Running watts is the continuous power a Generac generator can deliver indefinitely, and surge watts is the higher burst of power delivered for two to three seconds to start motor loads. The distinction matters because electric motors draw two to three times their running wattage the moment they start, a spike that lasts only seconds but must fall within the generator surge capacity or the unit will trip its breaker.
As an example, a 22kW Generac Guardian is rated at 22,000 running watts and approximately 22,000 surge watts at 240V. A central air conditioner with a 3-ton compressor may draw 5,000 running watts but require a 15,000-watt starting surge. If a well pump, sump pump, and AC compressor all start within the same second, the combined surge demand can briefly exceed twice the combined running load. Properly sizing a generator means accounting for the largest simultaneous surge scenario in the home, not just the average running load.
Generac True Power Technology maintains output voltage and frequency stability during motor starting events, reducing the visible light flicker and equipment stress that occurs when cheaper generators sag under surge demand. Our licensed master electrician team can help you calculate your home surge scenario. Browse our Generac home standby generator collection or contact us for sizing guidance. Free Freight Insurance Included on every order.