1. Generator Sizing Basics

Proper generator sizing is crucial for powering your home during outages. The generator must handle the total wattage of all appliances you want to run simultaneously, plus a safety margin for startup surges.

2. How the Calculation Works

The calculator uses the formula:

Where:

• \( P_{total} \) — Required generator size (watts)
• \( \Sigma P_{loads} \) — Sum of all appliance wattages
• 1.2 to 1.5 — Safety factor accounting for startup surges

Explanation: The safety factor ensures the generator can handle momentary power surges when appliances start up (particularly motors in refrigerators, AC units, etc.).

3. Importance of Proper Sizing

Details: An undersized generator may fail to start appliances or trip its circuit breaker. An oversized generator is less efficient and more expensive to operate.

4. Using the Calculator

Tips:

• List all appliances you want to power simultaneously
• Use nameplate wattage or check appliance manuals
• For motorized appliances, use starting wattage if available
• Choose safety factor based on your needs (1.35 recommended)

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between running and starting watts?
A: Running watts are continuous power needs. Starting watts are higher momentary needs when motors start (typically 2-3x running watts).

Q2: How do I find my appliance wattage?
A: Check the nameplate, manual, or use a wattage meter. Common appliances: fridge (600-800W), AC (1000-4000W), microwave (600-1200W).

Q3: Should I size for all appliances or just essentials?
A: Size for what you need during outages. Many people prioritize fridge, lights, furnace, and a few outlets.

Q4: What about central air conditioning?
A: Central AC requires significant power (3000-5000W). You may need a large generator or consider window units during outages.

Q5: Can I connect a generator directly to my home wiring?
A: Only with a proper transfer switch installed by an electrician to prevent backfeeding, which is dangerous to utility workers.