1. What is a Whole Home Generator Calculator?

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

Purpose: It helps homeowners and electricians determine the appropriate generator size for whole-house power backup.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Generator power (kilowatts)
• \( \sum P_{load} \) — 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 overload damage, and improves fuel efficiency.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is the safety factor for?
A: It accounts for motor startup surges (which can be 3-5x running watts) and provides capacity for future additions.

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: Use 1.5 for heavy motor loads (well pumps, AC units), or 1.1-1.2 for mostly resistive loads (lights, electronics).

Q4: Should I include all home circuits?
A: Only include essential circuits you want to power during an outage. Consider load management for large homes.

Q5: Does this account for generator efficiency?
A: No, this calculates required output. Generator ratings already account for their efficiency.