A 3-ton central air conditioner in Louisiana costs about $109.00 in July and $531 a year at 13.27¢/kWh; an 8,000 BTU window unit about $22.74 in July.
At 13.27¢/kWh — Louisiana average, Jan–Aug 2026 (EIA). That is 27% below the U.S. average of 18.19¢.
| Efficiency | Per year | vs yours |
|---|---|---|
| SEER2 13.4 (min · North) | $566 | +$35.64 |
| SEER2 14.3 (min · South) | $531 | — |
| SEER2 15.2 (ENERGY STAR) | $499 | −$31.42 |
| SEER2 17 (ES average) | $446 | −$84.27 |
| Month | Full-load hours | 3-ton central | 8,000 BTU window |
|---|---|---|---|
| January | 17 | $5.56 | $1.16 |
| February | 12 | $4.12 | $0.86 |
| March | 35 | $11.54 | $2.41 |
| April | 67 | $22.25 | $4.64 |
| May | 176 | $58.72 | $12.25 |
| June | 274 | $91.69 | $19.13 |
| July | 326 | $109.00 | $22.74 |
| August | 319 | $106.73 | $22.27 |
| September | 231 | $77.06 | $16.08 |
| October | 94 | $31.32 | $6.53 |
| November | 28 | $9.27 | $1.93 |
| December | 10 | $3.30 | $0.69 |
DOE's room-AC test assumes 750 full-load hours a year for a typical U.S. home. We scale it by Louisiana's population-weighted cooling degree days (2,575 ÷ 1,216) and spread it over the months the same way: 1,588 hours a year. Your thermostat setting and insulation move this a lot — switch the calculator to your own hours if you know them.
3 tons = 36,000 BTU/h ÷ SEER2 14.3 = 2,517 W. × 1,588 h = 3,998 kWh × 13.27¢ = $531.
The full method, material data and tips are on the main air conditioner cost calculator page.