Select a whole-house generator based on the electrical devices you want to power during an outage, the noise the unit produces, and the cost. Decide if the ability to operate an air conditioner or heat pump during the outage are worth the additional cost.
Sizing is one of the factors to consider before making the purchase. Most generator manufacturers have online calculators that allow homeowners to enter the devices they want to power during an outage to determine the correct generator size. Also consider the power rating of the electric service of the home. As of 2015, most new homes in the United States have a 200-amp electrical system, but most homeowners are able to supply all of their electrical needs with a less powerful generator.
A whole-house generator provides power for essentials such as lights, refrigeration, sump pumps and electronics. Larger and more expensive whole-house generators provide enough power to operate air conditioning units and laundry appliances. In areas where heat and humidity are not usually a problem during an outage, it is possible to save costs by selecting a smaller unit. If laundry can wait when the power is out, you do not need to include an electric washer or dryer in the calculations.
Standby generators must go through a weekly system check to ensure that they can power the home in an emergency, and this process creates noise. If noise is an issue in your household, a quieter generator with noise-reducing features is your best choice.