Whole House Generator Calculator

Generator Size Formula:

\[ Total\ Watts = \sum Running\ Watts + Max\ Starting\ Watts \]

Total Generator Size Needed (W):

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1. What is a Whole House Generator Calculator?

Definition: This calculator estimates the size of generator needed to power your entire home based on the total running watts and maximum starting watts of your appliances.

Purpose: It helps homeowners and contractors determine the appropriate generator capacity for residential backup power systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Total\ Watts = \sum Running\ Watts + Max\ Starting\ Watts \]

Where:

\( Total\ Watts \) — Required generator capacity (watts)
\( \sum Running\ Watts \) — Sum of all running watts for appliances
\( Max\ Starting\ Watts \) — Highest starting watts among appliances

Explanation: The total running watts plus the largest starting watts (from motors starting simultaneously) determines the peak load your generator must handle.

3. Importance of Proper Generator Sizing

Details: Correct sizing ensures your generator can handle startup surges while being efficient during normal operation. Undersizing can damage appliances, while oversizing wastes fuel and money.

4. Using the Calculator

Tips:

Add up the running watts of all appliances you want to power simultaneously
Identify the appliance with the highest starting watts (typically AC units, refrigerators, or well pumps)
Enter these values to get your total generator requirement

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between running and starting watts?
A: Running watts are what an appliance uses continuously. Starting watts (surge watts) are the extra power needed briefly when motors start (typically 2-3x running watts).

Q2: Should I size up from the calculated value?
A: It's recommended to add 10-20% buffer to the calculated total for safety and future expansion.

Q3: How do I find appliance wattage?
A: Check appliance labels, manuals, or use our Appliance Wattage Calculator. Typical values: fridge (700W running, 2200W starting), AC (1500W/4500W).

Q4: What if I won't run all appliances simultaneously?
A: Only include appliances you'll use together. You might calculate different scenarios (essential circuits vs. whole house).

Q5: Does this account for power factor?
A: This simple calculator doesn't. For precise sizing, consult an electrician who can consider power factor and other electrical characteristics.