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Generator Size Calculator

A crucial step in choosing a generator is ensuring that you get a model that will supply enough power for your home.  The chart below 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.

Most of the figures include 20% more 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.

 

Electrical Device Running Wattage Starting Wattage
1/2 HP Garage Door Opener 550 1375
Air Compressor (1 HP) 1440 3600
Airless Sprayer (1/3" HP) 600 1200
AM/FM Clock Radio 10 0
Belt Sander 950 2400
Box Fan (20") 113 0
CD/DVD Player 100 0
Cell Phone Battery Charger 25 0
Central A/C (10,000 BTU's) 1500 3000
Central A/C (24,000 BTU's) 3800 4950
Central A/C (40,000 BTU's) 3800 4950
Circular Saw - 7-1/4" 2100 5250
Clothes Dryer (Electric) 3600 9000
Clothes Dryer (Gas) 1800 4500
Coffee Maker 1300 0
Color TV - 13" 50 0
Copy Machine 1300 0
Crock Pot 240 0
Curling Iron 1500 0
Desktop Computer w/ 18" LCD Monitor 300 0
Dishwasher - Hot Dry 1200 3000
DVD Player 20 0
Electric Can Opener 70 0
Electric Drill - 1/2" 1100 1250
Electric Drill - 3/8", 4 Amps 480 1200
Electric Griddle 1500 0
Electric Stove - 8" Element 2100 0
Fax Machine 150 0
Food Processor 500 0
Furnace Fan Blower- 1/3 700 1400
Furnace Fan Blower (1/3 HP) 700 1400
Hair Dryer- 1250 Watt 1250 0
Hammer Drill 1600 1400
Heat Pump 4700 4500
Humidifier - 13 gal. 175 0
Inflator Pump 175 0
Inkjet Printer 10 0
Iron 1200 0
Laser Printer 400 0
LCD TV -32" 75 0
Light Bulb - 60 Watt 60 0
Light Bulb - 75 Watt 75 0
Microwave- 1000 Watts 1000 0
Microwave- 625 Watts 625 0
Miter Saw - 10" 1800 4500
Outdoor Light String 250 0
Planer/Jointer - 6" 1800 4500
Quartz Halogen Work Light (1,000w) 1000 0
Quartz Halogen Work Light (300w) 300 0
Quartz Halogen Work Light (500w) 500 0
Reciprocating Saw 1080 2700
Refrigerator/Freezer 550 1350
Security System 500 0
Space Heater 1500 0
Stereo Receiver 450 0
Sump Pump (1/2 HP) 1200 3000
Sump Pump (1/3 HP) 1140 2850
Table Saw/ Radial Arm Saw - 10" 1800 4500
Toaster 850 0
Toaster Oven 1500 0
Washing Machine 950 2400
Water Heater (Electric) 3800 0
Water Well Pump (1/4 HP) 575 1440
Window A/C (10,000 BTU's) 1000 2100
Window A/C (12,000 BTU's) 3250 3950
X-Box, Game Cube, Playstation 40 0