1. What is a Generator Size Calculator?

Definition: This calculator estimates the required generator size (in kW) to power a home based on the total electrical load and a safety factor.

Purpose: It helps homeowners and electricians determine the appropriate generator capacity for backup power needs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Generator size (kilowatts)
• \( \sum P_{load} \) — Total electrical load (watts)
• \( SF \) — Safety factor (typically 1.25 for residential)

Explanation: The total load is converted from watts to kilowatts, then multiplied by a safety factor to account for startup surges and future needs.

3. Importance of Proper Generator Sizing

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

4. Using the Calculator

Tips: Enter the total wattage of all appliances you want to power simultaneously and a safety factor (default 1.25). 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 surges (which can be 3-5x running watts) and potential future power needs.

Q2: How do I find my total load?
A: Add up the wattage of all appliances you want to run simultaneously, or use our Load Calculator tool.

Q3: When would I change the safety factor?
A: Increase to 1.5 if you have many motor-driven appliances, decrease to 1.1 if only powering resistive loads (lights, heaters).

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

Q5: Does this include startup surges?
A: The safety factor helps cover surges, but for homes with many large motors, you may need to calculate surge watts separately.