Understanding generator power ratings is crucial when selecting a model that can safely and efficiently meet your home’s electrical demands. Generator power output is typically categorized by running watts (the amount of electricity a generator can provide continuously) and starting watts (the surge capacity needed to start large appliances).

Most homes have a mix of devices with different wattage needs. For example, a refrigerator may require 700 running watts but 1,400 starting watts. If you're running multiple appliances simultaneously—like an air conditioner (3,800W), water heater (4,000W), and lights (300W)—you’ll need a generator that can support both the base load and the initial startup surge. Ignoring starting watts can result in overloaded systems, flickering power, or damage to appliances.

Our generator wattage calculator helps homeowners understand the total wattage their appliances require and recommends generators accordingly. A small home (under 1,000 sq ft) might only need 3,000–5,000W. A mid-size home (1,000–2,500 sq ft) typically needs 7,500–12,000W, while a large home with HVAC, sump pumps, and electric dryers could require a 20,000–25,000W standby unit.

Using the correct wattage not only keeps your home running smoothly during outages but also helps avoid unnecessary spending on overpowered units. You’ll also improve fuel efficiency, reduce wear and tear, and extend the life of your generator. This page walks you through how to calculate power needs, provides examples of appliance loads, and offers insights into selecting a generator size that fits your lifestyle.