A 3-ton central air conditioner in Ohio costs about $76.36 in July and $230 a year at 18.81¢/kWh; an 8,000 BTU window unit about $14.93 in July.
At 18.81¢/kWh — Ohio average, Jan–Aug 2026 (EIA). That is 3% above the U.S. average of 18.19¢.
| Efficiency | Per year | vs yours |
|---|---|---|
| SEER2 13.4 (min · North) | $230 | — |
| SEER2 14.3 (min · South) | $216 | −$14.48 |
| SEER2 15.2 (ENERGY STAR) | $203 | −$27.24 |
| SEER2 17 (ES average) | $181 | −$48.71 |
| Month | Full-load hours | 3-ton central | 8,000 BTU window |
|---|---|---|---|
| April | 1 | $0.62 | $0.12 |
| May | 35 | $17.77 | $3.47 |
| June | 92 | $46.44 | $9.08 |
| July | 151 | $76.36 | $14.93 |
| August | 123 | $62.34 | $12.19 |
| September | 46 | $23.06 | $4.51 |
| October | 6 | $3.12 | $0.61 |
DOE's room-AC test assumes 750 full-load hours a year for a typical U.S. home. We scale it by Ohio's population-weighted cooling degree days (738 ÷ 1,216) and spread it over the months the same way: 455 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 13.4 = 2,687 W. × 455 h = 1,223 kWh × 18.81¢ = $230.
The full method, material data and tips are on the main air conditioner cost calculator page.