How much does it cost to run a tankless electric water heater?
A tankless electric water heater costs about $1.82 a day, $55.47 a month and $666 a year at typical use (3,700 kWh a year) and the U.S. average rate of 17.99¢/kWh. Whole-house electric tankless heaters draw 18-36 kW but only while hot water flows, and they avoid tank standby loss. They usually save about 10-20% versus an electric tank but need 100-150 A of dedicated circuits.
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Cost by setting
| Setting | Watts | Per day | Per month | Per year |
|---|---|---|---|---|
| 18 kW | 18,000 | $1.36 | $41.40 | $497 |
| 24 kW | 24,000 | $1.81 | $55.20 | $662 |
| 27 kW | 27,000 | $2.04 | $62.09 | $745 |
| 36 kW | 36,000 | $2.72 | $82.79 | $994 |
At 3,700 kWh a year and 17.99¢/kWh.
Cost to run a tankless electric water heater in every state
The same tankless electric water heater costs $456 a year in North Dakota and $1,610 in Hawaii, at each state's average residential rate (12 months ending July 2026).
| State | Rate | Per month | Per year |
|---|---|---|---|
| North Dakota | 12.32¢ | $37.99 | $456 |
| Idaho | 12.65¢ | $39.00 | $468 |
| Nebraska | 12.86¢ | $39.65 | $476 |
| Louisiana | 12.99¢ | $40.05 | $481 |
| Utah | 13.32¢ | $41.07 | $493 |
| Nevada | 13.36¢ | $41.19 | $494 |
| Arkansas | 13.43¢ | $41.41 | $497 |
| Tennessee | 13.56¢ | $41.81 | $502 |
| Oklahoma | 13.70¢ | $42.24 | $507 |
| Montana | 13.84¢ | $42.67 | $512 |
| Kentucky | 13.92¢ | $42.92 | $515 |
| Missouri | 13.95¢ | $43.01 | $516 |
| Wyoming | 14.01¢ | $43.20 | $518 |
| Washington | 14.12¢ | $43.54 | $522 |
| Iowa | 14.13¢ | $43.57 | $523 |
| South Dakota | 14.20¢ | $43.78 | $525 |
| Mississippi | 14.77¢ | $45.54 | $546 |
| North Carolina | 14.77¢ | $45.54 | $546 |
| Kansas | 15.09¢ | $46.53 | $558 |
| Georgia | 15.12¢ | $46.62 | $559 |
| New Mexico | 15.32¢ | $47.24 | $567 |
| Florida | 15.39¢ | $47.45 | $569 |
| Arizona | 15.40¢ | $47.48 | $570 |
| West Virginia | 15.48¢ | $47.73 | $573 |
| Oregon | 15.50¢ | $47.79 | $574 |
| South Carolina | 15.64¢ | $48.22 | $579 |
| Texas | 15.96¢ | $49.21 | $591 |
| Minnesota | 16.22¢ | $50.01 | $600 |
| Alabama | 16.44¢ | $50.69 | $608 |
| Virginia | 16.48¢ | $50.81 | $610 |
| Colorado | 16.58¢ | $51.12 | $613 |
| Indiana | 16.94¢ | $52.23 | $627 |
| Delaware | 17.79¢ | $54.85 | $658 |
| Ohio | 18.25¢ | $56.27 | $675 |
| Wisconsin | 18.74¢ | $57.78 | $693 |
| Illinois | 18.79¢ | $57.94 | $695 |
| Pennsylvania | 20.70¢ | $63.83 | $766 |
| Maryland | 21.03¢ | $64.84 | $778 |
| Michigan | 21.05¢ | $64.90 | $779 |
| New Jersey | 23.78¢ | $73.32 | $880 |
| Vermont | 23.80¢ | $73.38 | $881 |
| District of Columbia | 24.20¢ | $74.62 | $895 |
| New Hampshire | 26.67¢ | $82.23 | $987 |
| Alaska | 26.85¢ | $82.79 | $993 |
| Connecticut | 27.99¢ | $86.30 | $1,036 |
| New York | 28.39¢ | $87.54 | $1,050 |
| Rhode Island | 29.27¢ | $90.25 | $1,083 |
| Maine | 29.31¢ | $90.37 | $1,084 |
| Massachusetts | 30.43¢ | $93.83 | $1,126 |
| California | 32.99¢ | $102 | $1,221 |
| Hawaii | 43.51¢ | $134 | $1,610 |
How to cut the cost
- Set the outlet temperature to 115-120°F; mixing scalding water with cold wastes energy.
- Install 1.5 gpm showerheads; lower flow means fewer kW needed.
- Avoid running two showers and the dishwasher at once if your demand charge or panel is limited.
- Flush and descale the unit yearly in hard water areas.
Cheaper ways to get the job done
Uses about 60-70% less energy than any electric resistance heater, tank or tankless.
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Compare with similar appliances
| Appliance | Watts | Typical use | Per month | Per year |
|---|---|---|---|---|
| Tankless electric water heater | 24,000 | 3,700 kWh a year | $55.47 | $666 |
| Electric water heater | 4,500 | 4,500 kWh a year | $67.46 | $810 |
| Heat pump water heater | 450 | 1,300 kWh a year | $19.49 | $234 |
| Point-of-use water heater | 3,500 | 15 minutes a day | $4.79 | $57 |
| Mini tank water heater | 1,440 | 450 kWh a year | $6.75 | $81 |
| Hot water recirculation pump | 25 | 24 hours a day | $3.29 | $39 |
Head-to-head comparisons
Frequently asked questions
How much does it cost to run a tankless electric water heater per hour?
A tankless electric water heater is usually measured per year rather than per hour. It uses about 3,700 kWh a year, which works out to $1.82 a day.
How much does it cost to run a tankless electric water heater per month?
At typical use (3,700 kWh a year), a tankless electric water heater costs about $55.47 a month and $666 a year, at the U.S. average rate. Enter your ZIP in the calculator above for your utility's rate.
How many watts does a tankless electric water heater use?
Most tankless electric water heaters use 13,000 to 36,000 watts, depending on the setting (18 kw 18,000 W, 24 kw 24,000 W, 27 kw 27,000 W, 36 kw 36,000 W). Check the label on the back or bottom for your model's exact rating.
How many kWh does a tankless electric water heater use?
About 10.13 kWh a day and 3,700 kWh a year at typical use (3,700 kWh a year).
Does a tankless electric water heater use a lot of electricity?
Yes. At 3,700 kWh a year it's one of the bigger loads in a home, about 35% of the average U.S. home's 10,492 kWh a year.
Is it cheaper to run a tankless electric water heater or an electric water heater?
At typical use, a tankless electric water heater costs about $666 a year versus $810 for an electric water heater. So the tankless electric water heater is cheaper by about $144 a year. Use the comparison table above to compare them at your own settings.
How can I lower the cost of running a tankless electric water heater?
- Set the outlet temperature to 115-120°F; mixing scalding water with cold wastes energy.
- Install 1.5 gpm showerheads; lower flow means fewer kW needed.
- Avoid running two showers and the dishwasher at once if your demand charge or panel is limited.
Rates updated 2026-10-21: EIA data through July 2026. Typical wattage and usage reviewed against DOE, ENERGY STAR and manufacturer specs. Methodology.