1. What is a Generator Size Calculator?

Definition: This calculator estimates the required generator size in kilowatts based on the total electrical load and a safety factor.

Purpose: It helps homeowners, contractors, and facility managers determine the appropriate generator capacity for their power needs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Generator size (kilowatts)
• \( \Sigma P_{load} \) — Total electrical load (watts)
• \( SF \) — Safety factor (typically 1.2-1.5)

Explanation: The total load in watts is converted to kilowatts (divided by 1000) and multiplied by a safety factor to account for startup surges and future expansion.

3. Importance of Proper Generator Sizing

Details: Correct generator sizing ensures reliable power during outages, prevents overload conditions, and optimizes fuel efficiency.

4. Using the Calculator

Tips: Enter the total electrical load in watts and safety factor (default 1.2). The safety factor should be between 1.2 and 1.5 for most applications.

5. Frequently Asked Questions (FAQ)

Q1: How do I determine my total electrical load?
A: Sum the wattage of all devices that will run simultaneously, or use our Electrical Load Calculator tool.

Q2: What's a typical safety factor?
A: 1.2 is common for residential use, while 1.3-1.5 is used for commercial applications with motor loads.

Q3: Should I include startup currents?
A: Yes, the safety factor accounts for startup surges. For large motor loads, you may need a higher factor.

Q4: What if I have three-phase equipment?
A: This calculator is for single-phase loads. For three-phase, use our Three-Phase Generator Calculator.

Q5: How much extra capacity should I plan for?
A: Consider 20-30% extra capacity (safety factor) for future expansion and optimal generator performance.