How much does it cost to run a warm mist humidifier?
A warm mist humidifier costs about 3.8¢ per hour, 30¢ a day, $9.20 a month and $46 a year at typical use (8 hours a day for 5 months a year) and the U.S. average rate of 17.99¢/kWh. Warm mist humidifiers boil water with a 150-450 W heater. The heat does slightly warm the room, but at heater cost.
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Cost by hours of use
| Hours per day | kWh/day | Per day | Per month | Per year (all year) |
|---|---|---|---|---|
| 1 hour | 0.21 | 3.8¢ | $1.15 | $14 |
| 2 hours | 0.42 | 7.6¢ | $2.30 | $28 |
| 4 hours | 0.84 | 15¢ | $4.60 | $55 |
| 8 hours | 1.68 | 30¢ | $9.20 | $110 |
| 12 hours | 2.52 | 45¢ | $13.80 | $166 |
| 24 hours | 5.04 | 91¢ | $27.60 | $331 |
Cost to run a warm mist humidifier in every state
The same warm mist humidifier costs $31 a year in North Dakota and $111 in Hawaii, at each state's average residential rate (12 months ending July 2026).
| State | Rate | Per hour | Per month | Per year |
|---|---|---|---|---|
| North Dakota | 12.32¢ | 2.6¢ | $6.30 | $31 |
| Idaho | 12.65¢ | 2.7¢ | $6.47 | $32 |
| Nebraska | 12.86¢ | 2.7¢ | $6.58 | $33 |
| Louisiana | 12.99¢ | 2.7¢ | $6.64 | $33 |
| Utah | 13.32¢ | 2.8¢ | $6.81 | $34 |
| Nevada | 13.36¢ | 2.8¢ | $6.83 | $34 |
| Arkansas | 13.43¢ | 2.8¢ | $6.87 | $34 |
| Tennessee | 13.56¢ | 2.8¢ | $6.93 | $35 |
| Oklahoma | 13.70¢ | 2.9¢ | $7.01 | $35 |
| Montana | 13.84¢ | 2.9¢ | $7.08 | $35 |
| Kentucky | 13.92¢ | 2.9¢ | $7.12 | $36 |
| Missouri | 13.95¢ | 2.9¢ | $7.13 | $36 |
| Wyoming | 14.01¢ | 2.9¢ | $7.16 | $36 |
| Washington | 14.12¢ | 3.0¢ | $7.22 | $36 |
| Iowa | 14.13¢ | 3.0¢ | $7.23 | $36 |
| South Dakota | 14.20¢ | 3.0¢ | $7.26 | $36 |
| Mississippi | 14.77¢ | 3.1¢ | $7.55 | $38 |
| North Carolina | 14.77¢ | 3.1¢ | $7.55 | $38 |
| Kansas | 15.09¢ | 3.2¢ | $7.72 | $39 |
| Georgia | 15.12¢ | 3.2¢ | $7.73 | $39 |
| New Mexico | 15.32¢ | 3.2¢ | $7.83 | $39 |
| Florida | 15.39¢ | 3.2¢ | $7.87 | $39 |
| Arizona | 15.40¢ | 3.2¢ | $7.87 | $39 |
| West Virginia | 15.48¢ | 3.3¢ | $7.92 | $40 |
| Oregon | 15.50¢ | 3.3¢ | $7.93 | $40 |
| South Carolina | 15.64¢ | 3.3¢ | $8.00 | $40 |
| Texas | 15.96¢ | 3.4¢ | $8.16 | $41 |
| Minnesota | 16.22¢ | 3.4¢ | $8.29 | $41 |
| Alabama | 16.44¢ | 3.5¢ | $8.41 | $42 |
| Virginia | 16.48¢ | 3.5¢ | $8.43 | $42 |
| Colorado | 16.58¢ | 3.5¢ | $8.48 | $42 |
| Indiana | 16.94¢ | 3.6¢ | $8.66 | $43 |
| Delaware | 17.79¢ | 3.7¢ | $9.10 | $45 |
| Ohio | 18.25¢ | 3.8¢ | $9.33 | $47 |
| Wisconsin | 18.74¢ | 3.9¢ | $9.58 | $48 |
| Illinois | 18.79¢ | 3.9¢ | $9.61 | $48 |
| Pennsylvania | 20.70¢ | 4.3¢ | $10.58 | $53 |
| Maryland | 21.03¢ | 4.4¢ | $10.75 | $54 |
| Michigan | 21.05¢ | 4.4¢ | $10.76 | $54 |
| New Jersey | 23.78¢ | 5.0¢ | $12.16 | $61 |
| Vermont | 23.80¢ | 5.0¢ | $12.17 | $61 |
| District of Columbia | 24.20¢ | 5.1¢ | $12.37 | $62 |
| New Hampshire | 26.67¢ | 5.6¢ | $13.64 | $68 |
| Alaska | 26.85¢ | 5.6¢ | $13.73 | $69 |
| Connecticut | 27.99¢ | 5.9¢ | $14.31 | $72 |
| New York | 28.39¢ | 6.0¢ | $14.52 | $73 |
