What does an electric water heater cost to run?

Run the numbers on your own use

Change any of these and the figures update. The defaults are the typical case described above; your rate is the input that moves the answer most.

Why this is lower than the number you will see elsewhere

Almost every published answer to this question multiplies the rating on the label by the hours the appliance is switched on. For an electric water heater that gives 39,420 kWh a year, or $7,230.

Elements fire only to replace heat drawn off or lost through the tank wall — about 1.6 hours of element time a day for a household of three to four, spread over many short bursts.

The arithmetic, step by step

Nothing here is hidden, so you can check it or change it. Working in the order the formula runs:

1. 4,500 W — what it draws while it is actually drawing. This is the rating on the plate.
2. × 7% — the share of its in-service time it is really pulling that. Elements fire only to replace heat drawn off or lost through the tank wall — about 1.6 hours of element time a day for a household of three to four, spread over many short bursts.
   That gives 311 W averaged across the hours it is on.
3. × 24 hours a day × 365 days — A 50-gallon tank serving a household of three to four.
   311 × 24 × 365 ÷ 1,000 = 2,720 kWh a year.
4. × 18.34¢ — the US average residential rate for June 2026.
   2,720 kWh × 18.34¢ = $499 a year.

Change any assumption in the calculator above and every figure on this page moves with it. The two that matter most are your rate, which varies 4× across the country, and the hours — the duty cycle is a property of the appliance, but the hours are a property of you.

How sensitive is that number?

A single figure invites more confidence than it deserves. Here is the same appliance under assumptions either side of the default, so you can see how much of the answer is the appliance and how much is the guess about how you use it.

Everything else held at the default. The spread here is the honest error bar on the headline figure.

What it costs per hour, day and month

At 18.34¢ per kWh, the US residential average for June 2026.

The thing worth knowing

This is the quiet second-largest line on most all-electric bills, and almost nobody guesses it. It is also the easiest to reduce, because a tank loses heat to the room every hour of the year whether anyone uses hot water or not.

Against heat pump water heater

A heat pump water heater cuts it by roughly two thirds. Short of replacing it: an insulating jacket on an older tank, and dropping the thermostat from 140F to 120F. In numbers: an electric water heater costs $499 a year on these assumptions, and heat pump water heater doing a comparable job costs $177 — a difference of $322 a year, or $3,221 over ten years at today’s rate.

Both at 18.34¢/kWh, each on its own standard usage assumption. Ten years is roughly the service life of either.

What it costs in your state

The appliance is the same everywhere; the rate is not. Running this electric water heater costs $1,434 a year in Hawaii and $357 in Nevada — a difference of 4×.

Cost of running one electric water heater for a year, by state. Residential average price, EIA June 2026.

Other water heating and pumps costs

• Hot tub

  $602 a year

  A 400-gallon tub held at 102F year round, well covered.

• Pool heat pump

  $576 a year

  Holding a residential pool at swimming temperature through an extended season.

• Pool pump

  $396 a year

  A single-speed pump on an eight-hour timer through the season.

• Koi pond pump

  $241 a year

  A pump circulating a mid-size koi pond through its filter, year round.

• Heat pump water heater

  $177 a year

  A 50-gallon hybrid in a basement, resistance backup rarely engaged.

• Septic aerator pump

  $112 a year

  An aerobic septic system running as intended.

Questions

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from