1. What is a Generator Size Calculator?

Definition: This calculator estimates the size of generator needed for a house based on the total electrical load and a safety factor.

Purpose: It helps homeowners and electricians 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 needed (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 you want to power simultaneously and a safety factor (default 1.25). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How do I find my total load?
A: Add up the wattage of all appliances you want to run simultaneously. Check appliance labels or manuals for wattage.

Q2: Why is a safety factor needed?
A: It accounts for startup surges (especially for motors) and provides capacity for future additions.

Q3: What's a typical safety factor?
A: 1.25 is common for residential, but 1.5 may be needed for heavy motor loads.

Q4: Should I round up the generator size?
A: Yes, always round up to the nearest standard generator size available.

Q5: Does this include whole-house needs?
A: Only if you include all house circuits. For partial loads, only include the circuits you want to power.