Generator Requirements
Understanding Running vs. Starting (Surge) Loads
Many devices have different power requirements when they start up compared to when they run continuously:
- Running Load: This is the continuous power a device needs to operate under normal conditions.
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Starting (Surge) Load: Devices with motors or compressors—such as refrigerators, air conditioners, and power tools—often require a temporary surge of power to start. This surge can be 2–3 times (or more) the running wattage. Look for “starting wattage” or “surge wattage” in the device’s manual or specifications.
Example: An A/C unit may demand a surge wattage of 2,400 watts to kickstart itself, but then only use 1,200 watts to run continuously.
It's important to account for surges because a generator can only put out so much electrical wattage at a given time. Overloading the generator could damage it and leave you without power.
Recommended Size
{{ findNextGeneratorSize(addSafetyFactor(startingLoad)) }} W ({{ formatKW(findNextGeneratorSize(addSafetyFactor(startingLoad))) }})
Starting Wattage
{{ roundUpToNearestHundred(addSafetyFactor(runningLoad)) }} W ({{ formatKW(addSafetyFactor(runningLoad)) }})
Running Wattage
Estimated Generator Load
{{ startingLoad }} W |
{{ runningLoad }} W
Recommendations
Add devices to generate recommendations.
Add at least 2 devices to generate the chart.
{{ highestDrawCalculations['Highest Starting Item'].name }}
{{ formatKW(highestDrawCalculations['Highest Starting Item'].loadStarting) }}
{{ highestDrawCalculations['Highest Running Item'].name }}
{{ formatKW(highestDrawCalculations['Highest Running Item'].loadRunning) }}
Add Device - Enter Horsepower OR Wattage.
Check the Nameplate or Manual:
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Most appliances have a label or a section in the manual that indicates their power consumption. This might be listed as:
- Wattage/Watts (W): Typical for most household devices
- Starting and Running Wattage (W): Found on larger devices like A/C units
- Horsepower (HP): Common for heavy machinery like pumps and compressors
- Volts and Amps (V and A): If you can't find Wattage, Volts and Amps can be converted to Watts using this formula:
Watts = Amps × Volts
Example: If a device uses 10A at 120V, its power consumption is approximately 1,200W.
The device in the picture draws 460 W. (115 V * 4 A)
- If the device lists a range of wattages, assume the highest amount.