A 3-ton central air conditioner in Kentucky costs about $77.17 in July and $259 a year at 14.20¢/kWh; an 8,000 BTU window unit about $16.10 in July.
At 14.20¢/kWh — Kentucky average, Jan–Aug 2026 (EIA). That is 22% below the U.S. average of 18.19¢.
| Efficiency | Per year | vs yours |
|---|---|---|
| SEER2 13.4 (min · North) | $276 | +$17.39 |
| SEER2 14.3 (min · South) | $259 | — |
| SEER2 15.2 (ENERGY STAR) | $244 | −$15.33 |
| SEER2 17 (ES average) | $218 | −$41.11 |
| Month | Full-load hours | 3-ton central | 8,000 BTU window |
|---|---|---|---|
| March | 5 | $1.76 | $0.37 |
| April | 7 | $2.43 | $0.51 |
| May | 58 | $20.73 | $4.32 |
| June | 142 | $50.71 | $10.58 |
| July | 216 | $77.17 | $16.10 |
| August | 188 | $67.25 | $14.03 |
| September | 91 | $32.41 | $6.76 |
| October | 16 | $5.73 | $1.20 |
DOE's room-AC test assumes 750 full-load hours a year for a typical U.S. home. We scale it by Kentucky's population-weighted cooling degree days (1,174 ÷ 1,216) and spread it over the months the same way: 724 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. × 724 h = 1,823 kWh × 14.20¢ = $259.
The full method, material data and tips are on the main air conditioner cost calculator page.