1. What is a Generator Size Calculator?

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

Purpose: It helps homeowners, businesses, and contractors determine the appropriate generator capacity for backup power needs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Generator size (kilowatts)
• \( \sum P_{load} \) — Total electrical load (watts)
• \( SF \) — Safety factor (typically 1.2 for residential use)

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

3. Importance of Proper Generator Sizing

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

4. Using the Calculator

Tips:

• Sum the wattage of all devices you want to power simultaneously
• Use default safety factor of 1.2 for residential applications
• Increase safety factor to 1.5 for commercial/industrial use
• All values must be > 0

5. Frequently Asked Questions (FAQ)

Q1: Why do we need a safety factor?
A: The safety factor accounts for startup surges (especially for motors) and provides capacity for future additions.

Q2: What's a typical safety factor?
A: Residential: 1.2-1.3, Commercial: 1.3-1.5, Industrial: 1.5-2.0 depending on load types.

Q3: How do I find the total load?
A: Add the wattage of all devices you want to power simultaneously. Check appliance labels or use our Load Calculator tool.

Q4: Should I round up the generator size?
A: Yes, generators are typically sold in standard sizes - round up to the nearest available size.

Q5: Does this include HVAC systems?
A: Yes, but remember HVAC systems have high startup currents - include their rated wattage in your total.