Data through June 2026
Running cost · Water Heaters (Electric) · ENERGY STAR certified
Carnot Labs, Inc. N51
Heating a typical household's hot water, the Carnot Labs, Inc. N51 is certified at 1,404 kWh a year — about $257 at the U.S. average electricity rate, or $21.46 a month. It sits near the bottom of the certified table — using 16% more than the median electric water heater (rank 480 of 510) — so the state you live in matters more than usual. Where you live moves the bill from $184 a year in Nevada to $740 in Hawaii.
Dimensions 44.2" H × 18.9" W
Estimated annual running cost · U.S. average rate 18.3¢/kWh
$257/yr
- Per month
- $21.46
- Per day
- 71¢
- Certified use
- 1,404 kWh/yr
- Type
- Hybrid/Electric Heat Pump
- Heat pump type
- 240 Volt Integrated HPWH
- Storage volume
- 47 gal
- First-hour rating
- 75 gal
- UEF
- 3.53
What it costs in every state
| State | Rate ¢/kWh | This model $/yr | Relative cost |
|---|---|---|---|
| Alabama | 16.4¢ | $230 | |
| Alaska | 28.2¢ | $396 | |
| Arizona | 15.2¢ | $213 | |
| Arkansas | 14.1¢ | $198 | |
| California | 34.7¢ | $488 | |
| Colorado | 17.1¢ | $241 | |
| Connecticut | 24.3¢ | $341 | |
| Delaware | 19.3¢ | $271 | |
| District of Columbia | 24.4¢ | $342 | |
| Florida | 15.1¢ | $212 | |
| Georgia | 16.4¢ | $230 | |
| Hawaiipriciest | 52.7¢ | $740 | |
| Idaho | 14.4¢ | $202 | |
| Illinois | 19.9¢ | $279 | |
| Indiana | 17.5¢ | $246 | |
| Iowa | 15.9¢ | $224 | |
| Kansas | 15.7¢ | $221 | |
| Kentucky | 14.3¢ | $200 | |
| Louisiana | 13.5¢ | $189 | |
| Maine | 29.6¢ | $415 | |
| Maryland | 21.8¢ | $307 | |
| Massachusetts | 29.6¢ | $416 | |
| Michigan | 23.0¢ | $323 | |
| Minnesota | 17.5¢ | $246 | |
| Mississippi | 14.9¢ | $209 | |
| Missouri | 16.2¢ | $228 | |
| Montana | 15.1¢ | $213 | |
| Nebraska | 13.3¢ | $186 | |
| Nevadacheapest | 13.1¢ | $184 | |
| New Hampshire | 27.0¢ | $379 | |
| New Jersey | 24.9¢ | $350 | |
| New Mexico | 15.1¢ | $211 | |
| New York | 29.5¢ | $414 | |
| North Carolina | 14.7¢ | $207 | |
| North Dakota | 14.1¢ | $198 | |
| Ohio | 19.2¢ | $269 | |
| Oklahoma | 14.3¢ | $201 | |
| Oregon | 16.3¢ | $229 | |
| Pennsylvania | 21.7¢ | $305 | |
| Rhode Island | 29.2¢ | $410 | |
| South Carolina | 15.6¢ | $218 | |
| South Dakota | 15.4¢ | $216 | |
| Tennessee | 14.1¢ | $198 | |
| Texas | 15.9¢ | $224 | |
| Utah | 13.4¢ | $188 | |
| Vermont | 24.4¢ | $343 | |
| Virginia | 17.2¢ | $242 | |
| Washington | 14.9¢ | $209 | |
| West Virginia | 15.4¢ | $217 | |
| Wisconsin | 19.6¢ | $275 | |
| Wyoming | 15.2¢ | $214 |
Certified models closest in efficiency
| Model | kWh/yr | $/yr (US avg) |
|---|---|---|
| Friedrich PROH80 T0 FD120-M | 1,403 | $257 |
| Friedrich PROH80 T0 FD120-MSO | 1,403 | $257 |
| Rheem PROPH80 T0 RH120-M | 1,403 | $257 |
| Rheem PROPH80 T0 RH120-MSO | 1,403 | $257 |
| Rheem XE80T10HM00U0 | 1,403 | $257 |
| Rheem XE80T10HMS00U0 | 1,403 | $257 |
Run your own numbers
Your rate, your numbers
- Per day
- 71¢
- Per month
- $21.46
- Per year
- $257
1,404 kWh/yr × 18.3¢/kWh = $257/yr
Prefilled with this model's certified 1,404 kWh/yr — adjust if your usage differs from the DOE test basis. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.
Questions, answered with the data
- How much electricity does the Carnot Labs, Inc. N51 use?
- ENERGY STAR certifies the Carnot Labs, Inc. N51 at 1,404 kWh per year. The certified annual kWh comes from the DOE Uniform Energy Factor test, which simulates a typical household's daily hot-water draw pattern. Only electric models (including heat-pump units) are listed — gas models burn gas, not kWh.
- How much does the Carnot Labs, Inc. N51 cost to run per month?
- About $21.46 a month at the U.S. average residential rate (18.3¢/kWh) — 71¢ a day, or $257 a year. Your state's rate moves this up or down; see the table above.
- Is the Carnot Labs, Inc. N51 energy efficient?
- It uses 16% more electricity than the median certified electric water heater, which puts it among the least efficient certified models.
- What does the Carnot Labs, Inc. N51 cost to run in the cheapest vs. priciest state?
- At current residential rates it costs about $184 a year in Nevada (13.1¢/kWh) and $740 in Hawaii (52.7¢/kWh).