1. What is a Whole House Generator Size Calculator?

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

Purpose: It helps homeowners and electricians determine the appropriate generator capacity needed to power an entire home during outages.

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 wattage 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 you want to power simultaneously, and the 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 provides capacity for future electrical needs.

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

Q3: When would I change the safety factor?
A: Use 1.5 for homes with many motor-driven appliances (AC, pumps), or 1.1-1.2 for mostly resistive loads (lights, electronics).

Q4: Should I size for everything or just essentials?
A: This depends on your needs - calculate both scenarios to compare generator sizes and costs.

Q5: Does this include starting watts?
A: The safety factor helps cover starting watts, but for precise sizing you should account for each appliance's starting watts specifically.