Home Appliance Wattage & Generator Sizing Guide

For critical basics (refrigerator, sump pump, lights, Wi-Fi, and TV), a 3,500W to 5,500W generator is typically sufficient. If you plan to run a central air conditioner (3-ton+) or an electric water heater, you will generally require a 10,000W to 12,000W generator or an electronic soft starter.

Running (rated) watts represent the continuous power required to keep an appliance running. Starting (surge) watts refer to the brief 2–3 second power spike needed by motorized compressors (like AC units and refrigerators) to start up from a standstill.

To prevent engine overheating, voltage fluctuations, and premature equipment wear, it is recommended to operate a generator at no more than 80% of its rated capacity for prolonged runtimes (e.g., pulling a continuous 4,000W on a 5,000W rated generator).

A 7,500W generator can comfortably run most essential 120V household loads simultaneously (refrigerator, freezer, lights, microwave, sump pump). However, it usually cannot run a central air conditioner and an electric water heater at the exact same time without careful load management.