Tankless Water Heater running cost, by state
A tankless water heater drawing 18000W costs about $482 a year at the US average electricity rate — but that average hides a fourfold spread. Pick your state for a real figure.
At the US average rate
18000W at a 80% duty cycle, 0.5 hours a day, at 18.34¢/kWh.
About this appliance
Enormous instantaneous draw but zero standby loss. Whether it saves money depends heavily on household usage patterns and incoming water temperature - cold-climate installations need far more power for the same output temperature.
- At typical use this is a major load - around 2,628 kWh a year. Efficiency upgrades here pay back faster than on any small appliance.
- Models vary widely, from about 10000W to 28000W. Check the nameplate on your own unit rather than assuming an average, because the spread is more than 2x.
- If your utility offers time-of-use pricing, shifting this load off-peak can cut its cost substantially without using any less energy.
Annual cost in every state
Sorted cheapest first. Click any state for the full calculation with that state’s rate loaded.
| State | Rate /kWh | Per month | Per year | Relative |
|---|---|---|---|---|
| Nevada | 13.11¢ | $28.73 | $345 | |
| Nebraska | 13.25¢ | $29.04 | $348 | |
| Utah | 13.37¢ | $29.30 | $351 | |
| Louisiana | 13.49¢ | $29.57 | $355 | |
| Tennessee | 14.07¢ | $30.84 | $370 | |
| Arkansas | 14.12¢ | $30.95 | $371 | |
| North Dakota | 14.12¢ | $30.95 | $371 | |
| Kentucky | 14.26¢ | $31.25 | $375 | |
| Oklahoma | 14.33¢ | $31.41 | $377 | |
| Idaho | 14.37¢ | $31.49 | $378 | |
| North Carolina | 14.74¢ | $32.31 | $387 | |
| Mississippi | 14.88¢ | $32.61 | $391 | |
| Washington | 14.91¢ | $32.68 | $392 | |
| New Mexico | 15.06¢ | $33.01 | $396 | |
| Florida | 15.10¢ | $33.09 | $397 | |
| Montana | 15.14¢ | $33.18 | $398 | |
| Arizona | 15.18¢ | $33.27 | $399 | |
| Wyoming | 15.24¢ | $33.40 | $401 | |
| South Dakota | 15.36¢ | $33.66 | $404 | |
| West Virginia | 15.45¢ | $33.86 | $406 | |
| South Carolina | 15.55¢ | $34.08 | $409 | |
| Kansas | 15.71¢ | $34.43 | $413 | |
| Iowa | 15.93¢ | $34.91 | $419 | |
| Texas | 15.94¢ | $34.94 | $419 | |
| Missouri | 16.22¢ | $35.55 | $426 | |
| Oregon | 16.32¢ | $35.77 | $429 | |
| Georgia | 16.36¢ | $35.86 | $430 | |
| Alabama | 16.40¢ | $35.94 | $431 | |
| Colorado | 17.13¢ | $37.54 | $450 | |
| Virginia | 17.22¢ | $37.74 | $453 | |
| Indiana | 17.51¢ | $38.38 | $460 | |
| Minnesota | 17.52¢ | $38.40 | $460 | |
| Ohio | 19.19¢ | $42.06 | $504 | |
| Delaware | 19.29¢ | $42.28 | $507 | |
| Wisconsin | 19.56¢ | $42.87 | $514 | |
| Illinois | 19.89¢ | $43.59 | $523 | |
| Pennsylvania | 21.73¢ | $47.63 | $571 | |
| Maryland | 21.84¢ | $47.87 | $574 | |
| Michigan | 22.99¢ | $50.39 | $604 | |
| Connecticut | 24.32¢ | $53.30 | $639 | |
| District of Columbia | 24.39¢ | $53.46 | $641 | |
| Vermont | 24.44¢ | $53.56 | $642 | |
| New Jersey | 24.95¢ | $54.68 | $656 | |
| New Hampshire | 27.01¢ | $59.20 | $710 | |
| Alaska | 28.21¢ | $61.83 | $741 | |
| Rhode Island | 29.23¢ | $64.06 | $768 | |
| New York | 29.49¢ | $64.63 | $775 | |
| Maine | 29.59¢ | $64.85 | $778 | |
| Massachusetts | 29.61¢ | $64.90 | $778 | |
| California | 34.74¢ | $76.14 | $913 | |
| Hawaii | 52.72¢ | $116 | $1,385 |
Common questions
How many watts does a tankless water heater use?
A typical tankless water heater draws about 18000 watts while running, with most models falling between 10000W and 28000W. Check the nameplate label or manual for your specific unit - the range is wide enough that averages can mislead.
How much electricity does a tankless water heater use per day?
At around 0.5 hours of use a day and a 80% duty cycle, that works out to roughly 7.2 kWh per day, or about 216 kWh a month. Your actual figure depends on your usage and model.
Why does the cost differ so much between states?
Residential electricity rates across the US range from about 12.35 cents per kWh in North Dakota to 46.62 cents in Hawaii - nearly a fourfold difference. The same tankless water heater, used identically, therefore costs almost four times as much to run in the most expensive state as in the cheapest.
Is it cheaper to run a tankless water heater at night?
Only if you are on a time-of-use or variable tariff. On a flat rate, the time of day makes no difference to cost. If you are on time-of-use pricing, off-peak hours are typically materially cheaper, and shifting this load can reduce its cost without reducing usage.