| Rhode Island | 29.27¢ | 6.1¢ | $14.97 | $75 |
| Maine | 29.31¢ | 6.2¢ | $14.99 | $75 |
| Massachusetts | 30.43¢ | 6.4¢ | $15.56 | $78 |
| California | 32.99¢ | 6.9¢ | $16.87 | $84 |
| Hawaii | 43.51¢ | 9.1¢ | $22.25 | $111 |
How to cut the cost
- Switch to cool-mist ultrasonic mode on dual models; it uses about 30 W instead of 300 W.
- Use an auto-off humidistat set to 40-45%.
- Descale the heating element weekly with vinegar; scale makes it run longer.
- Run it only in the bedroom while sleeping.
Cheaper ways to get the job done
Adds the same moisture at about 10% of the electricity.
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Compare with similar appliances
| Appliance | Watts | Typical use | Per month | Per year |
|---|---|---|---|---|
| Warm mist humidifier | 300 | 8 hours a day for 5 months a year | $9.20 | $46 |
| Humidifier | 30 | 10 hours a day for 5 months a year | $1.72 | $9 |
| Whole-house humidifier | 20 | 12 hours a day for 5 months a year | $0.66 | $3 |
| Dehumidifier | 500 | 24 hours a day for 6 months a year | $26.28 | $158 |
| Attic fan | 300 | 8 hours a day for 5 months a year | $9.20 | $46 |
| Whole house fan | 300 | 5 hours a day for 5 months a year | $8.21 | $41 |
| Drum fan | 250 | 4 hours a day, 4 days a week for 5 months a year | $3.13 | $16 |
Head-to-head comparisons
Frequently asked questions
How much does it cost to run a warm mist humidifier per hour?
A warm mist humidifier drawing 300 watts uses 0.21 kWh per hour while running (70% duty cycle). At the U.S. average of 17.99¢/kWh that's 3.8¢ per hour. In North Dakota (12.32¢) it's 2.6¢. In Hawaii (43.51¢) it's 9.1¢.
How much does it cost to run a warm mist humidifier per month?
At typical use (8 hours a day for 5 months a year), a warm mist humidifier costs about $9.20 a month while in use and $46 a year over the 5 months it's typically used, at the U.S. average rate. Enter your ZIP in the calculator above for your utility's rate.
How many watts does a warm mist humidifier use?
Most warm mist humidifiers use 150 to 450 watts. Check the label on the back or bottom for your model's exact rating.
How many kWh does a warm mist humidifier use?
About 1.68 kWh a day and 256 kWh a year at typical use (8 hours a day for 5 months a year).
Does a warm mist humidifier use a lot of electricity?
No. At about 256 kWh a year it's a small share (2.4%) of the average U.S. home's 10,492 kWh.
Is it cheaper to run a warm mist humidifier or a humidifier?
At typical use, a warm mist humidifier costs about $46 a year versus $9 for a humidifier. So the humidifier is cheaper by about $37 a year. Use the comparison table above to compare them at your own settings.
How can I lower the cost of running a warm mist humidifier?
- Switch to cool-mist ultrasonic mode on dual models; it uses about 30 W instead of 300 W.
- Use an auto-off humidistat set to 40-45%.
- Descale the heating element weekly with vinegar; scale makes it run longer.
Rates updated 2026-10-21: EIA data through July 2026. Typical wattage and usage reviewed against DOE, ENERGY STAR and manufacturer specs. Methodology.