Appliance Wattage & Running Cost
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What size generator or power station for an electric water heater? (5,000+ W)

To run an electric water heater, choose at least
5,000 W running.

An electric water heater draws about 4,000 W while running. Pick a generator, inverter or power station rated comfortably above these numbers.

Battery runtime calculator

Estimated runtime

Assumes about 85% usable capacity. Motors need extra headroom for startup surge.

How long a power station lasts

Power stationEstimated runtime
300 Wh0 h 4 min
500 Wh0 h 6 min
1,000 Wh0 h 13 min
2,000 Wh0 h 26 min
3,000 Wh0 h 38 min

Sizing guide

Minimum running watts5,000 W
Minimum starting watts5,000 W
Suggested inverter5,000 W or higher

See also electric water heater wattage and running cost.

FAQ

How many watts does an electric water heater use?

Tank models use about 3000-5500 watts while the element is heating.

How can I cut water heating costs?

Lower the thermostat to 120F, insulate the tank and fix hot-water leaks.