How Much Does It Cost to Run an Evaporative (Swamp) Cooler in North Carolina? (2026)
An evaporative cooler is only a fan and a small pump, so it uses a quarter or less of the electricity of an air conditioner of similar cooling capacity. It only works well in dry climates.
A typical evaporative (swamp) cooler (300 W) costs $0.044 per hour, or about $10.61 per month at 8 hours a day in North Carolina. Average running cost
| Wattage | Per hour | Per day | Per month | Per year |
|---|---|---|---|---|
| Low 100 W | $0.015 | $0.12 | $3.54 | $14.15 |
| Typical 300 W | $0.044 | $0.35 | $10.61 | $42.45 |
| High 800 W | $0.12 | $0.94 | $28.30 | $113.20 |
Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 8 h/day for about 120 days a year (the cooling season) ≈ 288 kWh per year.
One hour of an evaporative (swamp) cooler (0.30 kWh) is the same electricity as
- 2.1minutes of electric shower
- 3.0hours of TV
- 20phone charges
- 33hours of an LED bulb
In North Carolina, with electricity at 14.7¢ per kWh (source: EIA Table 5.6.A, 2026-06), a typical evaporative (swamp) cooler costs $0.044 per hour and about $42.45 per year at 8 hours a day. That is about 20% less than the national average for the US ($13.20 per month), because electricity in North Carolina costs 14.7¢ per kWh against 18.3¢ nationally. Each $1.00 of electricity buys roughly 22.6 hours of use.
How to lower the cost of running an evaporative (swamp) cooler
- Open a window on the far side of the room. Swamp coolers need airflow out to work.
- Replace pads each season. Clogged pads cut cooling and make the fan work harder.
- Run the pump a few minutes before the fan so pads are wet from the start.
Frequently asked questions
Is a swamp cooler cheaper to run than AC?
Yes, typically 3 to 5 times cheaper per hour, but it cannot cool a humid room.
How much water does an evaporative cooler use?
Around 10 to 25 litres per hour for a whole-house unit, less for portable ones.
Can I run a swamp cooler all day?
Yes. At 300 watts, 24 hours uses 7.2 kWh, about the same as an AC running two to three hours.
Cost by region
US states
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Canadian provinces
Related appliances
- Electric Blanket100 W typical
- Heat Pump (Ducted or Mini-Split)2,000 W typical
- Baseboard Heater1,500 W typical
- Portable Fan (Box or Pedestal)50 W typical
Use the generic electricity cost calculator · Which uses more? Take the quiz