How Much Electricity Does a Water Heater Use?

A water heater draws about 4500 watts, or 4.50 kWh per hour. Enter your hours and electricity rate below for the exact cost per day, month and year.

–kWh per day
–
kWh / month
–
Cost / day
–
Cost / month
–
Cost / year

Wattage is pre-filled with a typical value for a water heater; change any field for your own device, usage and rate. Cost uses your rate × kWh — a US-average placeholder rate of $0.17/kWh is shown; enter your own from your bill for an accurate figure.

A water heater in watts and kWh

A water heater draws about 4500 watts while running. Energy is billed in kilowatt-hours (kWh), and one kWh is 1000 watts for one hour — so a water heater uses 4500 ÷ 1000 = 4.50 kWh for every hour it is on. Multiply that by the hours you use it and by your rate per kWh to get the cost. The calculator above does it live; change the wattage if your model differs. Kept up every day of the year at 3 hours a day, that is about 4,928 kWh — roughly $837.68 at the $0.17/kWh placeholder rate used here.

Water heating is one of the largest home loads; the element cycles to hold temperature.

Wattage moves with size, age and model, so treat 4500 W as a starting point rather than a fixed number. It is the standard element rating on 40- and 50-gallon tanks at 240 V; Rheem's 50-gallon Performance and Professional Classic models, for example, are rated 4500 W. The rating plate on your own appliance, or its ENERGY STAR listing, gives the figure to type in. The rate matters just as much: the US Energy Information Administration publishes current average residential prices by state, and the figure on your own bill is better still. This LK Forge calculator recomputes every result as you type.

How to cut what it costs

Two levers change the bill: hours of use and your rate per kWh. Running high-wattage devices less, or shifting them to off-peak hours on a time-of-use plan, has the biggest effect. For a whole-home estimate or to compare devices, use the full electricity bill & appliance calculator.

Other appliances

TV Space Heater Fridge Ceiling Fan Computer Dishwasher Dryer Washing Machine Oven Gaming PC Air Conditioner Microwave Hair Dryer Freezer Electricity calculator

Frequently Asked Questions

How much electricity does a water heater use?
A water heater uses about 4500 watts, or 4.50 kWh for every hour it runs. At 3 hours a day that is about 13.50 kWh per day; multiply by your rate per kWh for the cost. Three hours of element time a day over a 30-day month is about 405 kWh. Those hours are reheat time rather than 24-hour standby, so a well-insulated tank and lower hot-water demand cut the figure by making the element run less often.
How much does it cost to run a water heater?
The cost of running a water heater is the kWh it uses × your rate per kWh. At a US-average $0.17/kWh and 3 hours a day, a water heater costs about $2.30 a day and $68.85 a month. Enter your own rate above for an exact figure.
How is this calculated?
Electricity use for a water heater is calculated from watts: energy in kWh equals watts divided by 1000, multiplied by the hours of use. Cost is that kWh figure multiplied by your electricity rate. Your rate per kWh is on your utility bill.
How much does a water heater cost to run per year?
Running a water heater for 3 hours a day, every day, uses about 4,928 kWh a year. At the US-average placeholder rate of $0.17/kWh that is roughly $837.68 a year. Change the hours or the rate above and the yearly figure updates with them.