❄️ Cooling & Air
How Much Does a Evaporative (Swamp) Cooler Cost to Run?
At the current U.S. average rate of 18.4¢/kWh (May 2026), a evaporative (swamp) cooler costs about $17.90 per month at typical usage — 8 hours/day.
Per hour
7.4¢
at 100–800 W
Per day
$0.59
8 hours/day
Per month
$17.90
97 kWh
Per year
$215
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
7.4¢
Per day
$0.59
Per month
$17.90
Per year
$215
Uses 97 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 | 5.0¢ | $12.06 | $145 |
| Utah | 13.0 | 5.2¢ | $12.65 | $152 |
| Oklahoma | 13.4 | 5.4¢ | $13.04 | $157 |
| Nebraska | 13.6 | 5.4¢ | $13.23 | $159 |
| Nevada | 13.6 | 5.4¢ | $13.23 | $159 |
| North Dakota | 13.6 | 5.4¢ | $13.23 | $159 |
| Missouri | 13.7 | 5.5¢ | $13.33 | $160 |
| Iowa | 14.1 | 5.6¢ | $13.72 | $165 |
| New Mexico | 14.1 | 5.6¢ | $13.72 | $165 |
| Louisiana | 14.2 | 5.7¢ | $13.81 | $166 |
| Arkansas | 14.4 | 5.8¢ | $14.01 | $168 |
| Tennessee | 14.5 | 5.8¢ | $14.11 | $169 |
| Montana | 14.7 | 5.9¢ | $14.30 | $172 |
| Wyoming | 14.8 | 5.9¢ | $14.40 | $173 |
| Kentucky | 15.0 | 6.0¢ | $14.59 | $175 |
| Washington | 15.0 | 6.0¢ | $14.59 | $175 |
| Kansas | 15.1 | 6.0¢ | $14.69 | $176 |
| North Carolina | 15.1 | 6.0¢ | $14.69 | $176 |
| Arizona | 15.2 | 6.1¢ | $14.79 | $178 |
| Florida | 15.2 | 6.1¢ | $14.79 | $178 |
| South Dakota | 15.7 | 6.3¢ | $15.27 | $183 |
| Georgia | 15.8 | 6.3¢ | $15.37 | $185 |
| Colorado | 16.2 | 6.5¢ | $15.76 | $189 |
| Mississippi | 16.2 | 6.5¢ | $15.76 | $189 |
| South Carolina | 16.2 | 6.5¢ | $15.76 | $189 |
| Oregon | 16.3 | 6.5¢ | $15.86 | $190 |
| Texas | 16.4 | 6.6¢ | $15.95 | $192 |
| Alabama | 16.8 | 6.7¢ | $16.34 | $196 |
| West Virginia | 16.8 | 6.7¢ | $16.34 | $196 |
| Minnesota | 17.0 | 6.8¢ | $16.54 | $199 |
| Virginia | 17.6 | 7.0¢ | $17.12 | $206 |
| Indiana | 18.2 | 7.3¢ | $17.70 | $213 |
| Delaware | 19.4 | 7.8¢ | $18.87 | $227 |
| Ohio | 19.5 | 7.8¢ | $18.97 | $228 |
| Wisconsin | 19.7 | 7.9¢ | $19.16 | $230 |
| Pennsylvania | 21.6 | 8.6¢ | $21.01 | $252 |
| Maryland | 21.8 | 8.7¢ | $21.21 | $255 |
| Michigan | 22.0 | 8.8¢ | $21.40 | $257 |
| New Jersey | 23.3 | 9.3¢ | $22.67 | $272 |
| Illinois | 23.9 | $0.10 | $23.25 | $279 |
| Vermont | 24.9 | $0.10 | $24.22 | $291 |
| Washington, D.C. | 25.4 | $0.10 | $24.71 | $297 |
| New Hampshire | 27.3 | $0.11 | $26.56 | $319 |
| Connecticut | 27.4 | $0.11 | $26.65 | $320 |
| Alaska | 28.2 | $0.11 | $27.43 | $329 |
| Maine | 28.6 | $0.11 | $27.82 | $334 |
| Massachusetts | 28.8 | $0.12 | $28.02 | $336 |
| Rhode Island | 29.5 | $0.12 | $28.70 | $345 |
| New York | 29.9 | $0.12 | $29.09 | $349 |
| California | 33.3 | $0.13 | $32.39 | $389 |
| Hawaii | 52.0 | $0.21 | $50.59 | $607 |
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 18.4¢/kWh, one hour costs about 7.4¢. In Idaho (12.4¢/kWh) it's 5.0¢, while in Hawaii (52¢/kWh) it's $0.21.
How much does a evaporative (swamp) cooler cost to run per month?
With typical usage (8 hours/day), expect about $17.90 per month at the U.S. average rate — from $12.06 in Idaho up to $50.59 in Hawaii. Rates are as of May 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.