❄️ Cooling & Air
How Much Does a Evaporative (Swamp) Cooler Cost to Run?
At the current U.S. average rate of 18.8¢/kWh (April 2026), a evaporative (swamp) cooler costs about $18.29 per month at typical usage — 8 hours/day.
Per hour
7.5¢
at 100–800 W
Per day
$0.60
8 hours/day
Per month
$18.29
97 kWh
Per year
$220
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
7.5¢
Per day
$0.60
Per month
$18.29
Per year
$220
Uses 97 kWh/month at 18.8¢ 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 |
|---|---|---|---|---|
| North Dakota | 12.4 | 5.0¢ | $12.06 | $145 |
| Idaho | 12.7 | 5.1¢ | $12.35 | $148 |
| Nebraska | 13.3 | 5.3¢ | $12.94 | $155 |
| Oklahoma | 13.3 | 5.3¢ | $12.94 | $155 |
| Utah | 13.3 | 5.3¢ | $12.94 | $155 |
| Iowa | 13.9 | 5.6¢ | $13.52 | $162 |
| Montana | 13.9 | 5.6¢ | $13.52 | $162 |
| Missouri | 14.0 | 5.6¢ | $13.62 | $164 |
| Arkansas | 14.2 | 5.7¢ | $13.81 | $166 |
| Nevada | 14.3 | 5.7¢ | $13.91 | $167 |
| Louisiana | 14.4 | 5.8¢ | $14.01 | $168 |
| Washington | 14.4 | 5.8¢ | $14.01 | $168 |
| South Dakota | 14.5 | 5.8¢ | $14.11 | $169 |
| Wyoming | 14.7 | 5.9¢ | $14.30 | $172 |
| Tennessee | 14.9 | 6.0¢ | $14.49 | $174 |
| Kentucky | 15.0 | 6.0¢ | $14.59 | $175 |
| New Mexico | 15.2 | 6.1¢ | $14.79 | $178 |
| Florida | 15.4 | 6.2¢ | $14.98 | $180 |
| Georgia | 15.4 | 6.2¢ | $14.98 | $180 |
| Arizona | 15.5 | 6.2¢ | $15.08 | $181 |
| Kansas | 15.8 | 6.3¢ | $15.37 | $185 |
| Oregon | 15.8 | 6.3¢ | $15.37 | $185 |
| West Virginia | 16.1 | 6.4¢ | $15.66 | $188 |
| North Carolina | 16.3 | 6.5¢ | $15.86 | $190 |
| Minnesota | 16.4 | 6.6¢ | $15.95 | $192 |
| Colorado | 16.5 | 6.6¢ | $16.05 | $193 |
| Mississippi | 16.8 | 6.7¢ | $16.34 | $196 |
| Texas | 17.0 | 6.8¢ | $16.54 | $199 |
| South Carolina | 17.1 | 6.8¢ | $16.63 | $200 |
| Alabama | 17.4 | 7.0¢ | $16.93 | $203 |
| Virginia | 17.4 | 7.0¢ | $16.93 | $203 |
| Indiana | 17.9 | 7.2¢ | $17.41 | $209 |
| Delaware | 18.8 | 7.5¢ | $18.29 | $220 |
| Wisconsin | 19.2 | 7.7¢ | $18.68 | $224 |
| Ohio | 19.5 | 7.8¢ | $18.97 | $228 |
| Illinois | 20.5 | 8.2¢ | $19.94 | $239 |
| Michigan | 21.4 | 8.6¢ | $20.82 | $250 |
| Pennsylvania | 21.5 | 8.6¢ | $20.92 | $251 |
| Maryland | 22.1 | 8.8¢ | $21.50 | $258 |
| New Jersey | 23.5 | 9.4¢ | $22.86 | $274 |
| Vermont | 24.6 | $0.10 | $23.93 | $287 |
| Washington, D.C. | 25.4 | $0.10 | $24.71 | $297 |
| New Hampshire | 27.2 | $0.11 | $26.46 | $318 |
| Alaska | 27.4 | $0.11 | $26.65 | $320 |
| Rhode Island | 28.3 | $0.11 | $27.53 | $331 |
| Maine | 28.4 | $0.11 | $27.63 | $332 |
| Massachusetts | 29.5 | $0.12 | $28.70 | $345 |
| New York | 29.5 | $0.12 | $28.70 | $345 |
| Connecticut | 32.2 | $0.13 | $31.32 | $376 |
| California | 35.3 | $0.14 | $34.34 | $412 |
| Hawaii | 46.6 | $0.19 | $45.33 | $544 |
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 18.8¢/kWh, one hour costs about 7.5¢. In North Dakota (12.4¢/kWh) it's 5.0¢, while in Hawaii (46.6¢/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 $18.29 per month at the U.S. average rate — from $12.06 in North Dakota up to $45.33 in Hawaii. Rates are as of April 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.