Understanding Generator Sizing for Your Home
Choosing the right standby generator size is one of the most important decisions in a backup power project. An undersized unit will fail to deliver the power you need during an outage, while an oversized unit wastes money on capacity you will never use.
Key Factors in Generator Sizing
Several factors determine the generator capacity your home requires. These include your total electrical panel amperage (typically 100A, 150A, or 200A service), the specific circuits and appliances you want to power, the size and type of your HVAC system, and whether you have any large-draw items like electric ranges, well pumps, or hot tubs.
General Sizing Guidelines
For a general reference point, homes up to 1,500 square feet with gas heat typically need 10kW to 14kW. Mid-size homes between 1,500 and 3,000 square feet usually require 16kW to 22kW. Larger homes above 3,000 square feet, or homes with multiple HVAC zones and high-demand appliances, often need 22kW to 26kW or higher.
The Importance of a Load Calculation
The most accurate way to determine generator size is through a professional load calculation. A licensed electrician evaluates every circuit in your electrical panel, identifies which loads you want covered, accounts for starting surge requirements (especially for air conditioners and well pumps), and calculates the total running and peak wattage needed. This process ensures you select a generator that handles your real-world demand without being under or over capacity.
Common Mistakes to Avoid
Do not simply match the generator to your panel amperage. A 200A panel does not always need the largest generator available. Also, remember that air conditioners and heat pumps require significant starting surge capacity, sometimes 3 to 4 times their running wattage. If you plan to run central air during an outage, factor that surge into your sizing.
Our team at IB Lighting can help you evaluate your needs and select the right generator. Contact us at (800) 674-9019 for personalized sizing assistance.