1. What is a Whole House Generator Sizing Calculator?

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

Purpose: It helps homeowners and electricians determine the correct generator capacity for backup power during outages.

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 1.25 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 sizing ensures your generator can handle all essential loads without being overloaded, while avoiding unnecessarily large and expensive units.

4. Using the Calculator

Tips: Enter the total wattage of all appliances/lights 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 find my total electrical load?
A: Add up the wattage of all appliances/lights you want to run simultaneously, or use our Electrical Load Calculator.

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

Q3: What's a typical safety factor?
A: 1.25 is common for residential, while commercial may use 1.5 or higher depending on critical needs.

Q4: Should I size for all circuits or just essentials?
A: This depends on your needs - most homeowners size for essential circuits (fridge, furnace, lights) plus a few comforts.

Q5: Does this include generator efficiency losses?
A: The safety factor typically covers efficiency - modern generators are about 90-95% efficient at converting fuel to electricity.