1. What is a Whole Home 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 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 1.25 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 conditions, and maximizes fuel efficiency.

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 power simultaneously. Check appliance labels or manuals for wattage information.

Q2: Why is a safety factor needed?
A: The safety factor accounts for motor startup surges (which can be 3-5x running watts) and potential future power needs.

Q3: What's a typical safety factor?
A: 1.25 is common for residential use. Commercial applications may use 1.5 or higher depending on criticality.

Q4: Should I size for everything at once?
A: No, only essential circuits/appliances. Consider load management for large loads like AC units.

Q5: Does this include generator efficiency?
A: Modern generators are typically 90-95% efficient, which is already factored into manufacturer kW ratings.