❄️ Cooling & Air
How Much Does a Evaporative (Swamp) Cooler Cost to Run?
At the current U.S. average rate of 18.3¢/kWh (July 2026), a evaporative (swamp) cooler costs about $17.80 per month at typical usage — 8 hours/day.
Per hour
7.3¢
at 100–800 W
Per day
$0.59
8 hours/day
Per month
$17.80
97 kWh
Per year
$214
1,168 kWh
In dry climates, evaporative coolers deliver whole-room cooling for fan-level wattage — typically 100–800 watts, a quarter or less of comparable AC. The tradeoff is water use and poor performance anywhere humid.
Calculate it for your home
Per hour
7.3¢
Per day
$0.59
Per month
$17.80
Per year
$214
Uses 97 kWh/month at 18.3¢ 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 |
|---|---|---|---|---|
| Louisiana | 12.7 | 5.1¢ | $12.35 | $148 |
| Nevada | 12.8 | 5.1¢ | $12.45 | $150 |
| Utah | 13.1 | 5.2¢ | $12.74 | $153 |
| North Dakota | 13.4 | 5.4¢ | $13.04 | $157 |
| Idaho | 13.7 | 5.5¢ | $13.33 | $160 |
| Tennessee | 13.7 | 5.5¢ | $13.33 | $160 |
| Kentucky | 13.8 | 5.5¢ | $13.42 | $161 |
| Nebraska | 13.8 | 5.5¢ | $13.42 | $161 |
| Arkansas | 14.3 | 5.7¢ | $13.91 | $167 |
| Oklahoma | 14.4 | 5.8¢ | $14.01 | $168 |
| Wyoming | 14.4 | 5.8¢ | $14.01 | $168 |
| Mississippi | 14.5 | 5.8¢ | $14.11 | $169 |
| Washington | 14.7 | 5.9¢ | $14.30 | $172 |
| Florida | 15.0 | 6.0¢ | $14.59 | $175 |
| Montana | 15.0 | 6.0¢ | $14.59 | $175 |
| North Carolina | 15.2 | 6.1¢ | $14.79 | $178 |
| Kansas | 15.3 | 6.1¢ | $14.88 | $179 |
| Arizona | 15.4 | 6.2¢ | $14.98 | $180 |
| South Dakota | 15.4 | 6.2¢ | $14.98 | $180 |
| South Carolina | 15.5 | 6.2¢ | $15.08 | $181 |
| West Virginia | 15.8 | 6.3¢ | $15.37 | $185 |
| Texas | 15.9 | 6.4¢ | $15.47 | $186 |
| Iowa | 16.0 | 6.4¢ | $15.56 | $187 |
| Oregon | 16.0 | 6.4¢ | $15.56 | $187 |
| Missouri | 16.1 | 6.4¢ | $15.66 | $188 |
| New Mexico | 16.1 | 6.4¢ | $15.66 | $188 |
| Georgia | 16.3 | 6.5¢ | $15.86 | $190 |
| Alabama | 16.4 | 6.6¢ | $15.95 | $192 |
| Indiana | 16.7 | 6.7¢ | $16.25 | $195 |
| Colorado | 17.0 | 6.8¢ | $16.54 | $199 |
| Minnesota | 17.5 | 7.0¢ | $17.02 | $204 |
| Virginia | 17.6 | 7.0¢ | $17.12 | $206 |
| Delaware | 18.5 | 7.4¢ | $18.00 | $216 |
| Wisconsin | 19.1 | 7.6¢ | $18.58 | $223 |
| Illinois | 19.2 | 7.7¢ | $18.68 | $224 |
| Ohio | 19.5 | 7.8¢ | $18.97 | $228 |
| Maryland | 21.4 | 8.6¢ | $20.82 | $250 |
| Pennsylvania | 21.7 | 8.7¢ | $21.11 | $253 |
| Michigan | 23.1 | 9.2¢ | $22.47 | $270 |
| Vermont | 23.8 | $0.10 | $23.15 | $278 |
| Connecticut | 24.2 | $0.10 | $23.54 | $283 |
| Washington, D.C. | 25.2 | $0.10 | $24.51 | $294 |
| New Jersey | 25.2 | $0.10 | $24.51 | $294 |
| New Hampshire | 26.6 | $0.11 | $25.88 | $311 |
| Rhode Island | 28.3 | $0.11 | $27.53 | $331 |
| Alaska | 28.8 | $0.12 | $28.02 | $336 |
| New York | 29.9 | $0.12 | $29.09 | $349 |
| Massachusetts | 30.5 | $0.12 | $29.67 | $356 |
| Maine | 32.4 | $0.13 | $31.52 | $378 |
| California | 33.6 | $0.13 | $32.69 | $392 |
| Hawaii | 48.0 | $0.19 | $46.69 | $561 |
How to lower the cost
- Raise the setpoint and add air movement — a fan makes a room feel several degrees cooler for pennies.
- Clean filters and outdoor coils each season; restricted airflow raises wattage for the same cooling.
- Close blinds on sun-facing windows during the day — blocked solar gain is cooling you don’t pay for.
Frequently asked questions
How much electricity does a evaporative (swamp) cooler use?
A typical evaporative (swamp) cooler draws about 400 watts in use. At 8 hours/day, that works out to roughly 3.2 kWh per day, or 97 kWh per month.
How much does it cost to run a evaporative (swamp) cooler for 1 hour?
At the current U.S. average residential rate of 18.3¢/kWh, one hour costs about 7.3¢. In Louisiana (12.7¢/kWh) it's 5.1¢, while in Hawaii (48¢/kWh) it's $0.19.
How much does a evaporative (swamp) cooler cost to run per month?
With typical usage (8 hours/day), expect about $17.80 per month at the U.S. average rate — from $12.35 in Louisiana up to $46.69 in Hawaii. Rates are as of July 2026.
Does a evaporative (swamp) cooler use a lot of electricity?
Yes — at typical usage it accounts for roughly 11% of an average U.S. home's monthly consumption (885 kWh), which makes it one of the larger loads in the house.