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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.

New Column New Column New Column
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