1. What is a House Generator Sizing Calculator?

Definition: This calculator estimates the appropriate generator size in kilowatts (kW) based on your total electrical load and a safety factor.

Purpose: It helps homeowners and electricians determine the right generator capacity for backup 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 1.25 for residential)

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

3. Importance of Proper Generator Sizing

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

4. Using the Calculator

Tips: Enter the total wattage of all appliances/equipment you want to power simultaneously and the safety factor (default 1.25). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I calculate my total load?
A: Add up the wattage of all devices you want to run simultaneously. Check appliance labels or use our Load Calculator tool.

Q2: Why is the safety factor important?
A: It accounts for motor startup surges (which can be 3-5x running watts) and potential future power needs.

Q3: When would I change the safety factor?
A: Use 1.5 for heavy motor loads (well pumps, AC units) or 1.1 for only lighting/electronics.

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 whole-house needs?
A: This calculates based on your input. For whole-house, include all essential circuits or use our Whole-House Calculator.