1. What is a Generator Size Calculator?

Definition: This calculator estimates the required generator size in kilowatts (kW) 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)
• \( P_{load} \) — Total electrical load (watts)
• \( SF \) — Safety factor (typically 1.2 for residential use)

Explanation: The total load in watts is converted to kilowatts (divided by 1000) and then 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 supply, 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). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why do we need a safety factor?
A: The safety factor accounts for motor startup currents (which can be 3-5x running current) and potential future load additions.

Q2: What's a typical safety factor?
A: For residential use, 1.2 is common. Commercial/industrial applications may use 1.5 or higher depending on the load types.

Q3: How do I find my total electrical load?
A: Sum the wattage of all devices that might run simultaneously, or use our Electrical Load Calculator tool.

Q4: Should I round up the generator size?
A: Yes, generators are typically sold in standard sizes (e.g., 5kW, 7.5kW, 10kW) - round up to the nearest available size.

Q5: Does this include surge capacity?
A: The safety factor helps account for surges, but for loads with high starting currents (like AC units), you may need additional margin.