Generator Power Guide
How Much Power do you need?
This is the typical questions that everyone asks at one point or another. Most consumers do not understand how to calculate this into their consideration for what size generator will best suite their needs properly. Lets step back to high school physics.
- Watts = Volts x Amps
- Amps = Watts/Volts
You also need to take into consideration that some household items such as your refrigerator or freezer take more wattage to start them and less to keep it running. For example a typical refrigerator takes only about 700 watts to run it (yes, a full size refer/fridge combo). However, each time the compressor cycles it takes approximately 2200 watts to start it. This is the surge wattage of the appliance. We have listed below some typical items with there approximate required wattage. Keep in mind that if it is not listed you can also resort to calculating the requirement by using: Watts = Voltage x Amperage.
| Household Items |
Running
Wattage Requirements |
Additional Wattage Required For Starting |
| Coffee Maker |
1750 | 0 |
| Dishwasher - Cool Dry |
700 | 1400 |
| Electric Fry Pan |
1300 | 0 |
| Electric Range – 8-inch element |
2100 | 0 |
| Microwave Oven 625 watts |
625 | 800 |
| Refrigerator or Freezer |
700 | 2200 |
| Automatic Washer |
1150 | 2300 |
| Clothes Dryer – Electric |
5750 | 1800 |
| 1/8 Horsepower |
300 | 500 |
| 1/6 Horsepower |
500 | 750 |
| 1/4 Horsepower |
600 | 1000 |
| 1/3 Horsepower |
700 | 1400 |
| 1/2 Horsepower |
875 | 2350 |
| Lights | as indicated on bulb |
0 |
| Radio | 50 to 200 |
0 |
| Sump Pump |
||
| 1/3 Horsepower |
800 | 1300 |
| 1/2 Horsepower |
1050 | 2150 |
| Television - Color |
300 | 0 |
| Central Air Conditioner 10,000 BTU |
1500 | 2200 |
| Contractor | Running Wattage Requirements |
Additional Wattage Required For Starting |
| Air Compressor – 1 Horsepower |
1500 | 4500 |
| Bench Grinder – 8 inches |
1400 | 2500 |
| Hand Drill – 1/2 inch |
600 | 0 |
| High-pressure Washer – 1 Horsepower |
1200 | 3600 |
| Circular Saw, Heavy Duty – 7-1/4 inches |
1400 | 2300 |
| Electric Chain Saw – 14 inches, 2 Horsepower |
1100 | 0 |
| Table Saw -10 inches |
1800 | 4500 |
| Drills | ||
| 3/8 inch 4 amps |
440 | 600 |
| 1/2 inch 5.4 amps |
600 | 900 |
| Industrial Motors | Running
Wattage Requirements |
Additional Wattage Required For Starting |
| 1/4 Horsepower |
600 | 1000 |
| 1/2 Horsepower |
875 | 2300 |
| Capacitor Start Induction Run | ||
| 1/3 Horsepower |
720 | 1300 |
| 1 Horsepower | 1600 | 4500 |
| Capacitor Start Capacitor Run | ||
| 11/2 Horsepower |
2000 | 6100 |
| Fan Duty |
||
| 1/4 Horsepower |
650 | 1200 |
| Farm Equipment |
Running Wattage Requirements |
Additional Wattage Required For Starting |
| Electric Fence, 25 miles |
250 | 0 |
| Milk Cooler |
1100 | 1800 |
| Milker (vacuum pump) – 2 Horsepower |
1000 | 2300 |
| 50,000 BTU |
400 | 600 |
| 90,000 BTU |
500 | 725 |
| 150,000 BTU |
625 | 1000 |
| 15 amp | 380 | 0 |
| 60 amp with 250-amp boost |
1500/5750 | 0 |
| 100 amp with 300-amp boost |
2400/7800 | 0 |
| 200 amp AC |
9000 | 0 |
| 230 amp AC, at 100 amp |
7800 | 0 |
| Air Compressors |
Running
Wattage Requirements |
Additional Wattage Required For Starting |
| 1/2 Horsepower |
975 | 1600 |
| 1 Horsepower | 1600 | 4500 |
| Computers | Running
Wattage Requirements |
Additional Wattage Required For Starting |
| Desktop | 600 to 800 |
0 |
| Laptop | 200 to 250 |
0 |
| Monitor | 200 to 250 |
0 |
| Fax | 600 to 800 |
0 |
| Printer | 400 to 600 |
0 |