A 2-ton central air conditioner draws about 1.68 kW and costs $0.31 an hour running — about $229 over a 750-hour U.S.-average cooling year at 18.19¢/kWh.
At 18.19¢/kWh — U.S. average, Jan–Aug 2026 (EIA).
| Efficiency | Per year | vs yours |
|---|---|---|
| SEER2 13.4 (min · North) | $244 | +$15.38 |
| SEER2 14.3 (min · South) | $229 | — |
| SEER2 15.2 (ENERGY STAR) | $215 | −$13.56 |
| SEER2 17 (ES average) | $193 | −$36.37 |
| Size | Efficiency | Watts | Per hour | Per year |
|---|---|---|---|---|
| 1.5 ton | SEER2 14.3 | 1,259 | $0.23 | $172 |
| 2 ton | SEER2 14.3 | 1,678 | $0.31 | $229 |
| 2.5 ton | SEER2 14.3 | 2,098 | $0.38 | $286 |
| 3 ton | SEER2 14.3 | 2,517 | $0.46 | $343 |
| 3.5 ton | SEER2 14.3 | 2,937 | $0.53 | $401 |
| 4 ton | SEER2 14.3 | 3,357 | $0.61 | $458 |
| 5 ton | SEER2 14.3 | 4,196 | $0.76 | $572 |
24,000 BTU/h ÷ 14.3 = 1,678 W = 1.678 kW. × 18.19¢ = $0.31 per running hour. × 750 hours = $229 a year.
Prices are EIA's U.S. average residential price for Jan–Aug 2026. Efficiency figures are ENERGY STAR certified averages (window units) or the federal minimum shown.
The full method, material data and tips are on the main air conditioner cost calculator page.