1. What is a Whole House Generator Size Calculator?

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

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

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 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 your generator can handle all essential loads without being oversized, which improves efficiency and reduces costs.

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

Q2: Why is a safety factor needed?
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: Residential applications typically use 1.25, while commercial may use 1.5 or higher depending on requirements.

Q4: Should I round up the generator size?
A: Yes, generators come in standard sizes, so round up to the nearest available model.

Q5: Does this include HVAC systems?
A: Yes, if you included their wattage in your total load. Remember HVAC systems have high startup surges.