Permanently mounted stand-by generators provide automatic power when the regular power supply is interrupted. Powered by gasoline or diesel fuel, they can power selected circuits within a few minutes of a power failure.
Depending on their wattage output, generators will run anything from a small lamp to a number of large appliances. To determine the size generator you will need to total the wattage of the maximum number of items you will be running simultaneously. For items with start up ratings higher than their run ratings, use the higher rating to determine your power requirements.
Inductive load appliances and tools such as refrigerators, washers, and power tools require additional wattage for starting the equipment. The initial load only lasts for a few seconds on startup but is very important when calculating your total wattage.
For example: running a 100 watt light bulb, a 200 watt slow cooker, a 1,200 watt refrigerator with a startup wattage of 2,900 watts and a 750 watt TV would require 3,950 watts.
Use the chart below to find the right generator for you. Be sure to read detailed Safety Tips following the chart.
|Appliance or Tool||Running Wattage*||Startup Wattage*|
|Light bulb (see marking on bulb)||50||0|
|Freezer (frost free) 24 cu. ft.||720||1890|
|Portable oil filled heater||1500||1800|
|Air Source Heat Pump (3 ton)||5400||7200|
|Ground Source Heat Pump (3 ton)||3000||5000|
|Central Air Conditioner (3 ton)||5400||7200|
|Room Air Conditioner 12,000 Btu||1412||0|
|Well Pump (1⁄2 hp)||150||1950|
|Computer – PC||300||0|
|Sump Pump (1/3 hp)||800||1250|
|Garage door opener (1⁄4 hp)||550||1000|
|Heater, Kerosene (90,000 Btu)||500||725|
*Wattage listed per item is an estimate; check your appliances for exact usage, or contact an electrician or a heating and air-conditioning professional for exact specifications of each item.
Generator Safety Tips:
Avoid dangerous electrical backfeeding!
Never exceed the rated capacity of a generator.
Follow these tips to protect against shock and electrocution:
The contents of this page (including the Chart) are available for download below.