💧 Water, Pool & Spa
How Much Does a Tankless Electric Water Heater Cost to Run?
At the current U.S. average rate of 18.4¢/kWh (May 2026), a tankless electric water heater costs about $70.48 per month at typical usage — 0.7 hours/day.
Per hour
$3.31
at 13,000–27,000 W
Per day
$2.32
0.7 hours/day
Per month
$70.48
383 kWh
Per year
$846
4,599 kWh
Whole-house electric tankless units draw a startling 13–27 kW while a tap runs — often the largest instantaneous load in the house — but only run during actual hot-water use. Total monthly energy usually lands modestly below an equivalent tank by eliminating standby losses.
Calculate it for your home
Per hour
$3.31
Per day
$2.32
Per month
$70.48
Per year
$846
Uses 383 kWh/month at 18.4¢ per kWh.
Cheapest and most expensive states
Monthly cost at typical usage, using each state's current average residential rate.
Cost in every state
| State | Rate (¢/kWh) | Per hour | Per month | Per year |
|---|---|---|---|---|
| Idaho | 12.4 | $2.23 | $47.50 | $570 |
| Utah | 13.0 | $2.34 | $49.80 | $598 |
| Oklahoma | 13.4 | $2.41 | $51.33 | $616 |
| Nebraska | 13.6 | $2.45 | $52.09 | $625 |
| Nevada | 13.6 | $2.45 | $52.09 | $625 |
| North Dakota | 13.6 | $2.45 | $52.09 | $625 |
| Missouri | 13.7 | $2.47 | $52.48 | $630 |
| Iowa | 14.1 | $2.54 | $54.01 | $648 |
| New Mexico | 14.1 | $2.54 | $54.01 | $648 |
| Louisiana | 14.2 | $2.56 | $54.39 | $653 |
| Arkansas | 14.4 | $2.59 | $55.16 | $662 |
| Tennessee | 14.5 | $2.61 | $55.54 | $667 |
| Montana | 14.7 | $2.65 | $56.31 | $676 |
| Wyoming | 14.8 | $2.66 | $56.69 | $681 |
| Kentucky | 15.0 | $2.70 | $57.46 | $690 |
| Washington | 15.0 | $2.70 | $57.46 | $690 |
| Kansas | 15.1 | $2.72 | $57.84 | $694 |
| North Carolina | 15.1 | $2.72 | $57.84 | $694 |
| Arizona | 15.2 | $2.74 | $58.22 | $699 |
| Florida | 15.2 | $2.74 | $58.22 | $699 |
| South Dakota | 15.7 | $2.83 | $60.14 | $722 |
| Georgia | 15.8 | $2.84 | $60.52 | $727 |
| Colorado | 16.2 | $2.92 | $62.05 | $745 |
| Mississippi | 16.2 | $2.92 | $62.05 | $745 |
| South Carolina | 16.2 | $2.92 | $62.05 | $745 |
| Oregon | 16.3 | $2.93 | $62.44 | $750 |
| Texas | 16.4 | $2.95 | $62.82 | $754 |
| Alabama | 16.8 | $3.02 | $64.35 | $773 |
| West Virginia | 16.8 | $3.02 | $64.35 | $773 |
| Minnesota | 17.0 | $3.06 | $65.12 | $782 |
| Virginia | 17.6 | $3.17 | $67.42 | $809 |
| Indiana | 18.2 | $3.28 | $69.71 | $837 |
| Delaware | 19.4 | $3.49 | $74.31 | $892 |
| Ohio | 19.5 | $3.51 | $74.69 | $897 |
| Wisconsin | 19.7 | $3.55 | $75.46 | $906 |
| Pennsylvania | 21.6 | $3.89 | $82.74 | $993 |
| Maryland | 21.8 | $3.92 | $83.50 | $1,003 |
| Michigan | 22.0 | $3.96 | $84.27 | $1,012 |
| New Jersey | 23.3 | $4.19 | $89.25 | $1,072 |
| Illinois | 23.9 | $4.30 | $91.55 | $1,099 |
| Vermont | 24.9 | $4.48 | $95.38 | $1,145 |
| Washington, D.C. | 25.4 | $4.57 | $97.29 | $1,168 |
| New Hampshire | 27.3 | $4.91 | $105 | $1,256 |
| Connecticut | 27.4 | $4.93 | $105 | $1,260 |
| Alaska | 28.2 | $5.08 | $108 | $1,297 |
| Maine | 28.6 | $5.15 | $110 | $1,315 |
| Massachusetts | 28.8 | $5.18 | $110 | $1,325 |
| Rhode Island | 29.5 | $5.31 | $113 | $1,357 |
| New York | 29.9 | $5.38 | $115 | $1,375 |
| California | 33.3 | $5.99 | $128 | $1,531 |
| Hawaii | 52.0 | $9.36 | $199 | $2,391 |
How to lower the cost
- Set water heaters to 120°F and fix dripping hot taps quickly — a drip is a slow leak of paid heat.
- Shorter showers and low-flow heads cut costs directly; hot water is usually a top-three energy use.
- Timers and covers transform pool, spa, and tank costs — stored heat and off-hours running are much cheaper.
Frequently asked questions
How much electricity does a tankless electric water heater use?
A typical tankless electric water heater draws about 18,000 watts in use. At 0.7 hours/day, that works out to roughly 13 kWh per day, or 383 kWh per month.
How much does it cost to run a tankless electric water heater for 1 hour?
At the current U.S. average residential rate of 18.4¢/kWh, one hour costs about $3.31. In Idaho (12.4¢/kWh) it's $2.23, while in Hawaii (52¢/kWh) it's $9.36.
How much does a tankless electric water heater cost to run per month?
With typical usage (0.7 hours/day), expect about $70.48 per month at the U.S. average rate — from $47.50 in Idaho up to $199 in Hawaii. Rates are as of May 2026.
Does a tankless electric water heater use a lot of electricity?
Yes — at typical usage it accounts for roughly 43% of an average U.S. home's monthly consumption (885 kWh), which makes it one of the larger loads in the house.