Electric tankless water heater: electricity cost calculator
Quick answer: a typical electric tankless water heater costs about $101/month while in use at the U.S. average electricity price (18.44¢/kWh) — about $1212 per year. Your number depends on wattage, runtime and your state — calculate it below.
Whole-home electric tankless units draw 9–27 kW while heating flowing water — the largest instantaneous load in a house. Total energy is similar to a well-insulated tank because there are no standby losses; the preset models about an hour of combined daily flow.
18.00 kWh/day used · 548 kWh/month in use · 6575 kWh/year at 18.44¢ per kWh
Low, typical and heavy use
Monthly cost while in use, at the U.S. average price of 18.44¢/kWh.
| Scenario | Watts | Hours/day | Per month |
|---|---|---|---|
| Light use | 9,000 W | 0.6 h | $30.31 |
| Typical | 18,000 W | 1.0 h | $101.03 |
| Heavy use | 27,000 W | 1.5 h | $227.31 |
Common questions
Is tankless cheaper to run than a tank?
Modestly — eliminating standby losses saves roughly 5–15% for typical households. The bigger consideration is the electrical service upgrade a 27 kW unit often requires.
Cost in every state
Monthly cost of a typical electric tankless water heater (18,000 W, 1h/day) at each state's average residential price, May 2026.
| State | Avg price | Per month |
|---|---|---|
| Alabama | 16.77¢ | $91.88 |
| Alaska | 28.23¢ | $154.67 |
| Arizona | 15.23¢ | $83.44 |
| Arkansas | 14.36¢ | $78.67 |
| California | 33.25¢ | $182.17 |
| Colorado | 16.16¢ | $88.54 |
| Connecticut | 27.37¢ | $149.95 |
| Delaware | 19.38¢ | $106.18 |
| District of Columbia | 25.40¢ | $139.16 |
| Florida | 15.17¢ | $83.11 |
| Georgia | 15.84¢ | $86.78 |
| Hawaii | 52.00¢ | $284.89 |
| Idaho | 12.35¢ | $67.66 |
| Illinois | 23.85¢ | $130.67 |
| Indiana | 18.15¢ | $99.44 |
| Iowa | 14.14¢ | $77.47 |
| Kansas | 15.13¢ | $82.89 |
| Kentucky | 14.98¢ | $82.07 |
| Louisiana | 14.15¢ | $77.52 |
| Maine | 28.63¢ | $156.86 |
| Maryland | 21.77¢ | $119.27 |
| Massachusetts | 28.82¢ | $157.90 |
| Michigan | 22.01¢ | $120.59 |
| Minnesota | 16.95¢ | $92.86 |
| Mississippi | 16.16¢ | $88.54 |
| Missouri | 13.68¢ | $74.95 |
| Montana | 14.67¢ | $80.37 |
| Nebraska | 13.59¢ | $74.46 |
| Nevada | 13.60¢ | $74.51 |
| New Hampshire | 27.33¢ | $149.73 |
| New Jersey | 23.27¢ | $127.49 |
| New Mexico | 14.12¢ | $77.36 |
| New York | 29.93¢ | $163.98 |
| North Carolina | 15.09¢ | $82.67 |
| North Dakota | 13.61¢ | $74.57 |
| Ohio | 19.52¢ | $106.95 |
| Oklahoma | 13.38¢ | $73.31 |
| Oregon | 16.27¢ | $89.14 |
| Pennsylvania | 21.55¢ | $118.07 |
| Rhode Island | 29.46¢ | $161.40 |
| South Carolina | 16.18¢ | $88.65 |
| South Dakota | 15.73¢ | $86.18 |
| Tennessee | 14.47¢ | $79.28 |
| Texas | 16.44¢ | $90.07 |
| Utah | 12.96¢ | $71.00 |
| Vermont | 24.89¢ | $136.37 |
| Virginia | 17.61¢ | $96.48 |
| Washington | 14.95¢ | $81.91 |
| West Virginia | 16.80¢ | $92.04 |
| Wisconsin | 19.74¢ | $108.15 |
| Wyoming | 14.80¢ | $81.09 |
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Methodology & sources
Cost = watts ÷ 1,000 × hours × price per kWh. Electricity prices are average residential prices by state from the EIA Electric Power Monthly, Table 5.6.A (May 2026). EIA averages include delivery charges and taxes but are not any specific utility tariff — for an exact figure, use the rate from your own bill. Wattage presets reflect common product ranges; check your appliance's nameplate or a plug-in power meter for its true draw.
Last verified: July 30, 2026. Prices refresh automatically each month when EIA publishes new data.