A true whole-house generator produces enough electricity so you can operate appliances in your home normally. A large standby generator and installation costs thousands of dollars, depending on the size of your home and family.
Many families can get by with a smaller generator with enough power to run a refrigerator, some lighting and a sump pump. If you use electric heat and you’re concerned about freezing pipes during a winter outage, you’ll need a whole-house size. If you heat with gas, propane or oil, a smaller generator provides enough power.
The size of standby generator you select depends on how many electric items you want to operate during a power outage, and the sum of their wattages. Wattages are listed on appliance nameplates. Many appliances with motors, like refrigerators, require greater starting wattages for a short period than the continuous usage listed on the nameplate.
The “rated power” output of any generator is the wattage it can produce continuously; the “maximum rated power” is the wattage it can produce for a maximum of 30 minutes or so. Running at maximum output longer can damage the generator.
A 15-kilowatt (kW) generator will handle a typical family’s power needs. If you don’t run too many appliances simultaneously, a 10-kW size should be enough.
Natural gas, propane and diesel are the main fuels for standby generators. Most people select natural gas if available, which is clean burning, can be less expensive and doesn’t require a storage tank.
Propane also burns cleanly, but is more expensive and needs a storage tank. Diesel-powered generators are less common.
JAMES DULLEY is a nationally syndicated columnist who writes on energy efficiency and do-it-yourself energy topics.