Calculator › Wattage chart › Water heater (electric tank)
What size generator to run a Water heater (electric tank)?
Typical draw: 4500W running. 240V resistive load. On generator power, heat water in off-peak moments with other loads off — or skip it.
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Total running watts
4,500 W
Peak (largest start)
4,500 W
Buy at least
5,650 W rated
Look for ~5,650W running / 4,500W surge or better.
Right size: Mid-size portable (6,500W / 8,100W surge)
Storm essentials with margin: fridge, freezer, sump pump, furnace fan, well pump (240V models), lights and electronics together. Louder open-frame design; electronics prefer models with THD under 5% or an inverter.
See current prices on AmazonOne size up: Large portable (9,500W / 12,500W surge)
Most of a house through an interlock kit: well pump, multiple large appliances, even a smaller central AC with a soft-starter. Heavy (200+ lbs), thirsty, and loud — this is serious-outage equipment, not camping gear.
See current prices on AmazonAdd more appliances
Real outages aren't one appliance. Adjust the full load below — your Water heater (electric tank) is pre-checked.
This site earns commissions from qualifying purchases made through links to Amazon and other retailers, at no extra cost to you. Wattage figures are typical estimates — actual draw varies by model. Always verify against your appliance's nameplate, and consult a licensed electrician for any panel or hardwired connections.