Electric water heater cost calculator
How Much Does an Electric Water Heater Cost to Run?
Estimate the electricity cost of an electric water heater from its element wattage, daily heating time, and your electricity price.
Cost estimate
Calculate your electricity cost
Estimated energy use0 kWh/day
Estimated monthly energy0 kWh/month
Cost = watts ÷ 1,000 × hours used × electricity price.
Example
How the starting estimate works
At 4,500 watts for 3 hours of active heating per day, the example uses 13.5 kWh per day before multiplying by your electricity price.
Real-world use
The heating elements do not run all day.
A tank water heater cycles its elements on and off as needed. Enter estimated active heating time rather than treating the element rating as a continuous 24-hour load.
Element wattage is not daily energy use
A 4,500-watt element does not normally run 24 hours a day.
Tank water heaters switch their heating elements on when stored water needs to be reheated. Daily electricity use depends on how much hot water the household draws, the incoming water temperature, thermostat setting, tank insulation, standby heat loss, and recovery after showers or other large draws.
Use the “hours used per day” field as an estimate of total active element time, not simply the number of hours the heater is powered on.
Hot-water demand drives cost
More gallons and a larger temperature rise require more energy.
Long showers, multiple occupants, high-flow fixtures, laundry, and dishwashing can increase the amount of water that must be reheated. Winter inlet water can also be colder, increasing the temperature rise required to reach the tank setpoint.
Tank vs heat-pump water heaters
This simple wattage calculator fits resistance heating best.
Heat-pump water heaters move heat from surrounding air and can use far less electricity than standard resistance elements under suitable conditions. Their power draw and operating pattern are different enough that a simple element-wattage estimate can be misleading.
For bill terminology and usage-based rates, see How to Read an Electric Bill.