panel, this switch manages the changeover to generator power when utility power is interrupted.

Safety first

During the ice storm crisis of 1998, approximately 100 people lost their lives and another 2,100 were injured because of misuse of generators. Manufacturers recommend the following:

  • Connection of a generator to an existing electric circuit must be done by a certified electrician because of the danger of electrocution.
  • An improperly installed generator may cause a short circuit or a fire.
  • Most generators are not designed for indoor use. Those that are must be connected to an appropriate exhaust system (vent, chimney or other).
  •  Outside, a generator must be located well away from doors and windows, as well as protected from inclement weather to prevent the carburetor or crankcase vent from icing up.
  • Before refilling the generator with gas, shut it off and allow it to cool completely.
  • Take care not to overload a generator: connect appliances one by one, respect the rated capacity, and use extension cords if needed.

A final note: in the event of a prolonged power outage in cold weather, having a gas- or wood-fired heating appliance in addition to a generator is a major advantage.